摘要：
Pb contamination is a serious environmental concern, posing significant threats to ecosystems and human health. Biochar-based functional materials have attracted considerable attention owing to their great potential for practical application. In this study, a novel N-functionalized tourmaline-biochar composite (TNBC) from pomelo peels with co-modifications using urea and tourmaline was developed. The immobilization of Pb in solution and soil by TNBC was investigated, and influencing factors and mechanisms were also analyzed. The experimental maximum adsorption capacity of Pb 2+ on TNBC was 600.60 mg/g. Analysis of morphologies and surface functional groups revealed that precipitation regulated Pb 2+ adsorption on TNBC, followed by cation exchange, complexation, and metal-π interaction. The effect of co-existing cations in the solution on adsorption was marginal. Correlation analysis disclosed that enriched plenty of minerals and N-functional groups on TNBC surface were the main reasons for improving Pb 2+ adsorption on TNBC compared with pristine biochar. Moreover, TNBC exhibited potential for soil remediation and could be an alternative amendment for Pb contamination. The TNBC increased the pH, electroconductivity, and residual Pb content of the polluted soil; therefore, it can ameliorate the effects of Pb contamination in the soil. This study provides an alternative viewpoint on developing functionalized biochar composites for soil remediation.
Pb contamination is a serious environmental concern, posing significant threats to ecosystems and human health. Biochar-based functional materials have attracted considerable attention owing to their great potential for practical application. In this study, a novel N-functionalized tourmaline-biochar composite (TNBC) from pomelo peels with co-modifications using urea and tourmaline was developed. The immobilization of Pb in solution and soil by TNBC was investigated, and influencing factors and mechanisms were also analyzed. The experimental maximum adsorption capacity of Pb 2+ on TNBC was 600.60 mg/g. Analysis of morphologies and surface functional groups revealed that precipitation regulated Pb 2+ adsorption on TNBC, followed by cation exchange, complexation, and metal-π interaction. The effect of co-existing cations in the solution on adsorption was marginal. Correlation analysis disclosed that enriched plenty of minerals and N-functional groups on TNBC surface were the main reasons for improving Pb 2+ adsorption on TNBC compared with pristine biochar. Moreover, TNBC exhibited potential for soil remediation and could be an alternative amendment for Pb contamination. The TNBC increased the pH, electroconductivity, and residual Pb content of the polluted soil; therefore, it can ameliorate the effects of Pb contamination in the soil. This study provides an alternative viewpoint on developing functionalized biochar composites for soil remediation.
摘要：
Sepiolite (SEP), a naturally abundant and environmentally friendly clay mineral, possesses various active sites and a large specific surface area. In this work, peroxymonosulfate (PMS) was activated to remove tetracycline (TC) using modified Sepiolite (MSEP), which was synthesized by ball milling and calcination techniques. According to the findings, MSEP efficiently stimulated PMS to produce 1 O 2 and ·OH radicals for the degradation of TC, with 1 O 2 being a key component of this process. The findings demonstrated that the carbonate on the MSEP surface encouraged the production of singlet oxygen. ( 1 O 2 ). Under the conditions of pH 6.5, 0.2 g/L MSEP, 2 mmol/L PMS and 25 °C, a 10 mg/L TC concentration was reduced by 93.3 % after 30 min. The presence of Cl − and NO 3 − did not inhibit TC degradation, while HCO 3 − promoted it, and H 2 PO 4 − exhibited an inhibitory effect. This work offers a novel method for using clay minerals to activate PMS and degrade organic contaminant without secondary pollution.
Sepiolite (SEP), a naturally abundant and environmentally friendly clay mineral, possesses various active sites and a large specific surface area. In this work, peroxymonosulfate (PMS) was activated to remove tetracycline (TC) using modified Sepiolite (MSEP), which was synthesized by ball milling and calcination techniques. According to the findings, MSEP efficiently stimulated PMS to produce 1 O 2 and ·OH radicals for the degradation of TC, with 1 O 2 being a key component of this process. The findings demonstrated that the carbonate on the MSEP surface encouraged the production of singlet oxygen. ( 1 O 2 ). Under the conditions of pH 6.5, 0.2 g/L MSEP, 2 mmol/L PMS and 25 °C, a 10 mg/L TC concentration was reduced by 93.3 % after 30 min. The presence of Cl − and NO 3 − did not inhibit TC degradation, while HCO 3 − promoted it, and H 2 PO 4 − exhibited an inhibitory effect. This work offers a novel method for using clay minerals to activate PMS and degrade organic contaminant without secondary pollution.
关键词：
Peroxydisulfate;Non-radical pathway;Electron transfer pathway;High stability
摘要：
The non-radical pathway has attracted extensive interest due to its unique advantages in persulfate activation. However, the conversion between non-radical pathways remains elusive. In this study, the nitrogen and boron co-doped carbon (NB-C) was synthesized from agroforestry waste by a simple co-pyrolysis method for activating peroxydisulfate (PDS) to degrade sulfamethoxazole (SMX). The results showed that nearly 100 % removal of SMX (20 mg/L) was achieved at a low catalyst dose (0.15 g L −1 ). Combining the results of quenching experiments, electron paramagnetic resonance, in situ Raman spectroscopy, premixing experiments, and electrochemical analyses, a non-radical activation mechanism dominated by the electron transfer pathway (ETP) was identified. More importantly, we have quantified the oxidation contribution of various reactive oxygen species (ROS) to SMX degradation by steady-state concentration calculations. The experimental and characterization data indicated that the carbon structure of nitrogen-doped carbon (N-C) was altered with the introduction of boron (B), and the main active sites were replaced by pyrrolic N, sp 2 -C, and the new BC 3 site, thereby transforming the reaction pathway from 1 O 2 oxidation (44.43 %) into an almost complete ETP (92.34 %). Benefitting from the advantages of the ETP, the NB-C/PDS system maintains excellent adaptability in complex background water matrices and over a wide pH range (3−11). Moreover, unlike the N-C/PDS system based on 1 O 2 oxidation, the reusability of the NB-C/PDS system was significantly improved, which further emphasizes its practical application potential. Finally, three possible degradation pathways of SMX were proposed by liquid chromatography-mass spectrometry and the toxicity of the intermediates was evaluated.
The non-radical pathway has attracted extensive interest due to its unique advantages in persulfate activation. However, the conversion between non-radical pathways remains elusive. In this study, the nitrogen and boron co-doped carbon (NB-C) was synthesized from agroforestry waste by a simple co-pyrolysis method for activating peroxydisulfate (PDS) to degrade sulfamethoxazole (SMX). The results showed that nearly 100 % removal of SMX (20 mg/L) was achieved at a low catalyst dose (0.15 g L −1 ). Combining the results of quenching experiments, electron paramagnetic resonance, in situ Raman spectroscopy, premixing experiments, and electrochemical analyses, a non-radical activation mechanism dominated by the electron transfer pathway (ETP) was identified. More importantly, we have quantified the oxidation contribution of various reactive oxygen species (ROS) to SMX degradation by steady-state concentration calculations. The experimental and characterization data indicated that the carbon structure of nitrogen-doped carbon (N-C) was altered with the introduction of boron (B), and the main active sites were replaced by pyrrolic N, sp 2 -C, and the new BC 3 site, thereby transforming the reaction pathway from 1 O 2 oxidation (44.43 %) into an almost complete ETP (92.34 %). Benefitting from the advantages of the ETP, the NB-C/PDS system maintains excellent adaptability in complex background water matrices and over a wide pH range (3−11). Moreover, unlike the N-C/PDS system based on 1 O 2 oxidation, the reusability of the NB-C/PDS system was significantly improved, which further emphasizes its practical application potential. Finally, three possible degradation pathways of SMX were proposed by liquid chromatography-mass spectrometry and the toxicity of the intermediates was evaluated.
通讯机构：
[Xiang, XA ] H;Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
Energy Efficiency;Exergy Efficiency;Dual Fluidized Bed;Gasification
摘要：
In the evaluation of energy conversion processes, EnE (Energy Efficiency) and ExE (exergy efficiency) are currently used as the main indicators. However, this paper contends that such evaluations are incomplete and proposes incorporating DEnEx (Difference Between Energy Efficiency and Exergy Efficiency). The DEnEx reflects the energy losses caused by irreversible processes within the system, revealing the extent to which the system deviates from its ideal state during operation. This paper provides a detailed analysis of EnE, ExE, and DEnEx using the dual fluidized bed as an example, leading to the following conclusions: (1) An increase in gasification temperature and the FC (Fixed Carbon) content of raw materials raises both EnE and ExE, while increases in S/C (steam to carbon ratio) and auxiliary fuel initially raise both EnE and ExE but eventually lead to a decline. (2) Altering gasification conditions and auxiliary fuel can improve both EnE and ExE, but may also increase DEnEx. If equipment optimization is guided by DEnEx, it could produce results that contradict EnE and ExE analysis. This discrepancy arises mainly because changes in conditions aimed at enhancing system efficiency do not account for variations in internal exergy losses. (3) The catalytic gasification method can simultaneously increase EnE and ExE while reducing DEnEx, demonstrating a more comprehensive optimization approach. Therefore, in optimizing the dual fluidized bed gasification process, the methods of altering operational conditions (gasification temperature, S/C, auxiliary fuel) are found to be imperfect and struggle to balance enhancing system efficiency with reducing irreversible losses. It is essential to change external conditions, such as utilizing raw materials with high FC content or adopting catalytic gasification, to achieve comprehensive optimization. Furthermore, in evaluating energy conversion processes, solely considering EnE and ExE is insufficient; incorporating DEnEx is necessary. Only by achieving simultaneous optimization of all three metrics can the best optimization solution be realized.
In the evaluation of energy conversion processes, EnE (Energy Efficiency) and ExE (exergy efficiency) are currently used as the main indicators. However, this paper contends that such evaluations are incomplete and proposes incorporating DEnEx (Difference Between Energy Efficiency and Exergy Efficiency). The DEnEx reflects the energy losses caused by irreversible processes within the system, revealing the extent to which the system deviates from its ideal state during operation. This paper provides a detailed analysis of EnE, ExE, and DEnEx using the dual fluidized bed as an example, leading to the following conclusions: (1) An increase in gasification temperature and the FC (Fixed Carbon) content of raw materials raises both EnE and ExE, while increases in S/C (steam to carbon ratio) and auxiliary fuel initially raise both EnE and ExE but eventually lead to a decline. (2) Altering gasification conditions and auxiliary fuel can improve both EnE and ExE, but may also increase DEnEx. If equipment optimization is guided by DEnEx, it could produce results that contradict EnE and ExE analysis. This discrepancy arises mainly because changes in conditions aimed at enhancing system efficiency do not account for variations in internal exergy losses. (3) The catalytic gasification method can simultaneously increase EnE and ExE while reducing DEnEx, demonstrating a more comprehensive optimization approach. Therefore, in optimizing the dual fluidized bed gasification process, the methods of altering operational conditions (gasification temperature, S/C, auxiliary fuel) are found to be imperfect and struggle to balance enhancing system efficiency with reducing irreversible losses. It is essential to change external conditions, such as utilizing raw materials with high FC content or adopting catalytic gasification, to achieve comprehensive optimization. Furthermore, in evaluating energy conversion processes, solely considering EnE and ExE is insufficient; incorporating DEnEx is necessary. Only by achieving simultaneous optimization of all three metrics can the best optimization solution be realized.
摘要：
Spinel oxide has attracted interest in wastewater treatment, owing to its visible light (VIS) adsorption properties and bimetallic synergism. However, owing to the inefficient separation of photogenerated carriers and poor redox property, there is an urgent need to develop appropriate modification strategies to address these bottlenecks. This study aimed to develop CuFe 2 O 4 /CuFeSx (CFO/CFSx) heterojunction with oxygen vacancies (OVs) via an in-situ structural modification to trigger the generation of more radicals with low oxidant consumption for the efficient degradation of refractory organics. This customized heterojunction improved the light-trapping ability and photoelectrons utilisation, promoting the reduction of metal valence by photoelectrons to enhance the activation of peroxymonosulfate (PMS). Meanwhile, OVs also provided more active sites to activate PMS to generate superoxide radicals (O 2 − ), which were further converted to hydroxyl radicals ( OH) to ensure considerable oxidation capability. Notably, Sulfur-mediated metal valence reduction boosted the cycle of Cu(I)/Cu(II) and Fe(II)/Fe(III), guaranteeing the regeneration of the active sites. Triple optimisation of the modified spinel oxide presented a striking oxidant utilisation efficiency with a substantial increase in the concentration of radicals. This study provides a simple and reliable reference for designing high-performance CuFe 2 O 4 (CFO) photocatalysts for environmental remediation.
Spinel oxide has attracted interest in wastewater treatment, owing to its visible light (VIS) adsorption properties and bimetallic synergism. However, owing to the inefficient separation of photogenerated carriers and poor redox property, there is an urgent need to develop appropriate modification strategies to address these bottlenecks. This study aimed to develop CuFe 2 O 4 /CuFeSx (CFO/CFSx) heterojunction with oxygen vacancies (OVs) via an in-situ structural modification to trigger the generation of more radicals with low oxidant consumption for the efficient degradation of refractory organics. This customized heterojunction improved the light-trapping ability and photoelectrons utilisation, promoting the reduction of metal valence by photoelectrons to enhance the activation of peroxymonosulfate (PMS). Meanwhile, OVs also provided more active sites to activate PMS to generate superoxide radicals (O 2 − ), which were further converted to hydroxyl radicals ( OH) to ensure considerable oxidation capability. Notably, Sulfur-mediated metal valence reduction boosted the cycle of Cu(I)/Cu(II) and Fe(II)/Fe(III), guaranteeing the regeneration of the active sites. Triple optimisation of the modified spinel oxide presented a striking oxidant utilisation efficiency with a substantial increase in the concentration of radicals. This study provides a simple and reliable reference for designing high-performance CuFe 2 O 4 (CFO) photocatalysts for environmental remediation.
期刊：
Chemical Engineering Journal,2025年:163595 ISSN：1385-8947
通讯作者：
Yaoning Chen<&wdkj&>Yuanping Li
作者机构：
[Hongjuan Jiang; Zhigang Yi; Yaoning Chen; Jun Wang; Li Chen; Yihang He; Nan Wang; Qianruyu Wang] College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China;[Yuanping Li; Wei Zhang] School of Municipal and Geomatics Engineering, Hunan City University, Yiyang, Hunan 413000, China;[Yanrong Chen] School of Resource & Environment, Hunan University of Technology and Business, Changsha 410205, China
通讯机构：
[Yaoning Chen] C;[Yuanping Li] S;College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China<&wdkj&>School of Municipal and Geomatics Engineering, Hunan City University, Yiyang, Hunan 413000, China
摘要：
Agricultural waste composting could be useful for remediating soils contaminated by heavy metals (HMs). However, the mechanism of how straw degradation during composting affects HMs immobilization has not been deeply explored. This study intends to decipher the mechanisms underlying the effect of straw degradation and microbial activity on HMs immobilization with the help of the exogenous addition of laccase during composting. The results demonstrated that the exogenous laccase increased straw degradation and humic acid by 6.37 and 1.07 times, respectively, and reduced the bioavailable states of Pb and Cu by 7.18% and 20.57% respectively. Functional groups (alcohols, ethers, quinone, conjugated ketones, aromatic carbon skeleton, phenol in cellulose, hemicellulose, and lignin) dominated the binding of HMs during straw degradation. The exogenous laccase promoted bacteria ( Bacillus , Lactobacillus , and Bifidobacterium ) adsorbing and binding HMs, while facilitating straw degradation and humus synthesis via enhancing amino acid and carbohydrate metabolism, contributing to the HMs immobilization by increasing functional groups. This study offers comprehensive information into the mechanisms of HM immobilization by straw biodegradation during agricultural waste composting, contributing to the application of composting for remediating HM-contaminated soils.
Agricultural waste composting could be useful for remediating soils contaminated by heavy metals (HMs). However, the mechanism of how straw degradation during composting affects HMs immobilization has not been deeply explored. This study intends to decipher the mechanisms underlying the effect of straw degradation and microbial activity on HMs immobilization with the help of the exogenous addition of laccase during composting. The results demonstrated that the exogenous laccase increased straw degradation and humic acid by 6.37 and 1.07 times, respectively, and reduced the bioavailable states of Pb and Cu by 7.18% and 20.57% respectively. Functional groups (alcohols, ethers, quinone, conjugated ketones, aromatic carbon skeleton, phenol in cellulose, hemicellulose, and lignin) dominated the binding of HMs during straw degradation. The exogenous laccase promoted bacteria ( Bacillus , Lactobacillus , and Bifidobacterium ) adsorbing and binding HMs, while facilitating straw degradation and humus synthesis via enhancing amino acid and carbohydrate metabolism, contributing to the HMs immobilization by increasing functional groups. This study offers comprehensive information into the mechanisms of HM immobilization by straw biodegradation during agricultural waste composting, contributing to the application of composting for remediating HM-contaminated soils.
摘要：
In this study, tin sulphide (SnS2) and nickel-chromium hydrotalcite (NiCr-LDH) complexes (SnS2/NiCr-LDH) were used for the simultaneous removal of U(VI) and humic acid (HA) from U(VI)-containing wastewater. The results showed that the adsorption of HA by the SnS2/NiCr-LDH was greatly enhanced, which was 4.07 and 2.94 times higher than that of pure SnS2 and NiCr-LDH, respectively, and the highest U(VI) adsorption quantity over SnS2/NiCr-LDH increased from 127.81 to 446.68 mg g(-1) when HA was present. Density functional theory (DFT) calculations revealed that the enhanced U(VI) adsorption on SnS2/NiCr-LDH was facilitated by the formation of a robust inner-sphere surface complex between U(VI) and HA.
摘要：
Tunning facet strategy has been a fundamental method for enhancing photocatalytic activity by manipulating electrons and hole separation. Herein, three morphological-dependent CdS catalysts are employed for uranium(VI)-containing wastewater photoreduction. The apparent rates of U(VI) photocatalytic reduction ( k obs , U(VI) ) follow the order of CdS nanorod (CdS-Rod, 0.3710 min −1 ) > leaf-like CdS (CdS-Leaf, 0.0394 min −1 ) > sphere-like CdS (CdS-Sphere, 0.0273 min −1 ). Among them, CdS nanorods (CdS-Rod) achieved over 99 % uranium(VI) removal within 15 min at an initial U(VI) concentration of 30 mg L −1 . As explored by band structure analysis and EPR combine with quenching experiments, the more negative conduction positions of CdS-Rod led to more formation of O 2 – due to stronger reducibility of electron than CdS-Leaf and CdS-Sphere. Improved separation efficiency of photogenerated carriers further led to increased electron and O 2 – generation, which are decisive species for photocatalytic reduction of uranium(VI). Besides, variations in intrinsic photoactivity were analyzed taking into consideration the changes in the specific surface area, crystallinity, exposed facet ratio, and light absorption ability of CdS catalysts. Benefiting from the higher exposure content of the {1 0 0} facet and the facet ratio of {1 0 0}/{0 0 1}, the CdS-Leaf catalysts exhibits a highest surface area normalized rate. Density functional theory (DFT) calculations subsequently confirmed that the {1 0 0} crystal facet of CdS is more conducive to uranyl ions adsorption than {0 0 1} facet due to more unsaturated three-coordinate S atoms in CdS {1 0 0} model. This work unveils the role of morphology in affecting photoexcited carrier dynamic, highlighting opportunities for remediating U(VI)-containing radioactive wastewater.
Tunning facet strategy has been a fundamental method for enhancing photocatalytic activity by manipulating electrons and hole separation. Herein, three morphological-dependent CdS catalysts are employed for uranium(VI)-containing wastewater photoreduction. The apparent rates of U(VI) photocatalytic reduction ( k obs , U(VI) ) follow the order of CdS nanorod (CdS-Rod, 0.3710 min −1 ) > leaf-like CdS (CdS-Leaf, 0.0394 min −1 ) > sphere-like CdS (CdS-Sphere, 0.0273 min −1 ). Among them, CdS nanorods (CdS-Rod) achieved over 99 % uranium(VI) removal within 15 min at an initial U(VI) concentration of 30 mg L −1 . As explored by band structure analysis and EPR combine with quenching experiments, the more negative conduction positions of CdS-Rod led to more formation of O 2 – due to stronger reducibility of electron than CdS-Leaf and CdS-Sphere. Improved separation efficiency of photogenerated carriers further led to increased electron and O 2 – generation, which are decisive species for photocatalytic reduction of uranium(VI). Besides, variations in intrinsic photoactivity were analyzed taking into consideration the changes in the specific surface area, crystallinity, exposed facet ratio, and light absorption ability of CdS catalysts. Benefiting from the higher exposure content of the {1 0 0} facet and the facet ratio of {1 0 0}/{0 0 1}, the CdS-Leaf catalysts exhibits a highest surface area normalized rate. Density functional theory (DFT) calculations subsequently confirmed that the {1 0 0} crystal facet of CdS is more conducive to uranyl ions adsorption than {0 0 1} facet due to more unsaturated three-coordinate S atoms in CdS {1 0 0} model. This work unveils the role of morphology in affecting photoexcited carrier dynamic, highlighting opportunities for remediating U(VI)-containing radioactive wastewater.
摘要：
The Fenton-like system and electric field assistance are two novel and efficient strategies to improve traditional composting. However, the coupling impacts of the Fenton-like system and electric field assistance on humification and greenhouse gas emissions in composting are rarely studied. Therefore, this study used an iron plate as the electrode material to construct a new electro-Fenton system by adding CaO 2 particles and evaluated the effects and potential mechanisms of this system on humification and greenhouse gas emissions in composting. The results showed that the electro-Fenton system not only effectively promoted more precursor substances to form humic substances by participating in the Maillard reaction, but also effectively enriched electroactive bacteria such as Bacillus , Geobacillus , and Klebsiella , which facilitated the humification by accelerating electron transfer. In addition, the electro-Fenton system effectively reduced greenhouse gas emissions. In summary, electro-Fenton is an effective strategy to improve humification and reduce greenhouse gas emissions during composting.
The Fenton-like system and electric field assistance are two novel and efficient strategies to improve traditional composting. However, the coupling impacts of the Fenton-like system and electric field assistance on humification and greenhouse gas emissions in composting are rarely studied. Therefore, this study used an iron plate as the electrode material to construct a new electro-Fenton system by adding CaO 2 particles and evaluated the effects and potential mechanisms of this system on humification and greenhouse gas emissions in composting. The results showed that the electro-Fenton system not only effectively promoted more precursor substances to form humic substances by participating in the Maillard reaction, but also effectively enriched electroactive bacteria such as Bacillus , Geobacillus , and Klebsiella , which facilitated the humification by accelerating electron transfer. In addition, the electro-Fenton system effectively reduced greenhouse gas emissions. In summary, electro-Fenton is an effective strategy to improve humification and reduce greenhouse gas emissions during composting.
摘要：
The variation in pollutant concentrations among different water bodies poses a significant challenge for environmental surveillance. Traditional UV-Vis spectrometers, with fixed optical paths, face limitations in accurately determining Chemical Oxygen Demand (COD) and other water quality parameters. High concentrations surpass the detection limit, while low concentrations yield weak response signals, thereby compromising measurement accuracy. This study tackles these challenges by enhancing a UV-Vis spectrometer with a variable optical path. By utilizing a right-angle reflector for reflection and a stepping motor for control, measurements are conducted within the wavelength range of 190–700 nm. The instrument incorporates a spectral fusion algorithm to optimize spectral measurements within its operational range. Furthermore, a Partial Least Squares (PLS) model has been established for COD inversion by using laboratory standard solutions and field samples. The spectrometer has been tested in the nearshore waters of Shenzhen Bay, China, validating its applicability and the model’s accuracy. The utilization of a variable optical path UV-Vis spectrometer facilitates the acquisition of precise monitoring data with wide measuring range, thereby enabling the prompt detection of anomalies and subsequent reduction in reaction time.
期刊：
Science of The Total Environment,2025年959:178236 ISSN：0048-9697
通讯作者：
Yaoning Chen<&wdkj&>Guangming Zeng
作者机构：
[Yi, Zhigang; Wang, Qianruyu; Luo, Mengwei; Wang, Jun; Jiang, Hongjuan; Chen, Li; Nie, Yaoqin] College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China;[Chen, Yaoning] College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China. Electronic address: cyn@hnu.edu.cn;[Li, Yuanping] School of Municipal and Geomatics Engineering, Hunan City University, Yiyang, Hunan 413000, China. Electronic address: yuanpingli@hncu.edu.cn;[Wu, Yanting; Zhang, Wei] School of Municipal and Geomatics Engineering, Hunan City University, Yiyang, Hunan 413000, China;[Zeng, Guangming] College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China. Electronic address: zgming@hnu.edu.cn
通讯机构：
[Yaoning Chen; Guangming Zeng] C;College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
摘要：
This study aimed to enhance humification and cadmium (Cd) remediation in compost by investigating the effects of three post-treatments: ultrapure water, citric acid, and ethylenediaminetetraacetic acid disodium (EDTA). The results revealed that the EDTA post-treatment significantly enhanced humification by facilitating an EDTA-Fenton-like system within compost comprising rice straw and river sediment to remediate Cd-contaminated sediment. EDTA post-treatment not only promoted humic substances and humic acid concentrations of up to 66.30 g/kg and 30.40 g/kg, respectively, but also led to a reduction in the Cd content and bioavailability factor by 75.02 % and 9.76 %, respectively. In addition, parallel factor analysis revealed two distinct components, while two-dimensional correlation spectroscopy showed that the polysaccharides and carboxyl groups in humic acid were preferentially bound to Cd. Overall, this study proposes a promising approach for enhancing humification and Cd remediation in compost by the EDTA post-treatment.
This study aimed to enhance humification and cadmium (Cd) remediation in compost by investigating the effects of three post-treatments: ultrapure water, citric acid, and ethylenediaminetetraacetic acid disodium (EDTA). The results revealed that the EDTA post-treatment significantly enhanced humification by facilitating an EDTA-Fenton-like system within compost comprising rice straw and river sediment to remediate Cd-contaminated sediment. EDTA post-treatment not only promoted humic substances and humic acid concentrations of up to 66.30 g/kg and 30.40 g/kg, respectively, but also led to a reduction in the Cd content and bioavailability factor by 75.02 % and 9.76 %, respectively. In addition, parallel factor analysis revealed two distinct components, while two-dimensional correlation spectroscopy showed that the polysaccharides and carboxyl groups in humic acid were preferentially bound to Cd. Overall, this study proposes a promising approach for enhancing humification and Cd remediation in compost by the EDTA post-treatment.
摘要：
This study prepared pomelo peel biochar (PBC) under different pyrolysis temperatures (T) (300-800 degrees C) and investigated the removal efficiency of tetracycline (TC) under the oxidative systems established by PBC and oxidants (hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and peroxydisulfate (PDS)). The correlation between the properties of PBC and the removal efficiencies of TC was studied by Pearson analysis to clarify the critical properties of biochar in catalytic processes. The inorganic carbon (IC), ash, pH, basic functional groups (BFG), specific surface area (SSA), microporous surface area (S-micro), pore volume (PV), and graphitization degree (I-D/I-G) of PBC were positively correlated with the increase of T (p < 0.05). Notably, the SSA and PV of PBC increased from 4.294 m(2)/g and 0.002 cm(3)/g to 496.864 m(2)/g and 0.261 cm(3)/g as the pyrolysis temperature increased from 300 to 800 degrees C. In contrast, the yield, organic carbon (OC), and acidic functional groups (AFG) of PBC displayed negatively correlated with the increase of T (p < 0.05). R-ad, R-PBC/H2O2, R-PBC/PMS, and R-PBC/PDS represented the removal efficiencies of TC by PBC adsorption, PBC/H2O2, PBC/PMS, and PBC/PDS system. R-PBC/H2O2, R-PBC/PMS, and R-PBC/PDS showed a highly positive correlation to the R-ad (r = 0.965, 0.952, 0.946, p < 0.01). R-ad, R-PBC/H2O2, R-PBC/PMS, and R-PBC/PDS were positively correlated with K, Mg, ash, pH, BFG, and I-D/I-G (p < 0.01). There was no statistically significant correlation between persistent free radicals (PFRs) and the removal efficiencies of TC. Furthermore, SSA and PV showed positive relationships with the removal efficiencies of TC in the PBC/PMS and PBC/PDS systems, but no significant correlation with the removal efficiencies of TC in the PBC/H2O2 systems. Moreover, the catalytic behaviors and mechanisms were studied in the PBC-800 based oxidative systems. The quenching experiments and EPR spectra indicated that singlet oxygen (O-1(2)) was the main active species. Except for O-1(2), superoxide radical (O-2(center dot-)) also contributed to TC removal in the oxidative systems. From the changes in used PBC-800, the disordered sp(2) hybrid carbon, sp(3) C-C, and pyridinic-N were the main active sites in activation.
摘要：
Satellite-based aerosol optical depth (AOD) products are commonly used in various aerosol-related studies, such as aerosol pollution mapping and aerosol-climate interactions. However, these satellite AOD products often suffer from significant missing gaps due to cloud cover and limitations in the retrieval algorithm. To address this issue, some studies take advantage of real-time seamless simulation of numerical models and successfully fill in these gaps by establishing a regression relationship between satellite AOD and numerical model AOD. However, these previous studies usually use satellite AOD retrievals as the regression target, which limits the accuracy of the imputation results by the original accuracy of satellite AOD retrievals and also consumes a considerable amount of time. To overcome these limitations, this study proposes a spatiotemporal imputation model called Bi-ConvRNN, which combines convolutional neural networks (CNN) and bidirectional recurrent neural networks (Bi-RNN). The model takes both satellite AOD retrievals and numerical model AOD data as input and utilizes the weighted mean squared error (MSE) loss function of multiple AOD datasets, e.g., ground-based data, satellite retrievals, and numerical simulation, as the optimization target to improve the imputation accuracy. The proposed model is evaluated using hourly COMS GOCI AOD products. In the independent test set, the AOD results generated by the Bi-ConvRNN model in the region containing GOCI AOD retrievals can break the accuracy of original GOCI AOD products with the accuracy improved from R2 = 0.70 [RMSE = 0.15] to R2 = 0.84 [RMSE = 0.11], and the filling accuracy, e.g. R2 = 0.79, [RMSE = 0.14], in the region without GOCI AOD retrievals are still better than those of the original GOCI AOD retrievals. Additionally, the Bi-ConvRNN model demonstrates satisfactory filling efficiency, requiring only 0.12 s to fill in the missing gaps of hourly GOCI AOD products per day. These results highlight the efficiency and reliability of the proposed model in filling the gaps in satellite AOD products, and the filled AOD results have great potential for further aerosol-related research.
关键词：
Rosgen stream classification;Fluvial Processes;Geometric Channel Parameters;The Shiyang River
摘要：
The Shiyang River is an important ecological pillar in northwest China, sustaining Minqin oasis and its surrounding society. However, the basin has long been plagued by water scarcity and ecological fragility. Although the river classification is critical for understanding the complexity, diversity, and ecological functions of rivers, and the foundation of river management and watershed ecological restoration, it has not received adequate attention in this region. To obtain a deeper and comprehensive understanding of the Shiyang River, this study utilizes the Rosgen stream classification system to assess the river morphology, geomorphic features, and hydrologic processes. The results showed that seven first-level and fourteen second-level river types can be identified along 53 river sections of the Shiyang River. Further comparison analysis on the hydrologic parameters for each river type demonstrated a strong positive correlation between discharge and all river parameters. As discharge increased, channels with moderate to high width/depth ratios experienced significant lateral adjustments. A consistent channel gradient, coupled with higher discharge, facilitated the transition from single to multiple channels. Braiding tendencies were more pronounced in rivers where riverbeds were wider and shallower with higher stream power. Additionally, water-flow shear stress decreased with the increase in the width/depth ratio. This study offered critical insights into the Shiyang River's forms and processes and for the river management and ecological restoration practices.
摘要：
The serial compound fluidized bed gasification process of HMSW (high moisture solid waste) is studied, and the semi-empirical kinetic model is established by combining hydrodynamics and reaction kinetics. The model include combustion sub-model and gasification sub-model, which are divided into dense phase and dilute phase for simulation. The dense phase is simulated by the three-phase bubble bed theory, and the dilute phase is simulated by Wen-Chen entrainment elutriation model combined with the ring-core model. The pyrolysis model is based on the empirical relationship. The effects of gasification temperature, S/HMSW (steam/high moisture solid waste) ratio, HMSW/C (high moisture solid waste/coal) ratio, and moisture on the gasification process are studied. The results show that the gasification temperature of 1000 degrees C, S/HMSW of 1.13, HMSW/C of 3, and moisture of 26% are the optimal gasification parameters. The study can guide the design, operation, and optimization of the serial compound gasification process.
摘要：
Novel tourmaline-biochar composites (TBs) were synthesized by introducing tourmaline (TM) into pomelo peel biochar (BC). The surface properties of TBs and BC were studied and the adsorption performances for Pb2+ were investigated. Compared to pristine BC, the adsorption ability for Pb2+ on TBs was enhanced with the increase of TM in TBs, and up to 514.62 mg/g on 5%TB. The enrichment of inorganic metals caused by TM in TBs made the precipitation and cation ion exchange become the main mechanisms in adsorbing Pb2+, and the amounts of adsorbing Pb2+ by those two mechanisms on TBs were 1.10–1.48 times and 1.20–1.30 times those of BC, respectively. Furthermore, applying TBs to practical contaminated soil increased the soil pH and electrical conductivity (EC) after 15 days of incubation. The increased content of residual-Pb and reduced exchangeable-Pb and DTPA-Pb indicated that TBs were favorable for the immobilization of Pb in soil. This study gives a new perspective on the synthesis of tourmaline-biochar composite and their application in Pb-polluted water and soil.
Novel tourmaline-biochar composites (TBs) were synthesized by introducing tourmaline (TM) into pomelo peel biochar (BC). The surface properties of TBs and BC were studied and the adsorption performances for Pb2+ were investigated. Compared to pristine BC, the adsorption ability for Pb2+ on TBs was enhanced with the increase of TM in TBs, and up to 514.62 mg/g on 5%TB. The enrichment of inorganic metals caused by TM in TBs made the precipitation and cation ion exchange become the main mechanisms in adsorbing Pb2+, and the amounts of adsorbing Pb2+ by those two mechanisms on TBs were 1.10–1.48 times and 1.20–1.30 times those of BC, respectively. Furthermore, applying TBs to practical contaminated soil increased the soil pH and electrical conductivity (EC) after 15 days of incubation. The increased content of residual-Pb and reduced exchangeable-Pb and DTPA-Pb indicated that TBs were favorable for the immobilization of Pb in soil. This study gives a new perspective on the synthesis of tourmaline-biochar composite and their application in Pb-polluted water and soil.
摘要：
The electric field-assisted composting system (EACS) is an emerging technology that can enhance composting efficiency, but little attention has been given to electrode materials. Herein, an EACS was established to investigate the effects of electrode materials on humic substance formation and heavy metal speciation. Excitation-emission matrix analysis showed that carbon-felt and stainless-steel electrodes increased humic acid (HA) by 48.57% and 47.53%, respectively. In the EACS with the carbon-felt electrode, the bioavailability factors (BF) of Cu and Cr decreased by 18.00% and 7.61%, respectively. Despite that the stainless-steel electrodes decreased the BF of As by 11.26%, the leaching of Cr, Ni, Cu, and Fe from the electrode itself is an inevitable concern. Microbial community analyses indicated that the electric field increased the abundance of Actinobacteria and stimulated the multiplication of heavy metal-tolerant bacteria. Redundancy analysis indicates that OM, pH, and current significantly affect the evolution of heavy metal speciation in the EACS. This study first evaluated the metal leaching risk of stainless-steel electrode, and confirmed that carbon-felt electrode is environment-friendly material with high performance and low risk in future research with EACS.
