作者机构：
[Wang, Aihe; Deng, Yumei; Zhang, Chun; Jiang, Haiyan] Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Zhang, Chun] H;Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Peoples R China.
摘要：
Antimony pollution resulting from industrial production is a great threat to the environment, ecology and the human body. Zero-valent iron powder is low-cost and easy to obtain. Nevertheless, the lower adsorption capacity limits its application when it is used as an adsorbent. In the present study, ball-milling and acid modification were developed to change its surface characteristics and gamma-Fe2O3, gamma-FeOOH and Fe3O4 were obtained after treatment, which promoted its adsorption capacity. Compared with the raw iron powder, the adsorption capacities for Sb(iii) and Sb(v) using the modified material were increased from 12.93 mg g(-1) and 5.47 mg g(-1) to 17.96 mg g(-1) and 10.58 mg g(-1), respectively. The study showed that the experimental data fitted the Langmuir model and the pseudo-first-order kinetic model better; the adsorption process was monolayer and chemically controlled at pH 5.0 +/- 0.2. XPS and FT-IR analysis showed that Fe-O-Sb bonds arose during the adsorption process. The effect of pH on the adsorption capacity was also studied and the pH affected the adsorption of Sb(v) more than the adsorption of Sb(iii). In addition, the modified iron powder presented better efficiency when applied to the removal of low levels of antimony in drinking water. Based on the increase of adsorption capacity and low cost, iron powder should be a promising adsorbent for aqueous antimony removal.
期刊：
Transactions of the Indian Institute of Metals,2019年72(10):2591-2597 ISSN：0972-2815
通讯作者：
Zhang, Chun
作者机构：
[Wang, Aihe; Deng, Yumei; Zhang, Chun; Jiang, Haiyan] Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Hunan, Peoples R China.
通讯机构：
[Zhang, Chun] H;Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
Iron recovery;Oxydrolysis;Goethite;Zinc neutral leaching residue;Magnetic seeds
摘要：
The recovery of iron is the key step for zinc recycling by electrolysis in zinc hydrometallurgy industry. Iron exists mainly as ferrites in the zinc neutral leaching residue and is difficult to decompose. In this paper, the reductive leaching process using sulfur dioxide was adopted to replace the traditional hot-acid leaching method, and the magnetic seed-assisted iron precipitation was developed. Under the optimum reductive leaching conditions, the initial concentration of sulfuric acid, the temperature and the partial pressure were determined as: 80 g/L H2SO4, 90 degrees C, 200 kPa at the fixed liquid/solid ratio of 10:1 and the stirring speed of 400 rpm. The most suitable iron precipitation reaction conditions were as follows: the pH: 3.0-3.5; the temperature: 95 degrees C. The recovery of iron mainly depended on the oxydrolysis of the ferrous. The ferrous precipitated as goethite and its crystallinity noticeably decreased with decreasing pH. The addition of the magnetic seeds shortened the reaction time from 4.5 to 3.0 h when the iron precipitation rate reached more than 99%. Simultaneously, the loss rates of zinc and cadmium in the iron process were also reduced from 10.96% and 9.27% to 4.23% and 3.73%, respectively. Besides, the sedimentation and filtration performance were greatly improved after the addition of magnetic seeds. The adsorption and inclusion were the main reasons for better sedimentation and filtration performance and higher metal loss rate.
期刊：
Korean Journal of Chemical Engineering,2018年35(8):1636-1641 ISSN：0256-1115
通讯作者：
Zhou, Kanggen
作者机构：
[Chen, Wei; Wang, Aihe; Liu, Xing; Chen, Quanzhou; Zhang, Chun; Liu, Fang; Zhou, Kanggen] Cent S Univ, Inst Environm Sci & Engn, Sch Met & Environm, Lushan South Rd 932, Changsha 410083, Peoples R China.;[Wang, Aihe] Hunan City Univ, Sch Municipal & Mapping Engn, Yingbin East Rd 518, Yiyang 413000, Hunan, Peoples R China.
通讯机构：
[Zhou, Kanggen] C;Cent S Univ, Inst Environm Sci & Engn, Sch Met & Environm, Lushan South Rd 932, Changsha 410083, Peoples R China.
关键词：
Metal Composite Oxides;Calcium Alginate;Fluoride;Adsorption Isotherm;Adsorption Kinetic;Regeneration
摘要：
Batch experiments were conducted to study the adsorption performance of fluorine removal by the calcium alginate (SA) embedded by the composite Mg-Al-Ce oxides (SA-CMAC). The physical and chemical properties of the SA-CMAC were characterized by XRD, SEM and XPS analysis. The optimum conditions for fluoride removal were determined and the maximum adsorption capacity was 26.12mg g−1. The co-existing PO
4
3−
and CO
3
2−
anions in solution had more effect than the SO
4
2−
and NO
3
-
on the fluoride removal efficiency. The adsorption process of fluorine by SA-CMAC was attributed to ion exchange on the surface of the SA-CMAC. The experimental data fitted both the isotherms and Freundlich well, and the Freundlich model had a little higher correlation coefficient. As the rate determining step, the adsorption process could be best described by the pseudo-second order kinetic model followed by the intra-particle diffusion. The thermodynamic examination demonstrated that the fluoride adsorption on the SA-CMAC beads was reasonably spontaneous and exothermic. The reclaimed adsorbents still could adsorb 65% of the total fluoride in the solution after three cyclic processes using 0.01mol/L NaOH.
作者：
Wang Aihe;Zhou Kanggen*;Liu Xing;Liu Fang;Zhang Chun;...
期刊：
Journal of Colloid and Interface Science,2017年505:947-955 ISSN：0021-9797
通讯作者：
Zhou Kanggen
作者机构：
[Wang Aihe; Chen Quanzhou; Liu Xing; Zhou Kanggen; Liu Fang] Cent S Univ, Sch Met & Environm, Lushan South Rd 932, Changsha 410083, Hunan, Peoples R China.;[Wang Aihe; Zhang Chun] Hunan City Univ, Sch Municipal & Mapping Engn, Yingbin East Rd 518, Yiyang 413000, Hunan, Peoples R China.
通讯机构：
[Zhou Kanggen] C;Cent S Univ, Sch Met & Environm, Lushan South Rd 932, Changsha 410083, Hunan, Peoples R China.
作者机构：
[王密; 张建强; 闵小波; 张纯; 李辕成] School of Metallurgy and Environment, Central South University, Changsha, China;[闵小波] Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South University, Changsha, China;[张纯] School of Municipal and Mapping Engineering, Hunan City University, Yiyang, China
通讯机构：
School of Metallurgy and Environment, Central South University, Changsha, China
作者机构：
[李辕成; 闵小波; 张建强; 王密] School of Metallurgical and Environment, Central South University, Changsha, Hunan 410083, China;School of Municipal and Mapping Engineering, Hunan City University, Yiyang, Hunan 413000, China;[张纯] School of Metallurgical and Environment, Central South University, Changsha, Hunan 410083, China, School of Municipal and Mapping Engineering, Hunan City University, Yiyang, Hunan 413000, China
通讯机构：
[Min, X.-B.] S;School of Metallurgical and Environment, Central South University, Changsha, Hunan, China
摘要：
The reductive acid leaching kinetics of synthetic cadmium-bearing zinc ferrite was investigated, and the influence of reaction temperature, sulfuric acid and hydrazine sulfate were studied. The results illustrated that an increase in the reaction temperature, initial sulfuric acid and hydrazine sulfate significantly enhanced the extraction efficiencies of cadmium, zinc and iron. The leaching kinetics were controlled by a surface chemical reaction based on a shrinking core model. The empirical equation
$$ 1 - (1 - X)^{{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 3}}\right.\kern-0pt} \!\lower0.7ex\hbox{$3$}}}} = k_{\text{r}} t $$
applied was found to fit well with the kinetics analysis; the leaching processes of cadmium, zinc and iron were similar and the activation energies were 79.9 kJ/mol, 77.9 kJ/mol and 79.7 kJ/mol, respectively. The apparent orders of cadmium-bearing zinc ferrite dissolution with respect to sulfuric acid concentration were 0.83, 0.83 and 0.84 for Cd, Zn and Fe, respectively.
摘要：
Zinc neutral leaching residue (ZNLR) from hydrometallurgical zinc smelting processing can be determined as hazardous intermediate containing considerable amounts of Cd and Zn which have great threats to the environment. The ZNLR contained approximately 35.99% Zn, 15.93% Fe and 0.26% Cd, and Cd mainly existed as ferrites in the ZNLR in this research. Reductive acid leaching of ZNLR was investigated. The effects of hydrazine sulfate concentration, initial sulfuric acid concentration, temperature, duration and liquid-to-solid ratio on the extraction of Cd, Zn and Fe were examined. The extraction efficiencies of Cd, Zn and Fe reached 90.81%, 95.83% and 94.19%, respectively when the leaching parameters were fixed as follows:hydrazine sulfate concentration, 33.3 g/L; sulfuric acid concentration, 80 g/L; temperature, 95 ℃; duration of leaching, 120 min; liquid-to-solid ratio, 10 mL/g and agitation, 400 r/min. XRD and SEM-EDS analyses of the leaching residue confirmed that lead sulfate (PbSO_4) and hydrazinium zinc sulfate((N_2H_5)_2Zn(SO_4)_2) were the main phases remaining in the reductive leaching residue.
摘要：
In this work, zinc neutral leaching residue was mechanically activated by ball-milling. The subsequent leaching behavior and kinetics of cadmium extraction in a mixed SO2-H2SO4 system were studied. Changes in the crystalline phase, lattice distortion, particle size and morphology, which were induced by mechanical activation, were also investigated. The activated samples showed different physicochemical characteristics, and cadmium extraction was found to be easier than for the un-activated samples. Under the same conditions, mechanical activation contributed to higher cadmium leaching. The cadmium extraction kinetics at 75–95°C was found to fit the shrinking core model. The raw neutral leaching residue, and the samples activated for 60 min and 120 min had a calculated activation energy of 65.02 kJ/mol, 59.45 kJ/mol and 53.46 kJ/mol, respectively. The leaching residue was characterized by ICP, XRD and SEM analysis. According to XRD analysis, the main phases in the residue were lead sulfate (PbSO4), zinc sulfide (ZnS) and cadmium sulfide (CdS).
