Desalination and Water Treatment
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2024
·Vol. 57
·期 59
·28947-28956
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IF 1
Qiao Wang,Guang-shan Zhang,Han Chen,Peng Wang
A specially designed combined process of pre-oxidation and nanofiltration membrane was utilized to remove As(III) in the contaminated water without reagent addition and sediment creation in this work. Different parameters that affected the rejections of As(III) and As(V) were discussed, including the initial concentration, pH of the feed, and the cross-flow filtration pressure. The rejection of As(III) was over 70% which was restricted to the high initial feed concentration, while it was around 40% under the other conditions. Whereas, the rejection of As(V) maintained above 95% in all tests. As a result, As(III) was first pre-oxidized before membrane filtration. The ozone and aeration oxidation methods were used to oxidize As(III). The effects of aeration time and oxidation time were studied. The experimental results indicated that the rejection of As(III) was increased to over 90% after pre-oxidation, and the permeate could meet the drinking water standard for As in China. Particularly, the aeration took a much longer oxidation time than ozone, but it was still a more suitable method as the pre-oxidation process because of its safety and easy operability.
研究领域:
环境工程
·
水处理技术
·
膜分离
·
污染物控制
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xuebin Zhang,Yule Wang,Songhai Wu,Xingjian Dai,Yuxin Zhang,Li Feng,Xu Han
Schwertmannite (Sch) has been proved to be a promising and efficient adsorbent for the removal of various metal ions . However, how to further improve the adsorption capacity and stability of Sch to As(III), As(V) and P(V) is always a problem. In this study, we developed a method to synthesize various Schs with different initial ratios of SO 4 2- :Fe(III). Our results show that Schs can be used to remove As(III), As(V) and P(V) in a wide concentration range of pH 3.0–7.0, and negligible difference can be observed in the adsorption capacities of various Schs towards As(III), As(V) and P(V), indicating that increasing initial concentrations of SO 4 2- does not necessarily increase the adsorption capacity of Sch. In addition, the maximum adsorption capacities ( Q max ) of Sch-0.75 towards As(V) and P(V) increases with decreasing pHs, whereas increase with increasing pHs towards As(III). The Q max values of As(III), As(V) and P(V) are 80.5, 161.5 and 139.9 mg g −1 at pH 3.0, respectively, and are 214.5, 107.6 and 86.5 mg g −1 at pH 7.0, respectively, indicating that the strong dependence of Q max on pH values. Besides, we also successfully developed a method to synthesize the diatomite-modified Sch (DMS). The synthesized DMS with the ratio of Fe(III) salts and diatomite of 4:1 (DMS-4) shows the maximum adsorption capacities of As(III), As(V) and P(V) of 59.81, 151.52 and 236.97 mg g −1 at pH 3.0, respectively, and of 282.49, 126.58 and 165.02 mg g −1 at pH 7.0, respectively. DMS-4 also shows high stability during repeated experiments, and the removal efficiencies of DMS-4 to As(III), As(V) and P(V) maintain 97.42 %, 88.39 % and 94.72 % after five cycles, whereas the removal efficiencies of Sch-0.75 rapidly decrease to 63.61 %, 31.12 % and 50.71 % towards As(III), As(V) and P(V) after five cycles. This study provides a new method to synthesize stable DMS with high adsorption capacities towards As(III), As(V) and P(V).
研究领域:
环境科学
·
水处理技术
·
吸附材料
·
环境化学
·
污染控制
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）