Study On The Repair And Stability Of Mg???-Al???-CO₃ Hydrotalcite As Adsorbent For As???-ROX Polluted Wastewater

Inorganic arsenic in industrial wastewater or in solid waste landfill wastewater and organic arsenic in feed additives not only cause harm to the environment,but also directly harmed human health through the gradual flocculation of the food chain.In recent years,many researchers have focused on the mechanism of remediation of single polluted water or soil,ignoring the effects of the interaction of the natural water and soil on the remediation effect and the stability of adsorbed solids.In this paper,taking As?V?and ROX as the research objects,Mg?II?-Al?III?-CO₃ hydrotalcite?Mg/Al-HTLcs?with a wide range of sources and no secondary pollution was used to treat arsenic-contaminated wastewater.The concrete research results are as follows:?1?Optimal remediation conditions for As?V?/ROX contaminated wastewater were as follows:the ambient temperature was 25?,the rotational speed was 150 r/min,the dosage was 0.1500 g(the solid/liquid ratio was 3 mg·mL^-1)and the reaction time was 24 h,the initial pH was 3.0,the adsorption rate of As?V?/ROX single polluted wastewater reached the maximum.The adsorption rate were 99.40%and 99.70%.?2?Optimal remediation conditions for As?V?-ROX contaminated wastewater were as follows:the ambient temperature was 25?,the rotational speed was 150 r/min,the dosage was 0.2000 g(the solid/liquid ratio was 4 mg·mL^-1)and the reaction time was 24 h,the initial pH was 3.0,the adsorption rate of As?V?-ROX compound polluted wastewater reaches the maximum.The adsorption rate were 97.14%and 74.24%.The adsorption of As?V?by Mg/Al-HTLcs conforms to Langmuir isothermal model and second-order kinetic model,and the adsorption of ROX by Mg/Al-HTLcs conformed to freundlich isothermal model and first-order kinetic model.?3?The results of scanning electron microscopy?SEM??specific surface measurement?XRD and infrared spectroscopy showed that Mg/Al-HTLcs had good pore structure and large specific surface area(136 m²·g^-1),could be used as adsorbent to treat polluted wastewater.The crystal form of Mg/Al-HTLcs did not change significantly before and after adsorption,and the basic structure of Mg/Al-HTLcs remained unchanged.?4?The results of stability test showed that:The change of temperature,rotational speed and pH had a relatively low impact on the desorption rate and desorption rate.But H₂PO₄^-could accelerate the desorption of As?V?and ROX which is not conducive to the stability of the adsorbed solid.