磷酸改性生物炭负载硫化锰去除废水中重金属镉

Removal of cadmium in wastewater by phosphoric acid modified biochar supported manganese sulfide

采用磷酸作为活化剂对黍糠生物炭进行改性,得到富含活性官能团的功能性生物炭(fCBC),并将其作为硫化锰(MnS)的载体,最终成功制备出硫化锰负载的磷酸改性生物炭(MnS-fCBC),可用于水体中镉(Cd)的高效去除.系统评价了初始浓度、初始pH值以及Mn S-f CBC投加量对于吸附反应的影响.MnS-f CBC表现出优越的吸附Cd的能力,在初始Cd浓度为200mg/L、p H=6和投加量1g/L的条件下,MnS-f CBC对于Cd的吸附容量最大,达145.15mg/g.吸附反应受pH值影响显著,在偏酸性条件下能取得较好的去除效果.通过X射线衍射仪(XRD)和拉曼光谱仪(Raman)对Mn S-f CBC进行结构表征分析,结合批次试验探讨了Cd的去除机理.结果表明,表面络合和化学沉淀是Cd去除的主要机理.材料的回用性能试验显示,在5次循环使用后,材料依然有较高的Cd去除能力,表明其具有较高的可重用性.因此,MnS-f CBC可作为一种高效的Cd吸附剂,应用于含Cd废水处理.

In this study,phosphoric acid was used as an activator to modify chaff-derived biochar for the obtainment of functional chaff-derived biochar(fCBC),which was rich in active functional groups.Then fCBC was utilized as a carrier material for manganese sulfide(MnS-fCBC),which could be applied to effectively remove cadmium(Cd)in aqueous solution.The effects of initial Cd concentration,initial pH value and dosage of MnS-fCBC on the adsorption capability were systematically evaluated.The MnS-fCBC showed an excellent adsorption performance of Cd.Under the condition of the intial Cd concentration was 200mg/L,solution pH value was 6,adsorbents dosage was 1g/L,the maximum adsorption capacity of MnS-fCBC came to 145.15mg/L.The adsorption reaction was significantly affected by the pH value,and a better removal performance could be obtained under weakly acidic conditions.To characterize the structure of MnS-fCBC,X-ray diffractometer(XRD)and Raman spectroscopy(Raman)was applied,and the removal mechanism of Cd was discussed by batch experiments and characterization results,showing that surface complexation and chemical precipitation were the main mechanisms of Cd removal.Recycle tests showed that the material still had significant Cd removal capability for five successive 24h adsorption-desorption cycles,which showed that Mn S-f CBC had high reusability.Therefore,MnS-fCBC could be used as an effective Cd adsorbent for the treatment of Cd-containing wastewater.