猕猴桃木生物质炭对溶液中Cd2+、Pb2+的吸附及应用研究

Application of biochar derived from kiwi pruning branches for Cd2+ and Pb2+ adsorption in aqueous solutions

为探讨生物质炭对废水中重金属的吸附性能,以猕猴桃修剪枝为原料制备生物质炭,通过静态吸附法研究了其对复合溶液中Cd^2+、Pb^2+的吸附,探究了溶液初始浓度、吸附时间、pH值及生物质炭投加量对溶液中Cd^2+、Pb^2+吸附效果的影响,同时采用扫描电镜(SEM)和傅里叶红外光谱(FTIR)对吸附前后的生物质炭结构进行了表征,并讨论了其对养殖废水和垃圾渗滤液中Cd^2+和Pb^2+的吸附能力。结果表明:猕猴桃木生物质炭具有多孔结构和多种表面官能团。Cd^2+、Pb^2+的最优吸附条件是pH为4~6,120 min吸附达到平衡,最佳投加量分别为4.0、3.0 g·L^-1,最大吸附量分别为9.35、65.9 mg·g^-1。生物质炭对Cd^2+、Pb^2+的吸附过程用准二级动力学方程能较好地描述;在25℃条件下,生物质炭对Cd^2+的吸附用Langmuir方程能更好地描述,其理论最大吸附量达13.1 mg·g^-1,而生物质炭对Pb^2+的吸附过程用Freundlich方程能更好地描述。猕猴桃木生物质炭可作为处理轻度重金属复合污染废水的吸附剂。

This research aims to investigate the effect of biochar derived from kiwi pruning branches on Cd^2+and Pb^2+in aqueous solutions.The affecting factors including initial concentration,adsorption time,initial pH,and sorbent dosage were investigated in batch experiments.The adsorption capacity of biochar for Cd^2+and Pb^2+from aquaculture wastewater and landfill leachate was tested.The biochar before and after adsorption was characterized using scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR).The results indicated that kiwi pruning branches biochar had high porous structure and abundant surface functional groups.The optimal conditions for Cd^2+and Pb^2+adsorption were pH 4~6 with 120 min contact time(reached equilibrium).The optimal sorbent dosages were 4.0 g·L^-1 for Cd^2+and 3.0 g·L^-1 for Pb^2+,and the maximal adsorption capacity was recorded at 9.35 and 65.9 mg·g^-1,respectively.Additionally,Cd^2+and Pb^2+adsorption onto biochar followed a pseudo second order model.The adsorption characteristics of Cd^2+were well described by the Langmuir equation with a theoretical maximum adsorption capacity of 13.1 mg·g^-1,whereas the Freundlich equation was more appropriate for Pb^2+adsorption.Overall,the kiwi pruning branches biochar shows higher adsorption performance and potential application in Cd^2+and Pb^2+removal from wastewater.