油页岩改性生物炭对磷酸盐的吸附特性

Phosphate adsorption characteristics of oil shale modified biochar

为解决磷回收困难和固体废弃物难处理的问题,文章以棉秆和油页岩为原料,采用共热解法制备了油页岩改性生物炭(OS-CS),利用SEM-EDS,BET,FT-IR等测试手段对其进行了理化特性分析,考察了热解温度、吸附剂用量、溶液pH值等因素对OS-CS的磷酸盐吸附性能的影响,并研究了OS-CS的吸附动力学和吸附等温线模型。研究结果表明:进过改性后,OS-CS的结构性能和表面形貌有较大改善,对磷酸盐的吸附能力有明显的提高;在投加量为4.0 g/L、溶液pH值为5.0时,OS-CS的磷酸盐最大吸附量为7.01 mg/g,是棉秆炭的2.47倍,油页岩半焦的3.52倍。OS-CS吸附磷酸盐过程主要以拟二级动力学和Langmuir等温吸附模型进行描述,吸附机理主要包括表面沉淀、配体交换和静电吸引。油页岩改性生物炭复合材料为磷酸盐的去除和固体废弃物的资源化利用提供了新思路。

This study aims to address the challenges of phosphorus recovery and solid waste treatment by preparing biochar composites(OS-CS)using a co-pyrolysis method with cotton straw stalk and oil shale as raw materials.The physicochemical properties of the biochar were analyzed using SEM-EDS,BET and FT-IR tests.The influence of pyrolysis temperature,adsorbent dosage,and solution pH on phosphate adsorption was investigated,and both the adsorption kinetics and isotherm models were studied.The results indicated that the structural properties and surface morphology of the biochar were significantly enhanced through oil shale modification,leading to a notable improvement in phosphate adsorption capacity.At an injection level of 4.0 g/L and pH5.0,the maximum adsorption capacity reached 7.01 mg/g,which was 2.47 times higher than that of cotton straw biochar and 3.52 times higher than that of oil shale char.The adsorption process followed the proposed secondary kinetics and Langmuir isothermal adsorption model,and the mechanisms involved surface precipitation,ligand exchange,and electrostatic attraction.This approach of oil shale modified biochar composites provides a novel strategy for both phosphorus removal and solid waste resource utilization.