生物炭/壳聚糖复合材料对磷的吸附研究

Study on adsorption of phosphorus by biochar/chitosan composite

因磷所造成的水体富营养化已成为全球环境问题,水体富营养化防治关键是降低水体中磷的含量。吸附法对环境友好,不会造成二次污染,具有吸附速率快的特点。通过使用秸秆来源的生物炭作为原材料,制备生物炭/壳聚糖复合型吸附剂去除水中磷酸盐。结果表明:在磷初始浓度为25 mg/L,投加量为0.1 g、pH为5条件下,生物炭与壳聚糖质量比为4时有较大的平衡吸附容量。吸附动力学实验结果表明磷吸附过程符合准一级动力学模型;吸附热力学分析表明:吸附过程为自发反应,升高温度有利于吸附并且反应向着熵增方向进行;红外光谱、扫描电镜以及XRD表征来看,磷被吸附机理是Al^(3+)与磷相互作用产生了共沉淀现象。

Algal bloom caused by phosphorus has become a global environmental problem.The key to algal bloom control is to reduce the content of phosphorus in water.The adsorption method is environmentally friendly,does not cause secondary pollution,and has the characteristics of fast adsorption rate.In this paper,biochar from straw was used as raw material to prepare biochar/chitosan composite adsorbent to remove phosphate from water.The results showed that when the initial concentration of phosphorus was 25 mg/L,the dosage was 0.1 g,and the pH was 5,the biochar/Chitosan mass ratio was 4,the adsorption capacity was larger.The experimental results of adsorption kinetics show that the adsorption process is more in accordance with the quasi-first-order kinetic model of phosphorus adsorption,and the adsorption thermodynamics analysis shows that the adsorption process is a spontaneous reaction,and the increase of temperature is beneficial to the adsorption,the mechanism of phosphorus adsorption is that Al^(3+)reacts with phosphorus to produce co-precipitation,which is characterized by IR,SEM and XRD.