不同生物炭对磷的吸附特征及其影响因素

Phosphorus Adsorption Characteristics of Different Biochar Types and Its Influencing Factors

为了实现植物生物质资源化利用,选择5种生物质材料制备生物炭,通过比较5种生物炭材料的磷吸附能力,筛选出了2种磷吸附效果较佳的材料,并探明了筛选生物炭材料的理化性质及其对磷的吸附特征.结果表明,5种生物炭材料中,仅水稻秸秆和玉米秸秆生物炭对磷具有吸附能力.Langmuir等温吸附曲线表明,水稻秸秆生物炭对废水中磷的吸附能力强于玉米秸秆生物炭,理论最大吸附量为:水稻秸秆生物炭(9.78 mg·g^(-1))>玉米秸秆生物炭(0.39 mg·g^(-1)).水稻秸秆生物炭的比表面积(148.30 m^(2)·g^(-1))和总孔体积(0.11 cm^(3)·g^(-1))远高于玉米秸秆生物炭8.26 m^(2)·g^(-1)和0.03 cm^(3)·g^(-1),同时水稻秸秆生物炭有更高的Mg、Ca、Fe和Al元素含量.水稻秸秆生物炭和玉米秸秆生物炭对磷吸附的最佳pH为酸性;在不同的pH范围内(3.0~11.0),水稻秸秆生物炭对磷的吸附容量基本保持不变,玉米秸秆生物炭对磷的吸附容量呈现先增加后减少趋势.综合而言,水稻秸秆生物炭对水体磷具有更好的吸附能力,在污水处理中具有良好应用前景.

In order to understand the resource utilization of plant biomass,five types of biomass materials were used to produce biochar to treat wastewater containing phosphorus.The phosphorus adsorption capacity of five materials was preliminarily compared through laboratory experiments,and two materials with strong phosphorus adsorption capacity were screened out.The physicochemical characteristics of the selected biochar were analyzed using scanning electron microscopy and a BET specific surface area analyzer,and the effects of different pH values on phosphorus adsorption of the biochar were investigated.Furthermore,the phosphorus adsorption characteristics of the selected biochar were analyzed via isothermal adsorption and adsorption kinetics models.The results showed that among the five biochar materials,only rice straw and corn straw biochar had the ability to adsorb phosphorus.The Langmuir isothermal adsorption curve showed that the adsorption capacity of rice straw biochar for phosphorus in wastewater was stronger than that of corn straw biochar,and the theoretical maximum adsorption capacity was as follows:rice straw biochar(9.78 mg·g^(-1))>corn straw biochar(0.39 mg·g^(-1)).The specific surface area(148.30 m^(2)·g^(-1))and total pore volume(0.11 cm^(3)·g^(-1))of rice straw biochar were much higher than those of corn straw biochar(8.26 m^(2)·g^(-1) and 0.03 cm^(3)·g^(-1),respectively),and the contents of Mg,Ca,Fe,and Al were higher in rice straw biochar.The best pH for phosphorus adsorption of rice straw biochar and corn straw biochar was acidic.In different pH ranges(3.0-11.0),the phosphorus adsorption capacity of rice straw and corn straw biochar decreased with the increase in pH.These results indicated that rice straw biochar has strong phosphorus adsorption capacity and has a better application prospect in wastewater treatment.