MgO改性莲蓬壳生物炭的制备及其磷吸附特性

Preparation of MgO Modified Lotus Shell Biochar and Its Phosphorus Adsorption Characteristics

为了研究生物炭作为磷吸附剂的潜在应用特性,本文通过将MgO与莲蓬壳混合物快速热解制备纳米MgO-生物炭吸附剂.采用XRD、BET、SEM和TEM对其理化特性进行表征,并进行了吸附实验.结果表明,MgO主要以薄片状和颗粒状的形态负载在炭表面,使吸附活性位点增加,MgO-生物炭MBC3吸附量是未负载MgO生物炭MBC1的14倍,热解通10%CO2载气,MBC9的吸附量进一步增加为MBC1的16倍.准二级动力学能更好地描述吸附过程,磷酸根在MgO-生物炭上的吸附是以化学吸附为主导.MBC3和MBC9的Langmuir最大吸附量分别可达到283.26 mg·g^-1和297.96 mg·g^-1.MgO-生物炭是一种高效的磷吸附剂,可用来治理水体富营养化问题.

To study the potential application characteristics of biochar as a phosphate adsorbent,nano-MgO-biochar was prepared by rapid pyrolysis of a mixture of MgO and lotus shells.The physicochemical properties were characterized by XRD,BET,SEM,and TEM,and adsorption experiments were conducted.The results showed that MgO was mainly supported on the surface of carbon in the form of flakes and granules,which increased the adsorption active site,and the adsorption amount of MgO-biochar MBC3 was 14 times higher than that of biochar MBC1 without MgO.The adsorption capacity of MBC9,which was prepared by rapid pyrolysis under 10%CO2 atmosphere,was further increased 16 times higher than that of MBC1.The adsorption kinetics followed a pseudo-second-order model,which indicated the adsorption of phosphate on MgO-biochar was dominated by chemical adsorption.According to the Langmuir equation,the maximum adsorption capacity of MBC3 and MBC9 could reach 283.26 mg·g^-1 and 297.96 mg·g^-1,respectively.MgObiochar is a high-efficiency phosphate adsorbent,which can be used to control the eutrophication of water.