共热解法制备方解石/生物炭复合材料及其吸附Pb(II)性能和机制  

Preparation of calcite/biochar composite by co-pyrolysis and its adsorption properties and mechanism for Pb(II)

作　　者：王申宛 钟爽[1] 郑丽丽[1] 艾斌凌[1] 校导 郑晓燕[1] 杨旸 盛占武[1] Shenwan WANG;Shuang ZHONG;Lili ZHENG;Binling AI;Dao XIAO;Xiaoyan ZHENG;Yang YANG;Zhanwu SHENG(Haikou Experimental Station,Chinese Academy of Tropical Agricultural Sciences,Haikou 571101,China;College of Food Science and Engineering,Hainan University,Haikou 570228,China)

机构地区：[1]中国热带农业科学院海口实验站,海口571101 [2]海南大学食品科学与工程学院,海口570228

出　　处：《复合材料学报》2021年第12期4282-4293,共12页Acta Materiae Compositae Sinica

基　　金：海南省自然科学基金(319QN267);中央级公益性科研院所基本科研业务费创新团队专项(17CXTD-05);海南省重点研发计划(ZDYF2019187)。

摘　　要：为了制备一种高效吸附含Pb(II)废水的生物炭材料,以椰壳(CS)和方解石(CAL)为原料,采用共热解法分别在500℃、600℃、700℃制备了方解石/生物炭(CAL/BC)复合材料。通过SEM、ICP-MS、BET、XRD、FTIR等方法对CAL/BC复合材料的表面微观形态和结构进行了表征。结果发现,三种热解温度条件下,CAL均能够与CS紧密结合,而且CAL/BC具有较大的比表面积,表面含有丰富的官能团。批量吸附实验结果表明,CAL和CS质量比为1∶2,pH值为5.5,吸附剂添加量为1.5 g·L^(−1),此时CAL/BC复合材料对Pb(II)的吸附量分别为95.24 mg·g^(−1)(500℃)、99.01 mg·g^(−1)(600℃)、185.19 mg·g^(−1)(700℃),可见热解温度为700℃时,吸附效果最佳。吸附过程符合二级动力学模型和Langmuir等温线模型。CAL/BC复合材料吸附Pb(II)的主要机制是沉淀、离子交换、阳离子-π作用、孔隙填充和静电引力。此外,CAL/BC复合材料在4次吸附-解吸循环后仍能保持较高的Pb(II)去除率。因此,共热解法制备的CAL/BC复合材料在处理废水中的Pb(II)方面具有广阔的应用前景。In order to obtain a biochar material which adsorbs PB(II)in wastewater efficiently,calcite/biochar(CAL/BC)composite was prepared by co-pyrolysis at 500℃,600℃and 700℃,using coconut shell(CS)and calcite(CAL)as raw materials.The surface morphology and structure of CAL/BC composites were characterized by SEM,ICP-MS,BET,XRD and FTIR.The results show that CAL and CS combine tightly under the three pyrolysis tempera-tures,and CAL/BC has a large specific surface area and a large number of functional groups.The maximum adsorption capacities of PB(II)on CAL/BC composite(CAL∶CS=1∶2,mass ratio)prepared at 500℃,600℃,and 700℃are 95.24 mg·g^(−1),99.01 mg·g^(−1),and 185.19 mg·g^(−1).The optimum adsorption condition is pH=5.5 and the amount of adsorbent is 1.5 g·L^(−1).The adsorption process conforms to the second-order kinetic model and Langmuir isotherm model.The mechanisms of adsorption of Pb(II)on CAL/BC composites are precipitation,ion exchange,cation-πaction,pore filling and electrostatic gravitation.In addition,the removal rate of Pb(II)by CAL/BC composite remains high level after 4 adsorption-desorption cycles.Therefore,the CAL/BC composite prepared by co-pyrolysis has a excellent application prospect in the treatment of Pb(II)in wastewater.

关 键 词：方解石 椰壳 生物炭 复合材料 PB(II) 吸附 

分 类 号：TB332[一般工业技术—材料科学与工程]