摘要
生物炭及其改性材料由于具有较发达的比表面积和孔隙结构、丰富的表面官能团及较强的吸附能力等特性,被作为良好的环境修复材料而成为农田土壤重金属污染修复领域的研究热点.选取稻壳生物炭,采用K3PO4、KMnO4和NaOH进行改性处理,利用扫描电镜(SEM)和红外光谱(FT-IR)等对生物炭表面微观形态与结构进行表征分析,并开展了90 d土壤培养试验,比较分析3种改性生物炭对冶炼厂周边农田复合重金属污染土壤中Cd和Cu的有效性和形态的影响.结果表明,改性后生物炭表面粗糙,比表面积和孔容均有不同程度的增大,其中,NaOH改性生物炭变化最为明显,分别由改性前的4.96 m^(2)·g^(-1)和0.02 cm^(3)·g^(-1)增至60.79 m^(2)·g^(-1)和0.12 cm^(3)·g^(-1),孔径变化则与之相反;改性生物炭的官能团吸收特征峰值均发生改变,其中K3PO4改性生物炭的变化最为明显.添加不同改性生物炭均能显著提高土壤pH值(P<0.05),K3PO4改性生物炭对土壤pH的增幅最大,为20.5%;K3PO4改性生物炭对土壤中Cu和Cd的有效态含量的影响也最为明显,分别降低了75.44%和67.70%;土壤中Cu和Cd的水溶态、可交换态和碳酸盐结合态比例均降低,其中K3PO4改性生物炭对Cu和Cd的钝化效果最好,添加量为2%时,钝化效率分别为61.06%和4.12%,Cu的钝化效率远高于Cd.综上所述,K3PO4改性生物炭对复合污染土壤中Cu和Cd具有较强的钝化效果.
Heavy metals in farmland soil are one of the most hazardous pollutants in the environment,owing to their universality and irreversibility. Modified biochar has been widely used in the adsorption and immobilization of heavy metals in soil,and its applicability is mainly determined by the types of heavy metals,pollution levels,and soil environmental conditions. Soil pollution is gradually becoming more complex and diversified,and heavy metal pollutants mostly occur in the form of compound pollution. However,most studies have focused on single heavy metal pollutant or the addition of heavy metal to soil. This study used rice straw as a raw material to prepare biochar,and modified it with K3PO4,KMnO4,and NaOH. The physicochemical and structural characteristics of the modified biochars were detected using a BET accelerated surface area and porosimetry system,scanning electron microscopy( SEM),Fourier transform infrared spectroscopy( FT-IR),and the biochars were then analyzed for the availability and forms of Cd and Cu in soils contaminated with heavy metals in the mining area. The results showed that the surface roughness of the modified biochar increased to different degrees with increases in specific surface area and pore volume,with the NaOH modified biochar showing the most significant increases from 4. 96 m^(2)·g^(-1) to 60. 79 m^(2)·g^(-1),and from 0. 02 cm^(3)·g^(-1) to 0. 12 cm^(3)·g^(-1),respectively. The pore diameter changed in the opposite direction. The absorption peaks of the functional groups of the modified biochar were all changed,with K3PO4 modified biochar exhibiting the greatest degree of change. The addition of biochar significantly improved the soil pH value( P < 0. 05),and the pH value of the soil treated with K3PO4 modified biochar exhibited the largest increase. With an application of 20. 5% K3PO4 modified biochar,the availability of Cu and Cd in the soil was significantly reduced,by 75. 44% and 67. 70%,respectively. The immobilization efficiency of Cu was much higher than that of Cd. The
作者
王鑫宇
孟海波
沈玉君
王佳锐
张曦
丁京涛
周海宾
李春燕
程琼仪
WANG Xin-yu;MENG Hai-bo;SHEN Yu-jun;WANG Jia-rui;ZHANG Xi;DING Jing-tao;ZHOU Hai-bin;LI Chun-yan;CHENG Qiong-yi(Academy of Agricultural Planning and Engineering,Ministry of Agriculture and Rural Affairs,Beijing 100125,China;Key Laboratory of Technology and Model for Cyclic Utilization from Agricultural Resources,Ministry of Agriculture and Rural Affairs,Beijing 100125,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2021年第9期4441-4451,共11页
Environmental Science
基金
国家重点研发计划项目(2018YFD0500205)。
关键词
改性生物炭
特性表征
农田土壤重金属
有效性
形态分配
modified biochar
structural characteristics
heavy metals in farmland soil
availability
form distribute
