Phosphoric acid pretreatment enhances the specific surface areas of biochars by generation of micropores
Phosphoric acid pretreatment enhances the specific surface areas of biochars by generation of micropores
复制标题
磷酸预处理通过产生微孔提高生物炭的比表面积
DOI：
10.1016/j.envpol.2018.04.003
复制
发表时间：
2018-09-01
影响因子：
8.9
通讯作者：
Steinberg, Christian E. W.
中科院分区：
文献类型：
--
作者：
Chu, Gang;Zhao, Jing;Steinberg, Christian E. W.
生物炭在土壤中的应用越来越多，用于固碳、提高肥力以及修复污染。磷酸(H3PO4)预处理法是生物炭的一种改性方法，但其机理尚不完全清楚。在本工作中，生物炭和生物质原料在热解前用H3PO4处理。由于酸催化和交联剂的作用，经H3PO4处理后的颗粒微孔明显增多，比表面积显著增大。结晶纤维素(CL)比无定形木质素(LG)在形成微孔方面表现出更大的优势。微孔的形成机理是：(A)H3PO4中的H+有助于通过H+催化过程生成微孔；(B)有机磷酸桥通过磷酸自由基交联来保护碳骨架免于微孔坍塌。H3PO4改性后，其对卡马西平(CBZ)和双酚A(BPA)的吸附容量增加，这归因于其具有较大的疏水比表面积和丰富的微孔。总体而言，H3PO4预处理制得的生物炭具有较大的比表面积和较高的孔结构丰度。此外，H3PO4改性生物炭既可用作高吸附材料，又可用作富磷肥料。(C)2018爱思唯尔有限公司。保留所有权利。
Biochars are being increasingly applied in soil for carbon sequestration, fertility improvement, as well as contamination remediation. Phosphoric acid (H3PO4) pretreatment is a method for biochar modification, but the mechanism is not yet fully understood. In this work, biochars and the raw biomass were treated by H3PO4 prior to pyrolysis. Due to an acid catalysis and crosslink, the micropores of the pretreated particles were much more than those without H3PO4 pretreatment, resulting in the dramatical enhancement of specific surface areas of the pretreated particles. Crystalline cellulose (CL) exhibited a greater advantage in the formation of micropores than of amorphous lignin (LG) with H3PO4 modification. The formation mechanisms of micropores were: (a) H+ from H3PO4 contributes to micropores generation via H+ catalysis process; (b) the organic phosphate bridge protected the carbon skeleton from micropore collapse via the crosslinking of phosphate radical. The sorption capacities to carbamazepine (CBZ) and bisphenol A (BPA) increased after H3PO4 modification, which is ascribed to the large hydrophobic surface areas and more abundant micropores. Overall, H3PO4 pretreatment produced biochars with large surface area and high abundance of porous structures. Furthermore, the H3PO4 modified biochars can be applied as high adsorbing material as well as P-rich fertilizer. (C) 2018 Elsevier Ltd. All rights reserved.