稻杆生物炭对土壤中水铁矿的形成、转化和磷酸根、土霉素吸附的影响  

Effects of rice straw-derived biochar on the formation,transformation and adsorption of ferrihydrite in soils

作　　者：许晓琴 陈再明 黄丹 汪美贞[1] XU Xiaoqin;CHEN Zaiming;HUANG Dan;WANG Meizhen(School of Environmental Science and Engineering,Zhejiang Gongshang University,Hangzhou 310018)

机构地区：[1]浙江工商大学环境科学与工程学院,杭州310018

出　　处：《环境科学学报》2024年第3期377-386,共10页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.21976097,22276169,42107035)。

摘　　要：以稻杆为原料,通过不同温度(400、700℃)裂解制得生物炭,研究了生物炭添加对弱碱性土壤(潮土,pH=7.8)和酸性土壤(红壤,pH=5.0)的浸出液组成(溶解性硅、磷和溶解性有机碳含量)、土壤浸出液中Fe(Ⅱ)共存时水铁矿的形成(通过Fe(Ⅲ)碱性沉淀形成)和转化,以及所形成的水铁矿对代表性化合物(磷酸根和土霉素)吸附行为的影响.结果表明,潮土的弱碱性有利于生物炭中硅组分的溶出,促使土壤浸出液中Fe(Ⅲ)和Fe(Ⅱ)共沉淀过程Fe―O―Si键和水铁矿的形成,缓解水铁矿在Fe(Ⅱ)催化下向针铁矿、纤铁矿和磁铁矿的转化,使水铁矿的比表面积和土霉素吸附分别增大145%~180%和24.1%~91.1%,并通过Fe―O―Si键占据水铁矿表面使磷吸附减少17.6%~26.2%(700℃制备生物炭).红壤的弱酸性限制了生物炭中硅组分的溶出、Fe―O―Si键的形成及其对水铁矿转化和吸附的影响,但未显著改变生物炭溶解性裂解炭组分对水铁矿在Fe(Ⅱ)催化下向针铁矿转化的促进作用.生物炭的硅组分可增强土壤浸出液中水铁矿的稳定,增加土霉素的吸附并减弱磷的吸附,但其功能的发挥受土壤酸碱性的调控.In this paper,we examined the use of biochar made from rice straw(pyrolyzed at temperatures of 400℃,700℃)as a soil amendment in weak alkaline and acid soils.The weak alkaline soil,known as fluvo-aquic soil with a pH of 7.8,and the acid soil,known as red soil with a pH of 5.0,were studied.The objective was to investigate the impact of biochar on the chemical composition of soil solution extracts,the formation and transformation of ferrihydrite in the presence of Fe(II)in soil extracts,and the adsorption of the formed ferrihydrite towards phosphate and oxytetracycline.In the fluvo-aquic soil solution,the addition of biochar led to an increase in dissolved silicon content in soil extracts.It also promoted the formation of Fe―O―Si bonds and ferrihydrite in Fe(III)and Fe(II)co-precipitates,while alleviating the Fe(II)-catalyzed transformation of ferrihydrite.Furthermore,the addition of biochar increased the specific surface area and oxytetracycline adsorption of the formed ferrihydrite by 145%~180%and 24.1%~91.1%,respectively.However,it reduced phosphorus adsorption by 17.6%~26.2%(for biochar from 700℃)due to surface occupation by Fe―O―Si bonds.In the red soil,the acidic solution limited the formation of Fe―O―Si bonds and its effects on ferrihydrite transformation and adsorption,primarily due to the reduced dissolution of silicon in biochar.However,it did not significantly change the promotive effect of biochar's dissolved pyrogenic carbon components on the Fe(II)-catalyzed transformation of ferrihydrite.The silicon component of biochar enhanced the stability of ferrihydrite,increased the adsorption of oxytetracycline,and weakened the adsorption of phosphorus in soil extracts.Nevertheless,the extent of its function was regulated by the soil's acid-alkaline properties.

关 键 词：稻杆生物炭 水铁矿 硅 Fe(Ⅱ)催化转化 吸附 

分 类 号：X53[环境科学与工程—环境工程] X131.3