农业环境科学学报
農業環境科學學報
농업배경과학학보
Journal of Agro-Environment Science
2014年
9期
1817-1822
,共6页
铁改性生物炭%吸附%磷形态%pH
鐵改性生物炭%吸附%燐形態%pH
철개성생물탄%흡부%린형태%pH
Fe-modified biochar%adsorption%phosphorus forms%pH
利用农作物残体小麦秸秆为原料制备生物炭，并用氯化铁溶液改性，考察了改性后生物炭元素组成和表面官能团的变化、改性和吸附后生物炭中磷形态变化特征以及溶液初始pH的影响，分析了铁改性生物炭对磷的吸附机理。结果表明，生物炭经氯化铁溶液改性后C的质量分数大幅下降，O和Fe的质量分数大幅上升；表面的羧基含量增加，碱性官能团含量显著降低。铁改性使生物炭对磷的吸附平衡时间由改性前的60 min增至120 min；铁改性后，生物炭的理论最大吸附量为10.1 mg·g-1，是改性前的19.4倍。改性前生物炭对磷的吸附主要是物理吸附，表现为交换态磷含量大幅增加，占吸附总量的82.1%；而铁改性生物炭主要是化学吸附，表现为铁结合态磷的增幅最大，占吸附总量的66.7%，交换态磷仅占26.6%。随溶液初始pH的增加，铁改性生物炭对磷的去除率先增加后下降，pH=7时去除率最高，去除率随pH的变化与交换态磷含量密切相关；随着pH升高，铁结合态磷有向闭蓄态磷转化的趋势。
利用農作物殘體小麥秸稈為原料製備生物炭，併用氯化鐵溶液改性，攷察瞭改性後生物炭元素組成和錶麵官能糰的變化、改性和吸附後生物炭中燐形態變化特徵以及溶液初始pH的影響，分析瞭鐵改性生物炭對燐的吸附機理。結果錶明，生物炭經氯化鐵溶液改性後C的質量分數大幅下降，O和Fe的質量分數大幅上升；錶麵的羧基含量增加，堿性官能糰含量顯著降低。鐵改性使生物炭對燐的吸附平衡時間由改性前的60 min增至120 min；鐵改性後，生物炭的理論最大吸附量為10.1 mg·g-1，是改性前的19.4倍。改性前生物炭對燐的吸附主要是物理吸附，錶現為交換態燐含量大幅增加，佔吸附總量的82.1%；而鐵改性生物炭主要是化學吸附，錶現為鐵結閤態燐的增幅最大，佔吸附總量的66.7%，交換態燐僅佔26.6%。隨溶液初始pH的增加，鐵改性生物炭對燐的去除率先增加後下降，pH=7時去除率最高，去除率隨pH的變化與交換態燐含量密切相關；隨著pH升高，鐵結閤態燐有嚮閉蓄態燐轉化的趨勢。
이용농작물잔체소맥갈간위원료제비생물탄，병용록화철용액개성，고찰료개성후생물탄원소조성화표면관능단적변화、개성화흡부후생물탄중린형태변화특정이급용액초시pH적영향，분석료철개성생물탄대린적흡부궤리。결과표명，생물탄경록화철용액개성후C적질량분수대폭하강，O화Fe적질량분수대폭상승；표면적최기함량증가，감성관능단함량현저강저。철개성사생물탄대린적흡부평형시간유개성전적60 min증지120 min；철개성후，생물탄적이론최대흡부량위10.1 mg·g-1，시개성전적19.4배。개성전생물탄대린적흡부주요시물리흡부，표현위교환태린함량대폭증가，점흡부총량적82.1%；이철개성생물탄주요시화학흡부，표현위철결합태린적증폭최대，점흡부총량적66.7%，교환태린부점26.6%。수용액초시pH적증가，철개성생물탄대린적거제솔선증가후하강，pH=7시거제솔최고，거제솔수pH적변화여교환태린함량밀절상관；수착pH승고，철결합태린유향폐축태린전화적추세。
Biochar has great potential to adsorb phosphorus, and its phosphorus forms are important for phosphorus release and bioavailabili-ty. In this study, wheat straw derived biochar was used to examine the changes of elements and surface functional groups, phosphorus ad-sorption and forms in biochar after modification. Modification obviously decreased C mass fraction, but increased O and Fe mass fractions in the biochar. The content of carboxyl in biochar significantly increased, while basic functional groups decreased after modification. Modifica-tion led to the equilibrium time of phosphorus adsorption by biochar increasing from 60 min to 120 min. The maximum adsorption capacity of phosphorus by Fe-modified biochar was 10.1 mg·g-1, which was 19.4 times that of unmodified biochar. The content of exchangeable phos-phorus in unmodified biochar accounted for 82.1% of the total adsorption, suggesting that the adsorption mechanism was mainly physical adsorption. However, the content of iron-bound phosphorus in Fe-modified biochar was 66.7%of the total adsorption, while exchangeable phosphorus only 26.6%, implying that phosphorus was adsorbed by chemical adsorption. Increasing initial pH enhanced the removal per-centage of phosphorus by Fe-modified biochar until pH7, and then decreased. The pH dependence of phosphorus removal rates was closely related to the content of exchangeable phosphorus. Increased pH might promote iron-bound phosphorus transform into occluded phosphorus.
