钴铁层状双金属负载生物炭对水体硝氮的吸附研究

Study the Adsorption of Nitrate in Water by Cobalt⁃Iron Layered Bimetal⁃Loaded Biochar

水体中的硝氮质量浓度不断升高,对水生态系统和人类健康存在潜在威胁。因此,解决水体中过量硝氮的问题刻不容缓。以Fe(NO_(3))_(3)·9H_(2)O、Co(NO_(3))_(2)·6H_(2)O、芦苇生物炭、NH_(3)·H_(2)O为原料,采用共沉淀法将钴铁层状双金属负载到芦苇生物炭上,制备了可用于吸附水体中过量硝氮的Co/Fe-LDH@BC。结果表明,Co/FeLDH@BC可有效吸附水体中的硝氮,其吸附量为88.52 mg/g;吸附动力学模型符合伪二级动力学模型,等温线符合Langmuir等温线模型,说明吸附反应为自发的、吸热的,主要涉及离子交换、配体交换、静电吸引、氢键四种反应机理;Co/Fe-LDH@BC在大多数共存阴离子的水体中对硝氮具有很强的亲和力,具有实际应用价值。

Rising levels of nitrate and nitrogen in water bodies pose a potential threat to aquatic ecosystems and human health.Therefore,it is urgent to solve the problem of excessive nitrate in water bodies.Fe(NO_(3))_(3)·9H_(2)O,Co(NO_(3))_(2)·6H_(2)O,reed biochar,NH_(3)·H_(2)O was used as raw material,and co⁃precipitation method was used to load cobalt⁃iron layered bimetals onto reed biochar to prepare Co/Fe⁃LDH@BC for adsorption of excess nitrate nitrogen in water.The experimental results showed that Co/Fe⁃LDH@BC could effectively adsorb nitrate nitrogen in water,and its adsorption capacity was 88.52 mg/g.The adsorption kinetic model conforms to the pseudo⁃second⁃order kinetic model,and the isotherm conforms to the Langmuir isotherm model,indicating that the adsorption reaction is spontaneous and endothermic,which mainly involves four reaction mechanisms:ion exchange,ligand exchange,electrostatic attraction and hydrogen bonding.In addition,Co/Fe⁃LDH@BC has a strong affinity for nitrate nitrogen in most water bodies where coexisting anions are present,making it suitable for practical applications.