厌氧发酵对废弃钙基生物炭制备温度的影响及对水体中除磷研究

Effect of anaerobic fermentation on the preparation of calcium-contained biochar and its phosphate removal performance

水体中磷的高效去除是降低水体富营养化的有效手段.以废弃蛋壳为碳酸钙源,以厨余垃圾为生物质,采用厨余垃圾和蛋壳混合厌氧发酵进行预处理,制备钙改性生物炭(ES-BC),并用于水体中磷的去除.结果表明,当m(厨余垃圾)∶m(蛋壳)=3∶1,发酵温度为55℃,发酵7 d天后,在600℃条件下煅烧可制得除磷性能优异的ES-BC;发酵过程产生的有机酸可促进碳酸钙的预分解,进而降低后续材料的煅烧温度,保持生物炭良好的孔隙结构,有利于钙的分散和磷的去除;在较优条件下制得的ES-BC复合材料对不同浓度(1~100 mg·L^(-1))的磷污染液均具有较好的去除效果,反应产物主要包括Ca_(5)(PO_(4))_(3)OH、Ca_(10)(PO_(4))_(6)OH_(2)(HAP)和Ca_(8)H_(2)(PO_(4))_(6)·H_(2)O(OCP)等.

Efficient removal of phosphate from water is an effective method to relieve water eutrophication.In this study,eggshell and kitchen waste were selected as the calcium carbonate source and biomass respectively,and calcium modified biochar(ES-BC)was prepared through pyrolysis,with a pre-treatment of the two wastes by anaerobic fermentation.Then ES-BC composites were used to remove phosphate from water.The results showed that with the mass ratio of kitchen waste∶eggshell of 3∶1 and the fermentation temperature of 55℃,after 7 days of fermentation,the ES-BC calcined at 600℃had excellent removal performance for phosphate.The organic acids produced by anaerobic fermentation can promote the pre-decomposition of calcium carbonate,and further reduce the pyrolysis temperature of the biochar.And the relatively lower pyrolysis temperature can maintain the better pore structure of the biochar,which was conducive to the calcium dispersion on the biochar and the removal of phosphate.The prepared ES-BC can effectively remove phosphate from water at different concentrations(1~100 mg·L^(-1)),and the reaction products mainly includedCa_(5)(PO_(4))_(3)OH、Ca_(10)(PO_(4))_(6)OH_(2)(HAP) and Ca_(8)H_(2)(PO_(4))_(6)·H_(2)O(OCP),etc.