镧负载纤维素水凝胶多级串联吸附柱回收二沉池出水中磷的性能及机制研究  

Multi-stage series adsorption column of La loaded cellulose-based hydrogel for phosphate recovery from secondary sediment effluent:The performance and mechanism

作　　者：李小林 王毅力[1] 刘晨阳 任立威 LI Xiaoin;WANG Yii;LIU Chenyang;REN Liwei(College of Environmental Science and Engineering,Beijing Forestry University,Beijing 100083;The Institute of Seawater Desalination and Multipurpose Utilization,Tianjin 300192)

机构地区：[1]北京林业大学环境科学与工程学院,北京100083 [2]自然资源部天津海水淡化与综合利用研究所,天津300192

出　　处：《环境科学学报》2023年第12期317-326,I0006,共11页Acta Scientiae Circumstantiae

基　　金：国家重点研发计划(No.2017YFC0505303);国家自然科学基金(No.51978054,52170122);北京市教委“生态修复工程学”高精尖学科项目(No.GJJXK210102)。

摘　　要：为了有效控制水体富营养化、降低污水处理厂出水磷浓度,采用多级串联吸附柱探究镧负载纤维素水凝胶CCH@La对二沉池出水中磷的吸附性能和机理,分析二沉池出水中共存组分对吸附和脱附过程的影响.结果表明,多级串联柱吸附装置可以有效使二沉池出水的磷浓度从2.0 mg·L^(-1)下降到0.1 mg·L^(-1)以下,初次运行的穿透体积为10182.59 BV(~50.13 mg·g^(-1)),酸洗再生可以使CCH@La的处理效果提升到13341.83 BV(~65.58 mg·g^(-1)).CCH@La对磷的动态吸附过程符合Thomas和Yoon-Nelson模型,吸附机理主要是形成无定形La–P络合物,同时Ca^(2+)会在吸附剂表面形成三元络合物≡La–P–Ca和四元络合物≡La–P–Ca–P,并在pH较高的环境下生成少量Ca5(PO4)_(3)(OH)沉淀.酸洗过程可以使吸附剂表面发生Ca5(PO4)_(3)(OH)沉淀溶解和LaPO4·0.5H_(2)O重结晶反应,从而提升吸附剂的脱附和重复利用性能.该研究可以为新型吸附剂在二沉池出水磷回收中的应用提供理论依据,为推动污水中磷酸根吸附和回收技术的发展奠定基础.In order to effectively control the eutrophication of water body and reduce the phosphate concentration in the effluent of WWTP,a multi-stage series of adsorption columns were employed to explore the adsorption performance and mechanism of secondary sediment effluent by La loaded cellulose-based hydrogel [e-mail] influence of coexisting substances in the secondary sediment effluent on the adsorption and desorption process was analyzed.The results indicated that the multi-stage series adsorption column could effectively reduce the phosphate concentration in the secondary sediment effluent from 2.0 mg·L^(-1) to below 0.1 mg·L^(-1).The initial treatment volume was 10182.59 BV(~50.13 mg·g^(-1)),and after acid washing regeneration of adsorbent,the treatment volume increased to 13341.83 BV(~65.58 mg·g^(-1)).The dynamic adsorption process of phosphate by CCH@La was well interpreted by Thomas model and Yoon-Nelson model,and the adsorption mechanism was dominated by the formation of amorphous La–P complex.At the same time,the Ca^(2+)ions could form ternary complexes≡La–P–Ca and quaternary complexes≡La–P–Ca–P on the surface of adsorbent,and generated a small amount of Ca5(PO4)_(3)(OH)precipitation in a relative high pH environment.Acid washing could dissolve the Ca5(PO4)_(3)(OH)precipitation and recrystallize LaPO4·0.5H_(2)O on the surface of the adsorbent,thereby improving the regeneration and reuse performance of the adsorbent.This study can provide theoretical basis for the application of new adsorbents in phosphate recovery from secondary sediment effluent,and lay the foundation for promoting the development of phosphate adsorption and recovery technology in wastewater.

关 键 词：吸附柱 磷回收 二沉池出水 共存组分 

分 类 号：X703[环境科学与工程—环境工程]