低磷污水的HAP诱导结晶磷回收  

Phosphorus recovery from wastewater with low phosphorus concentration by HAP induced crystallization

作　　者：何一帆 聂小保[1,2,3] 余志 陆洲[1,2,3] 易晋 金筱英 隆院男 蒋昌波 HE Yifan;NIE Xiaobao;YU Zhi;LU Zhou;YI Jin;JIN Xiaoying;LONG Yuannan;JIANG Changbo(School of Hydraulic Engineering,Changsha University of Science&Technology,Changsha 410114;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,Changsha 410114;Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control,Changsha 410114)

机构地区：[1]长沙理工大学水利工程学院,长沙410114 [2]洞庭湖水环境治理与生态修复湖南省重点实验室,长沙410114 [3]湖南省环境保护河湖疏浚污染控制工程技术中心,长沙410114

出　　处：《环境科学学报》2021年第2期566-573,共8页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.51408068);湖南省教育厅科学研究重点项目(No.18A122);湖南省重点研发项目(No.2019SK2191)。

摘　　要：为考察羟基磷酸钙(HAP)诱导结晶对低磷污水中PO^(3-)_(4)⁃P的回收效果,以污水厂尾水为研究对象,采用方解石为晶种,首先全面对比了HAP诱导结晶与均相结晶的PO34-⁃P去除效果,然后通过改变晶种粒径和投加量,研究了晶种对PO^(3-)_(4)⁃P回收的影响,并探讨了结晶反应条件对PO^(3-)_(4)⁃P回收和产物晶型的影响.结果表明:HAP诱导结晶除磷效果要优于均相结晶,当结晶体系pH不超过9.0且残余Ca^(2+)为100 mg·L^(-1)时,前者可将PO^(3-)_(4)⁃P浓度降至0.5 mg·L^(-1)左右,后者则为5.0 mg·L^(-1)左右.构晶离子的扩散过程是HAP诱导结晶的控速步骤,减小晶种粒径和增加晶种投加量有利于构晶离子的扩散,可提高结晶反应速率,进而提高HAP诱导结晶对低磷污水的适应性,使PO^(3-)_(4)⁃P回收率得到提高.对PO^(3-)_(4)⁃P浓度为1.0 mg·L^(-1)的模拟废水,晶种投加量为10 g·L^(-1)、粒径为45μm、Ca^(2+)投加量为50 mg·L^(-1)和pH=9时,在10 min的反应时间内HAP诱导结晶可获得80%以上的PO^(3-)_(4)⁃P回收率,出水PO^(3-)_(4)⁃P和pH满足GB 3838—2002的Ⅱ类标准(0.1 mg·L^(-1)).实验条件下,HAP诱导结晶产物晶型主要为HAP及其前驱物无定形态羟基磷酸钙(ACP),产物结晶度随着pH的提高和晶种粒径的减小而提高.In order to assess the feasibility of HAP induced crystallization to recover phosphorus from wastewater with low phosphorus concentration,the effluent from wastewater treatment plant is selected as a sample and the calcite is used as a seed in this study.The PO^(3-)_(4)⁃P removal performance between the homogeneous and the induced crystallization was compared firstly,and then the influence of seed on the PO^(3-)_(4)⁃P recovery efficiency was investigated by changing both the particle size and the dosage of seed.Moreover,the effects of crystallization reaction conditions on the PO^(3-)_(4)⁃P recovery efficiency and the polymorph type of crystallized products were studied.The results showed that the HAP induced crystallization outperformed the homogeneous crystallization in view of PO^(3-)_(4)⁃P recovery,the former reduced the PO^(3-)_(4)⁃P concentration to 0.5 mg·L^(-1),while the latter to 5.0 mg·L^(-1) when the solution system with pH lower than 9.0 and Ca^(2+)concentration of 100 mg·L^(-1).During the induced crystallization,diffusion process of the configuration ions was proved to be the controlling step of the crystallization rate.Decreasing seed particle size and increasing seed dosage favored the diffusion process of configuration ions,which improved the adaptability of HAP induced crystallization to low concentrated PO^(3-)_(4)⁃P wastewater,resulting in an enhancement of PO^(3-)_(4)⁃P recovery efficiency.For simulated wastewater with PO^(3-)_(4)⁃P concentration of 1.0 mg·L-1,PO^(3-)_(4)⁃P recovery efficiency of 80%was achieved within 10 min by HAP induced crystallization with seed dosage of 10 g·L^(-1),particle size of 45μm,Ca^(2+)dosage of 50 mg·L^(-1) and pH=9.0.Both the PO^(3-)_(4)⁃P concentration and the pH met the second grade of GB 3838-2002(0.1 mg·L^(-1)).HAP and its precursor,ACP,were the main polymorphs of crystallized products in the present experiments,and the crystallinity of products increased both with the increase of pH and the decrease of the seed particle size.

关 键 词：低磷污水 磷回收 羟基磷酸钙(HAP) 诱导结晶 晶种 

分 类 号：X703.1[环境科学与工程—环境工程]