摘要
从源分离尿液中回收磷既能减少城市污水中近50%的磷负荷,又可以促进磷资源的可持续循环。本研究利用物理筛分(d≤100μm)后的天然黄土颗粒作为吸附材料来回收水解尿液中的磷酸盐,重点考察了其对磷酸盐的吸附性能及该过程的作用机制。另外,还建立了吸附动力学和等温线方程,并且讨论了初始p H和接触时间对吸附过程的影响。研究结果表明,黄土颗粒对水解尿液中磷酸盐具有较强的吸附能力,初始p H是影响其对磷酸盐吸附性能的主要因素,最大吸附容量发生在初始p H为10.0时,可达到5.28mg/g。黄土颗粒吸附水解尿液中磷酸盐的主要作用机制是≡M—OH官能团与磷酸根的配位交换反应、羟基磷酸钙沉淀反应及磷酸铵镁沉淀反应,并且水解尿液中高氨氮浓度对黄土颗粒吸附磷酸盐具有促进作用。另外,该吸附过程符合伪二级(R_2~2=0.998)动力学方程且吸附规律符合Freundlich(R_F^2=0.990)等温线方程。
Source separation of human urine coupled with phosphorus(P)recovery could decrease50%of P present in wastewater and promote a sustainable recyclability and management of P resource.Inthis study,Chinese loess particle(d≤100μm)without physical or chemical modification was used asan adsorbent for adsorption and recovery of phosphate from hydrolysis urine.Batch experiments wereconducted for investigating the adsorption capacity of loess particle and the mechanisms of adsorptionprocesses.In addition,adsorption kinetics and isotherms,as well as the major influencing factors suchas initial pH and contact time were investigated.The results revealed that loess particle was acost-effective adsorbent for phosphate adsorption from hydrolysis urine under the optimal conditions.The initial pH of hydrolysis urine was the key factor for phosphate adsorption capacities of loessparticle,and the maximum phosphate adsorption capacities was5.28mg/g at an initial pH of10.0.Differing with the electrostatic repulsion of phosphate adsorption from synthetic phosphate solution onto loess particle,the processes of phosphate adsorption from hydrolysis urine onto loess particlewere mainly based on the action of inner-sphere ligand exchange between≡M-OH groups andphosphate,calcium phosphate precipitation reaction and magnesium ammonium phosphateprecipitation reaction.In addition,the presence of ammonium nitrogen in hydrolysis urine had anobvious positive effect on the adsorption of phosphate.Furthermore,the adsorption processes ofphosphate onto loess particle was well described by pseudo-second-order kinetic model(R22=0.998)and Freundlich isotherm model(RF2=0.990).
作者
蒋善庆
王晓昌
JIANG Shanqing;WANG Xiaochang(International Science & Technology Cooperation Center for Urban Alternative Water Resources Development,Xi-an 710055,Shaanxi,China;Key Lab of Northwest Water Resource,Environment and Ecology,MOE,Xi-an 710055 Shaanxi,China;School of Environment and Municipal Engineering,Xi’an University of Architecture and Technology,Xi-an 710055,Shaanxi,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2017年第7期2667-2675,共9页
Chemical Industry and Engineering Progress
基金
国家自然科学基金重点项目(50838005)
国家水体污染控制与治理科技重大专项项目(2013ZX07310-001)
关键词
黄土颗粒
吸附
配位交换
沉淀
动力学
等温线
loess particle
adsorption
ligand exchange
precipitation
kinetics
isotherm
