碱激发热改性埃洛石对养猪废水中氨氮的去除

为筛选处理养猪废水氨氮的高效吸附剂,以Ca(OH)2、NaOH和KOH为碱激发剂分别制备CA-X、NA-X和K-X 3种改性埃洛石吸附剂,通过SEM和FT-IR分析其表面特征变化,并探讨其在不同投加量、pH、时间条件下的氨氮吸附特点及热力学、动力学吸附过程。结果表明,改性后CA-X、NA-X和K-X孔隙明显增多,其对氨氮的去除率均随投加量增加呈对数趋势增长。在25℃、投加量15 g/L、初始pH 8.3、接触时间120 min时,三者的最大吸附量分别为19.66、16.33和14.75 mg/g,较改性前分别提高6.8、5.7和5.1倍。Langmuir方程和准二级动力学方程最适于模拟它们对氨氮的等温吸附过程和动力学过程,吸附过程受离子交换和颗粒内扩散等环节控制。因此,3种碱-热改性埃洛石可作为潜在的去除养猪废水氨氮的吸附剂并有效再生利用。

Ammonia-nitrogen Removal from Swine Wastewater by Alkali-promoted Heated Modified Halloysites

In order to search high-efficiency adsorbents for ammonia-nitrogen treatment in swine wastewater, the Ca(OH)2, Na OH and KOH were used as alkali promoters to make three modified halloysites(CA-X, NA-X and K-X).The change of surface properties of the materials were characterized by SEM and FT-IR, their ammonia-nitrogen adsorption characteristics, thermodynamics and kinetics under different dosages, pH and durationwere studied.The results showed that, the porosity of CA-X, NA-X and K-X increased obviously after modification, and their removal rates for ammonia-nitrogen showed a logarithmic growth trend with the increase of dosage.Under the conditions of 25 ℃, dosage was 15 g/L, initial pH was 8.3 and contact time was 120 min, the maximum adsorption capacities of the three were 19.66, 16.33 and 14.75 mg/g, improved 6.8, 5.7 and 5.1 times than unmodified halloysite, respectively. The Langmuir equation and the quasi-second-order kinetic equation could simulate isothermal adsorption and kinetics processes effectively. The adsorption process was controlled by ion exchange and intraparticle diffusion. Therefore, the three modified halloysites can be feasible adsorbents of ammonia-nitrogenremoval from swine wastewaterand can be regenerated effectively.