摘要
以煤矸石和氧化钙为原料,通过热碱改性方式,制备改性煤矸石吸附剂(Ca-CG)。通过扫描电镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)方法分析证明了改性煤矸石比表面积增加,在其表面及其内部孔径中成功引入了Ca^(2+)。试验研究了氧化钙添加量和pH值对磷酸盐吸附的影响。动力学和热力学分析表明:Ca-CG吸附磷酸盐过程符合准二级动力学方程,且该过程是自发进行;在煅烧温度为1073 K,煤矸石与氧化钙比例为1∶0.5条件下,对10 mg/L磷酸盐去除率超过95%。
To improve the efficiency of phosphate removal in wastewater,a new type of gangue composite adsorbent was prepared by using three raw materials:coal gangue,calcium oxide,and sodium hydroxide,to treat simulated phosphate wastewater.SEM,EDS,XRD,FTIR were used to characterize and analyze the structure of the adsorbent before and after modification of coal gangue.The results show that the structure of coal gangue was destroyed,a large number of internal pore structures appeared,the specific surface area increased,and calcium ions were successfully introduced into the structure of coal gangue.It also creates conditions for the good phosphorus removal effect of the new adsorbent.The optimal ratio of raw materials and the factors affecting coal gangue adsorbent(including temperature,initial pH,isoelectric point,and competing ions) were discussed,and the optimal ratio was obtained(coal gangue∶calcium oxide=1∶0.5).The optimum temperature is 25 ℃,and pH and competing ions have little effect on the adsorption process.The effect of these factors on the phosphorus removal effect in the actual wastewater discharged.The adsorption mechanism was studied by kinetic and thermodynamic fitting,and the reaction mechanism of phosphorus removal by the new coal gangue adsorbent was verified.The kinetic and thermodynamic analysis shows that the process conforms to the pseudo-second-order kinetic equation,and the process is spontaneous.Based on the above analysis,when the calcination temperature is 800 ℃ and the ratio of coal gangue to calcium oxide is(1∶0.5),the adsorbent has the best effect.The phosphate removal rate exceeds 95% under the conditions of the temperature of 25 ℃,pH=7,the dosage of 10 g/L,and an adsorption equilibrium time of 30 hours.
作者
张凤娥
张坤
ZHANG Feng’e;ZHANG Kun(School of Environmental and Safety Engineering,Changzhou University,Changzhou 213164,Jiangsu,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2021年第6期2774-2780,共7页
Journal of Safety and Environment
关键词
环境工程学
煤矸石
氧化钙
磷酸盐
吸附
environmental engineering
coal gangue
calcium oxide
phosphate
adsorption
