铁改性赤泥吸附剂的制备及其除砷性能研究

以氧化铝生产废渣--赤泥为原料,采用铁盐改性处理制备了新型羟基铁包覆型赤泥除砷吸附剂.研究考察了吸附剂吸附砷效能、投加量、吸附时间和pH值对吸附除砷效果的影响;采用扫描电镜(SEM)、红外光谱(IR)、比表面积(BET)等仪器对吸附剂进行了表征,并探讨了吸附机制.结果表明,铁盐改性赤泥吸附剂对As(V)具有显著吸附效能,在pH为7,初始砷浓度为1 mg·L-1,铁盐改性赤泥吸附剂饱和吸附容量为50.6mg·g-1时,除砷率高达99.9%,吸附后出水砷含量可达到0.01 mg·L-1以下,吸附规律符合Langmuir等温方程式;溶液pH值显著影响砷去除效果,吸附机制主要为羟基铁的表面吸附机制;吸附后的吸附剂可通过NaOH溶液再生,脱附率达到92.1%.

Preparation of Fe modified red mud and its adsorption characteristics of arsenate

An effective adsorbent for arsenate removal from aqueous system was synthesized by loading iron(III) oxide on red mud(RM) which was a waste tailing from alumina production.The arsenate removal efficiency of modified red mud(MRM) was investigated.Adsorption of arsenate on MRM was studied as a function of dosage,time and pH.The modified red mud(MRM) was characterized using scanning electron microscopy(SEM) microanalysis,specific surface area(BET) and Infrared Spectra Reports(IR).The adsorption efficiency of arsenate could exceed 99.9% and adsorption capacity of MRM was found to be 50.6 mg·g^-1 with reaction conditions pH=7 and initial arsenate concentration was 1 mg·L^-1.The arsenate concentration after adsorption was below 0.01mg·L^-1.The Langmuir isotherm was the best-fit adsorption isotherm model for the experimental data.Solution pHsignificantly affected the adsorption and the function mechanism of adsorption was surface complexation.MRMcould be regenerated with NaOH,and the regeneration efficiency reached 92.1% when the concentration of NaOH was 0.2 mol·L^-1.