(沈陽化工大學(xué) 化學(xué)工程學(xué)院，沈陽 110142)
摘 要: 采用離子交換法制得檸檬酸插層MgAl水滑石吸附劑，對吸附劑進(jìn)行XRD、IR、SEM和BET表征，考察制備的吸附劑對溶液中Zn2+的吸附能力，探討吸附劑投加量、Zn2+溶液濃度、pH以及吸附溫度對Zn2+吸附率的影響，并進(jìn)行動力學(xué)和熱力學(xué)特征的研究。結(jié)果表明：吸附條件對Zn2+的吸附能力影響較大，適宜的水滑石投加量為2~3 g/L，pH以弱酸性為宜，對于Zn2+濃度不超過80 mg/L的溶液，室溫下Zn2+吸附率在60%以上，而高溫有利于提高Zn2+吸附率。吸附過程符合二級動力學(xué)模型，吸附等溫曲線可用R-P模型來描述。吸附過程能夠自發(fā)進(jìn)行，為吸熱過程。
關(guān)鍵字: 水滑石；水處理；吸附；重金屬；Zn2+；檸檬酸插層
（School of Chemical Engineering, Shenyang University of Chemical Engineering, Shenyang 110142, China）
Abstract:The citrate intercalated MgAl layered double hydroxides adsorbent was prepared by anion-exchange method. The absorbents prepared were characterized by XRD, IR, SEM, BET and used to adsorb Zn2+ from aqueous solutions. The effects of adsorbent dosage, initial Zn2+ concentration, pH, adsorption temperature on the Zn2+ adsorption rate were investigated. The thermodynamics and kinetics characters were discussed. The results show that the adsorption capacity for Zn2+ is affected by adsorption conditions. The suitable adsorbent dosage is 2-3 g/ L, and pH is weak acidity. Under the above conditions, Zn2+ adsorption efficiency is over 60% at the Zn2+ concentration less than 80 mg/ L, and high temperature is benefit to improve Zn2+ adsorption rate. Adsorption process conforms to the secondary kinetics model, and the isothermal adsorption curve can be described by R-P model. The adsorption process is spontaneous and endothermic.
Key words: hydrotalcite; water treatment; adsorption; heavy metal; Zn2+; citrate intercalation
