【摘要】 以廉价的低品位铝矾土为原料,以偏铝酸钠为补充铝源,以碳酸钠为活化剂,采用碱熔融-水热法合成了A型分子筛,考察了水热条件对所制分子筛的影响,发现SiO2/Al2O3,Na2O/SiO2和H2O/Na2O摩尔比及反应时间是影响产物晶型的主要因素,其最佳合成工艺条件是:反应物配比为1.5Na2O:0.5Al2O3:1SiO2:128H2O,于90oC晶化12h.另外,研究了水溶液中Cd2+离子在该分子筛上的吸附行为,考察了吸附时间、Cd2+离子浓度、溶液初始pH值以及分子筛用量对吸附行为的影响.结果表明,A型分子筛对水中Cd2+离子吸附90min时达平衡,吸附过程符合准二级动力学速率方程;溶液初始pH=6时,Cd2+离子的去除率最高,吸附等温线可以用Langmuir和Freundlich模型来描述,最大吸附容量可达161.3mg/g,最佳吸附剂用量为1.00g/L.更多还原

【Abstract】 A facile method comprised of alkali fusion activation and hydrothermal reaction was developed to synthesize high-quality crystallized zeolite A from cost-effective low-grade bauxite.Using sodium aluminate powder as an extra aluminum source and sodium carbonate as an activator,the reactant molar ratios of SiO2/Al2O3,Na2O/SiO2,and H2O/Na2O,the hydrothermal reaction time are optimized in detail.Highly crystallized phase-pure zeolite A is successfully synthesized from low-grade bauxite under the optimized experimental conditions of 1.5 Na2O:0.5 Al2O3:1 SiO2:128 H2O after hydrothermal reaction at 90 oC for 12 h.The cadmium ion removal from aqueous solutions using the as-synthesized zeolite A powders as an adsorbent was studied.The effects of contact time,solution concentration,solution pH value,and adsorbent amount on adsorption was investigated.The adsorption equilibrium could be reached very fast within 90 min.The adsorption followed a pseudo-second-order kinetic adsorption mode well.Both Langmuir and Freundlich models could fit the experimental data well at pH = 6.The maximum adsorption capacity was estimated to be 161.3 mg/g.The optimal adsorbent dosage is about 1.00 g/L.更多还原