Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catal...Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.展开更多
文摘Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.
文摘为了改进碱木质素羟甲基化的制备方法,采用水热法对碱木质素(Lig)进行羟甲基化改性,利用FT-IR半定量法测得的羟甲基含量作为参考指标,并结合产率,确定了最佳工艺条件为:反应温度100℃、反应时间2 h、m(Lig)∶m(HCHO)为6∶1,m(Lig)∶m(NaOH)为24∶1,该工艺条件下所得羟甲基化木质素(Lig—OH)的羟甲基相对含量为0.95,比改性前Lig增加了0.27,产率为98.3%。核磁共振氢谱(1 H NMR)与热失重(TGA)的分析结果表明Lig—OH的羟甲基含量和酚羟基均有所提高,且其初始降解温度(t 5%)较Lig提高了38℃,500℃下的残留量更是提高了33.6%,所得羟甲基化木质素表现出良好的热稳定性能和成炭能力,有望作为成炭剂用于膨胀型阻燃高分子材料领域。
