柠檬酸改性竹纤维吸附剂的制备

Preparation of bamboo fibers adsorbent modified by citric acid

采用预处理和柠檬酸酯化反应2个阶段的处理方法对竹纤维进行修饰改性,考察了预处理溶液浓度、预处理时间、柠檬酸用量比、催化剂用量比、热反应时间,热反应温度对改性效果的影响,并测定了改性后竹纤维材料对重金属Ni^(2+)的吸附性能。实验结果表明,当预处理溶液浓度取5%,预处理时间控制在180 min,柠檬酸用量比取20 mmol·g^(-1),催化剂次磷酸钠用量比取0.4,热反应时间控制在90 min,热反应温度为120℃时,改性效果达到最佳,得到的最高羧基团含量为3.373 mmol·g^(-1)。改性后的竹纤维材料对Ni^(2+)的吸附容量高达9.486 mg·g^(-1),相比未改性的竹纤维,吸附性能上有显著提升。

Bamboo fiber,a highly efficient absorbing material,was modified by pretreatment and esterification with citric acid. The parameters that affect the carboxyl group content and adsorption capacity of Ni2＋ions,such as the pretreatment solution concentration,pretreatment time,catalysts/bamboo weight ratio,CA/bamboo amount ratio,reaction temperature,and reaction time were examined. The experimental results showed that the optimum modified conditions were 5% pretreating solution concentration,180 min pretreatment time,20 mmol·g-1CA/bamboo amount ratio,40% sodium hypophosphite,90 min reaction time,and 120 ℃ reaction temperature. The products in the above-mentioned modified conditions showed significantly increased adsorption capacity,with the carboxyl group content and the maximum adsorption capacity being 3. 373 mmol ·g-1and 9. 486 mg ·g-1,respectively.