柠檬酸改性竹纤维吸附剂的制备

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Ni2+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Ni2+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。

Preparation of bamboo fibers adsorbent modified by citric acid

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-1 CA/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-1 and 9.486 mg·g-1, respectively.