蛋壳粉对水中酸性大红的吸附特征研究

Adsorption of Acid Scarlet G by Eggshell Powder from Aqueous Solution

采用扫描电镜、激光衍射粒度分析仪和比表面积及孔径分析仪对蛋壳粉(Eggshell powder,ESP)的表面微观结构、比表面积、孔容、孔径等进行了表征。通过静态吸附试验,研究了ESP对水中酸性大红的吸附特征和影响因子。结果表明,ESP对酸性大红的吸附过程符合Lagergren准二级动力学方程和Freundlich等温模型,是一个放热过程,不能自发进行,属物理吸附。最大吸附率为70.34%,吸附量为0.78 mg·g-1,pH和离子强度是影响吸附率的关键因素。ESP对酸性大红的吸附能力有限,可作为一种预处理方法,开发综合利用技术是扩大蛋壳资源应用前景的重要途径之一。

China is the largest producer and consumer of eggs in the world and generates 4 million tons of eggshells annually. However, the utilization rate of eggshell in China is less than 1%. Eggshells contain large amount of calcium carbonate and trace amounts of magnesium, phosphorous and other micronutrients. The uses of eggshell are receiving extensive attentions all over the world. This study was designed to explore the application of eggshells in wastewater treatments. Surface microstructure, specific surface area, pore volume and pore radius of eggshell powder（ESP） were determined using scanning electron microscope（SEM）, laser diffraction particle size analyzer and surface area and pore size analyzer, respectively. Static adsorption experiment was conducted to investigate adsorption and influencing factors of acid scarlet G by ESP from aqueous solution. Adsorption process of acid scarlet G by ESP could be well described by Lagergren pseudo-second- order kinetic equation and better fitted to Freundlich isotherm model. The negative AH~ and positive AGo revealed that the adsorption was an exothermic and physical sorption process that could not occurred spontaneously. The maximal removal rate and adsorption capacity of acid scarlet G by ESP were 70.34% and 0.78 mg g-l, respectively. Solution pH and ionic strength were the most important factors influencing the adsorption process. Overall, ESP could be an alternative adsorbent for pre-treatment of acid scarlet G although its removal rate was limited. Developing an integrated utihzation of ESP would expand applications of eggshell resources.