咖啡壳吸附材料的制备及其对四环素吸附行为影响的研究

Preparation of Coffee Shell-based Adsorbing Material and Its Effect on Tetracycline Adsorption Behavior

以云南省保山地区废弃的咖啡壳为原料分别在不同的烧结温度(300℃、400℃和500℃),选用H_(3) PO_(4)、KOH、K_(2) CO_(3)对其进行活化处理,制备出不同类型的粉末状活性炭。并进一步探究不同类型的咖啡壳基活性炭对四环素(TC)吸附性能的影响。研究结果表明,在以KOH作为活化剂,且烧结温度为400℃的条件下制备的活性炭(K-400C-AC)对TC的吸附性能明显最好(当TC的初始浓度为5 mg/L时,0.1 g活性炭可以将其全部吸附)。通过拟一阶吸附动力学模型、拟二阶吸附动力学模型和Weber-Morris颗粒内扩散模型评价K-400C-AC对TC吸附速率的结果显示,该吸附过程的动力学过程能够很好的用拟二阶动力学模型拟合(R^(2)=0.999)。Weber-Morris颗粒内扩散模型证明了吸附过程的主要速度控制步骤是TC的边界层扩散和颗粒内扩散的联合作用。除此之外,Langmuir和Freundlich等温模型的拟合结果表明,K-400C对TC的吸附过程属于单分子层吸附,且K-400-AC对四环素(TC)的最大吸附量为16.49 mg/g。

Different types of Powdered Activated Carbon(PAC)was prepared by recycling of the waste coffee shell,which was collectedfrom Baoshan city,Yunnan Province.The preparation conditions of activated carbon were carried out at different sinteringtemperatures(300℃,400℃and 500℃)and three activators(H_(3) PO_(4)、KOH and K_(2) CO_(3)).Furthermore,the influence of different types of PAC on the adsorption performance of tetracycline(TC)was investigated.The results indicated that the as-prepared activated carbon(K-400C-AC)immersed with KOH and sinteredunder 400℃has the best adsorption performance for TC(when the initial concentration of TC was 5 mg/L,the adsorption efficiency of 0.1 g activated carbon could reach 100%).The pseudo-first-order model,pseudo-second-order adsorption kinetics model and Weber-Morris interparticle diffusion model were used to evaluate the adsorption process of K-400C-AC on TC.The results showed that thekinetics process could be well fitted by pseudo-second-order model(R^(2)=0.999).The Weber-Morris intraparticle diffusion model proved the main controlling step for the adsorption process was diffusion through the boundary layer and intra-particle.In addition,the fitting results of Langmuir and Freundlich isotherm model showed that the adsorption isotherm of K-400C-AC on TC was monomolecular,and the maximum adsorption amount of K-400-AC on tetracycline(TC)was 16.49 mg/g.