摘要
以花生壳为生物炭质(P-BC)原料,Zn Cl2为活化剂,采用化学活化法制备生物炭质吸附剂(Z-BC),并以其吸附水中的硝基苯,考察了p H值、吸附剂投加量和吸附时间等因素对Z-BC吸附硝基苯过程的影响。分别采用吸附动力学模型和吸附等温模型对吸附动力学和等温线进行了系统分析。结果表明:p H值对吸附的影响不大,吸附剂适宜投加量为2 g·L-1,吸附平衡时间为120 min;Z-BC对硝基苯的吸附动力学过程用准一级动力学模型能很好地描述,其计算平衡吸附量与实验值相符;颗粒内扩散模型表明,吸附过程受液膜扩散与颗粒内扩散联合控制,并以颗粒内扩散为主要速率控制步骤;Langmuir吸附等温模型能更好地描述硝基苯在Z-BC上的吸附平衡;吸附热力学方程计算得到吸附焓变(ΔH)<0、吸附自由能变(ΔG)<0和吸附熵变(ΔS)>0,表明Z-BC对水中硝基苯的吸附为放热和熵值增加的自发过程。
By using ZnC12 as an activation agent, a biochar adsorbent （Z-BC） was prepared from peanut shell （P-BC） , and used to adsorb nitrobenzene from aqueous solution. The influences of the initial pH value, ad- sorbent dosage, and adsorption time on the adsorption process were investigated. The adsorption kinetics and iso- therms were systematically analyzed using adsorption kinetics models and isotherm models, respectively. The re- suits showed that the initial pH value displayed negligible effects on the adsorption process. The adsorbent suit- able dosage and adsorption equilibrium time were 2 g ~ L-1 and 120 minutes, respectively. The analysis of the kinetic parameters revealed that the pseudo-first-order model provided the best correlation to the data, and that the equilibrium adsorption capacity measured was consistent with the model calculation. The adsorption reaction rate was controlled by liquid membrane diffusion and intraparticle diffusion, and the intraparticle diffusion was the main rate-controlling step for the adsorption of nitrobenzene on Z-BC. The adsorption of nitrobenzene on Z- BC was better described by the Langmuir isotherm model. The thermodynamic analysis results revealed an en- thalpy （△H） 〈 0,a Gibbs free energy （△G） 〈 0, and entropy （△S） 〉 0, which suggested that the adsorption of nitrobenzene on Z-BC was an exothermic,spontaneous, and entropy favored nrocess.
出处
《环境工程学报》
CAS
CSCD
北大核心
2016年第9期4719-4725,共7页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(21103095)
福建省自然科学基金面上项目(2016J01068)
福建省教育厅科技重点项目(JA14273)
关键词
花生壳
生物炭质
硝基苯
吸附动力学
等温吸附
热力学
peanut shell
biochar adsorbent
nitrobenzene
adsorption kinetics
isothermal adsorption
ther-modynamics
