论文部分内容阅读
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。
The biochar adsorbent (Z-BC) was prepared by chemical activation using peanut shell as bio-charcoal (P-BC) as raw material and Zn Cl2 as activator. With its adsorption of nitrobenzene in water, Value, adsorbent dosage and adsorption time and other factors on the adsorption of nitrobenzene Z-BC process. Adsorption kinetics model and adsorption isotherm model were used to systematically analyze adsorption kinetics and isotherms. The results showed that the adsorption of p-nitrobenzene by Z-BC was less than that of p-nitrobenzene, with the optimal dosage of adsorbent being 2 g · L-1 and the adsorption equilibrium time was 120 min. The adsorption kinetics of p- The kinetic model can be well described, and its equilibrium adsorption capacity is in good agreement with the experimental value. The intragranular diffusion model shows that the adsorption process is controlled by liquid film diffusion and interparticle diffusion, and intraparticle diffusion is the main rate control step. Langmuir Adsorption isotherm model can better describe the adsorption equilibrium of nitrobenzene on Z-BC. Adsorption enthalpy change (ΔH) <0, adsorption free energy change (ΔG) <0 and adsorption entropy change (ΔS) > 0, indicating that Z-BC adsorption of nitrobenzene in water is a spontaneous process of exothermic and entropy increase.