Binh Quach An, Kajitvichyanukul Puangrat
Center of Excellence on Environmental Research and Innovation, Faculty of Engineering, Naresuan University, Phitsanulok 65000, Thailand E-mail:
Water Sci Technol. 2019 Mar;79(5):866-876. doi: 10.2166/wst.2018.529.
The adsorption mechanism of dichlorvos onto coconut fibre biochar (CFB) was investigated by the batch adsorption technique. Coconut fibre waste material was synthesised at 600 °C for 4 h under oxygen-limited conditions. The biochar was modified by HCl acid to enhance the specific surface area and porosity. The characteristics of the biochar were analysed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area, and Fourier transform-infrared (FT-IR). The results showed that the BET specific surface area of biochar was 402.4 m/g. Experimental data presented a good fit to Langmuir isotherm and the pseudo-second-order model. Langmuir isotherm illustrated that monolayer adsorption of dichlorvos occurred on the surface of CFB, with a maximum adsorption capacity of 90.9 mg/g. The diffusion model confirmed that the liquid film diffusion was the rate-limiting step, and the major diffusion mechanism of dichlorvos onto biochar. The BET result after dichlorvos adsorption demonstrated that pore-filling occurred and occupied 58.27%. The pore-filling and chemical interactions, performed important roles in the adsorption of dichlorvos onto CFB. Chemical adsorption is comprised of two interactions, which are hydrophobic and H-bonding, but the prime is H-bonding. CFB is a very potential material for the removal of dichlorvos and environmental pollutants.
采用批量吸附技术研究了敌敌畏在椰壳纤维生物炭（CFB）上的吸附机制。椰壳纤维废料在600℃、限氧条件下合成4小时。生物炭用盐酸改性以提高比表面积和孔隙率。通过扫描电子显微镜（SEM）、布鲁诺尔-埃米特-泰勒（BET）比表面积和傅里叶变换红外光谱（FT-IR）对生物炭的特性进行了分析。结果表明，生物炭的BET比表面积为402.4 m²/g。实验数据与朗缪尔等温线和伪二级模型拟合良好。朗缪尔等温线表明，敌敌畏在CFB表面发生单层吸附，最大吸附容量为90.9 mg/g。扩散模型证实液膜扩散是限速步骤，也是敌敌畏在生物炭上的主要扩散机制。敌敌畏吸附后的BET结果表明发生了孔隙填充，孔隙填充率为58.27%。孔隙填充和化学相互作用在敌敌畏在CFB上的吸附中起重要作用。化学吸附由疏水作用和氢键作用两种相互作用组成，但主要是氢键作用。CFB是一种去除敌敌畏和环境污染物的极具潜力的材料。
