Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan.
Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan.
Environ Sci Pollut Res Int. 2018 Nov;25(31):31579-31592. doi: 10.1007/s11356-018-2958-2. Epub 2018 Sep 11.
Functionalized thuja cone carbon (FTCC) was synthesized thermochemically. It was carried out by carbonization (250 °C) and activation (320 °C), followed by surface functionalization in 0.5 M HAN (HNO and HCl) mixture and subsequent heating in HSO (95%) at 90 °C. This was used for methylene blue (MB) adsorption in single component system (SCS) and binary component system (BCS) with Cu. Maximum adsorption capacity of MB (83.4 mg/g) was achieved at pH 10 at 100 mg/L of adsorbate solution. MB and Cu adsorption onto FTCC obeyed pseudo-second-order model kinetics. Spontaneous and endothermic MB adsorption was noticed with negative Gibbs free energy change (- 6.34, - 9.20, and - 13.78 kJ/mol) and positive enthalpy change (133.91 kJ/mol). At low concentrations, Cu adsorption increased by 14 mg/g with least reduction of MB adsorption (< 4 mg/g) in BCS. Isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) support the increase in Cu adsorption in BCS. The sorption heat of MB shifted from 165.16 kJ/mol (SCS) to 150.85 kJ/mol in BCS (Temkin) and from 57.74 kJ/mol (SCS) to 50.50 kJ/mol in BCS (D-R), which supports the lower MB uptake in BCS due to decrease in sorption energy. The sorption heat of Cu is increased (148.43 kJ/mol) in the BCS than SCS (155.36 kJ/mol), which makes the equal distribution of increased bonding energies; therefore, FTCC surface sites increased the Cu uptake in the BCS. Desorption studies concluded the reusability of FTCC by 75% and 79% for MB and Cu adsorption respectively. This study recommends to determine the best fit of isotherm and kinetic models to adsorption data by linear as well as nonlinear regression fit.
功能性杜松圆锥碳（FTCC）是通过热化学方法合成的。它通过碳化（250°C）和活化（320°C）进行，然后在 0.5 M HAN（HNO 和 HCl 的混合物）中进行表面功能化，并在 90°C 下在 HSO（95%）中加热。该材料用于在单一组分体系（SCS）和二元组分体系（BCS）中吸附亚甲基蓝（MB）与 Cu。在 100mg/L 吸附剂溶液的 pH 值为 10 时，MB 的最大吸附容量为 83.4mg/g。FTCC 对 MB 和 Cu 的吸附均符合准二级动力学模型。自发和吸热的 MB 吸附伴随着负的吉布斯自由能变化（-6.34、-9.20 和-13.78kJ/mol）和正的焓变（133.91kJ/mol）。在低浓度下，BCS 中 Cu 的吸附增加了 14mg/g，而 MB 的吸附减少最少（<4mg/g）。等温线模型（朗缪尔、弗雷德里希、坦金和杜比宁-拉德舒克维奇）支持 BCS 中 Cu 吸附的增加。MB 的吸附热从 SCS（165.16kJ/mol）转移到 BCS（Temkin）的 150.85kJ/mol 和 BCS（D-R）的 57.74kJ/mol，表明由于吸附能的降低，BCS 中 MB 的吸附量减少。BCS 中 Cu 的吸附热（148.43kJ/mol）高于 SCS（155.36kJ/mol），这使得增加的结合能得到了更均匀的分配；因此，FTCC 表面位点增加了 BCS 中 Cu 的吸附量。解吸研究得出，FTCC 对 MB 和 Cu 吸附的解吸率分别为 75%和 79%。本研究建议通过线性和非线性回归拟合来确定等温线和动力学模型对吸附数据的最佳拟合。
