Allaboun Hussein, Abu Al-Rub Fahmi A
Chemical Engineering Department, Jordan University of Science and Technology, P. O. Box 3030, Irbid 22110, Jordan.
Jordan Atomic Energy Commission, P. O. Box 70, Amman 11934, Jordan.
Materials (Basel). 2016 Mar 30;9(4):251. doi: 10.3390/ma9040251.
Five different activated carbons (ACs) have been prepared from dried date pits using air and phosphoric acid as activating agents. The used phosphoric acid:date pit ratio dictated the characteristics of the prepared ACs; the equivalent BET-nitrogen surface area varied from 794 m²/g for a ratio of 5:1, to 1707 m²/g for a ratio of 2:1, whereas the micropore volume changed in value from 0.24 cm³/g for the 5:1 ratio to 0.59 cm³/g for the 2:1 ratio. The prepared ACs were tested to remove 4-chlorophenol (4-CP) from aqueous solutions by means of batch adsorption process. The prepared 2:1 AC exhibited the highest uptake with a maximum of 525 mg/g. Equilibrium pH studies showed that 4-CP removal was pH dependent; the maximum uptake occurred at an equilibrium pH value of 5.5. Dynamic studies showed that 4-CP uptake on 2:1 AC is rapid, with 80% of the maximum uptake achieved during the first 40 min. Both surface adsorption and intraparticle diffusion were identified to be effective adsorption mechanisms. Kinetic studies indicated a pseudo second-order reaction. Results of equilibrium adsorption experiments showed that the adsorption of the 4-CP on 2:1 AC is best described by the Langmuir model. The thermodynamics parameters of the adsorption (Δ⁰, Δ⁰, and Δ⁰) were determined by studying the adsorption equilibrium at different temperatures. The values of these parameters indicated the spontaneous and endothermic nature of the adsorption phenomenon of 4-CP on the prepared ACs.
使用空气和磷酸作为活化剂，从干枣核制备了五种不同的活性炭（AC）。所用磷酸与枣核的比例决定了所制备活性炭的特性；等效BET氮表面积从比例为5:1时的794 m²/g变化到比例为2:1时的1707 m²/g，而微孔体积值从5:1比例时的0.24 cm³/g变化到2:1比例时的0.59 cm³/g。通过间歇吸附过程测试了所制备的活性炭从水溶液中去除4-氯苯酚（4-CP）的能力。所制备的2:1比例的活性炭表现出最高的吸附量，最大吸附量为525 mg/g。平衡pH研究表明去除4-CP与pH有关；最大吸附量出现在平衡pH值为5.5时。动态研究表明2:1比例的活性炭对4-CP的吸附很快，在前40分钟内达到最大吸附量的80%。表面吸附和颗粒内扩散均被确定为有效的吸附机制。动力学研究表明为拟二级反应。平衡吸附实验结果表明，4-CP在2:1比例的活性炭上的吸附最适合用Langmuir模型描述。通过研究不同温度下的吸附平衡，确定了吸附的热力学参数（Δ⁰、Δ⁰和Δ⁰）。这些参数的值表明4-CP在所制备活性炭上的吸附现象具有自发性和吸热性。
