Synthesis And Modification Of Activated Carbon With The Waste Residue Of Chinese Prickly Ash Seeds And Its Adsorption Properties

Chinese prickly ash seeds which are the waste of Chinese prickly ash, have a very rich yield and mainly using to extract Chinese prickly ash seeds oil. The residue of Chinese prickly ash seeds?RPS?, the residual in the production of Chinese prickly ash seeds oil, is mainly consisted of protein, crude fiber, wax, etc. Its utilization is very low, excepting for the muck and fuel. So, the utilization of the waste residue of Chinese prickly ash seeds has become an urgent subject. Therefore, this study was conducted to prepare and modify activated carbon?RAC? with the waste residue of Chinese prickly ash seeds. It was used as adsorbent for removing p-nitrophenol, Acid Orange II and heavy metal ions from aqueous solution. The dessertation was contented of the following parts.1. Activated carbons were prepared with waste residue of Chinese prickly ash seeds?RPS? activated by ZnCl₂ in N₂ atmosphere. It was characterized by the methods of FT-IR, BET, XRD, SEM and TG. Under the conditions that ZnCl₂ concentration is of 50%?mass ratio?, weight ratio of ZnCl₂ to RPS is 1.5,carbonization time is 60 min and carbonization temperature is at 700 ?, activated carbons prepared have highly cracked porous surfaces, grooves and macroporous. The BET surface area, total pore volume and pore volume are 883m2×g-1, 0.6 cm3×g-1 and2.5 nm, respectively. It was used as adsorbent for removing p-nitrophenol from aqueous solution. The adsorption capacity could be achieved to 334 mg × g-1 at adsorbent dose of 0.5 g×L-1, adsorption temperature at 293 K, solution pH of 8.0 and reaction time of 6 h. Thermodynamic study shows the adsorption process can be favorably described by the Sips isotherm. Thermodynamic function calculated shows that the adsorption is spontaneous and endothermic process. The adsorption kinetics is satisfactory fitted by the pseudo-second-order model.2. The adsorption properties of two heavy metal ions(Pb²⁺/Ni²⁺) and Acid Orange II?AO? onto RAC was investigated at temperature of 30? and pH of 5.0. In the mono-component system, the adsorption capacities are 188.4 mg×g-1 for AO, 15.1mg × g-1 for Pb²⁺ and 10.7 mg × g-1 for Ni²⁺. In the binary-component system, theadsorption capacities are 332.68 mg × g-1 for AO and 79.40 mg × g-1 for Pb²⁺ in the AO-Pb²⁺ system and 375.6 mg×g-1 for AO and 38.3 mg×g-1 for Ni²⁺ in the AO-Ni²⁺system. In the ternary-component system, it is 82.7 mg×g-1, 48.8 mg×g-1 and 445.33mg×g-1 for Pb²⁺, Ni²⁺ and AO, respectively. The results show that RAC exhibits an synergic effect on heavy metal ions and AO. The adsorption process can be favorably described by the non-modified Sips isotherm. The adsorption kinetics is satisfactory fitted to the pseudo-second-order model. SEM/EDX and XPS were used to characterize the possible mechanisms of synergic adsorption process.3. The mesoporous silica coated activated carbon?RAC@mSiO₂? produced from RAC was successfully synthesized. It was characterized by the methods of FT-IR,BET, XRD, SEM/EDX and TEM. The BET surface area, total pore volume and pore volume are 69 m2×g-1, 0.6 cm3×g-1 and 32 nm, respectively. The adsorption property of Pb?II? by RAC@mSiO₂ was investigated. The maximum adsorption capacity can be achieved to 74.7 mg × g-1 under the temperature of 303 K, pH of 5.0 and initial concentration of Pb?II? of 100 mg×L-1. Thermodynamics studies show the adsorption process can be favorably described by the Sips isotherm which the adsorption is a spontaneous and endothermic process. The adsorption kinetics is satisfactory fitted to the pseudo-second-order model.