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Kinetics and Effects of Process Parameters on Oil Adsorption using Activated Carbon from Rubber Seed Kernels (Hevea brasiliensis)

2023-01-01 , Aswadi M.A.H. , Hairul Nazirah Abdul Halim , Nasaruddin N.F.N. , Siti Khalijah Mahmad Rozi , Zulfakar Mokhtar , Tan L.S. , Jusoh N.W.C.

Wastewater contaminated with oil discharged from food processing industries need to be treated properly in order to avoid clogging the drainage and sewerage systems. The removal of oil via the adsorption technique using biomass as a low-cost adsorbent was proposed in this study. Rubber seed kernels (RSKs) were used as the raw material to synthesise activated carbon. The RSKs were impregnated with 10 wt% of phosphoric acid (H3PO4) and carbonised at 500 °C to produce rubber seed kernel activated carbon (RSKAC). Different parameters were included in batch adsorption studies, namely, contact time (30 to 240 min), activated carbon dosage (0.5 to 2.5 g), and temperature (25 to 65 °C). The performance of each process parameter was evaluated based on the adsorption capacity of oil onto the synthesised RSKAC. Pseudo-first order and pseudo-second order models were applied to analyse oil adsorption kinetics using RSKAC. Based on the experimental results, the highest oil adsorption was achieved at 150 min of contact time, 2.5 g of RSKAC, and at a temperature of 35 °C. Oil adsorption using RSKAC in this study followed the pseudo-second order kinetics model. These findings revealed that RSKAC could be synthesised as a low-cost adsorbent for oil adsorption.

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Fe₃O₄-Doped polysulfane membrane for enhanced adsorption of copper from aqueos solution

2024-01-01 , Wan Khairunnisa Wan Ramli , Nur Maisyatul Syalina Abdul Wahab , Siti Khalijah Mahmad Rozi , Syumayyah Rasis , Gavin Chew Tiong Chuen , Lew Guo Liang

Water pollution, especially from industrial wastewater has become one of the major global environmental problems. As the result of rapid industrialization, the expansion of industries such as the electroplating industry has resulted in an increase in heavy metals effluent, especially copper, in the wastewater, and this poses detrimental effects on the biodiversity and environment. The abatement of copper pollution has received widespread attention, and continuous research advancement has been observed in adsorption and membrane technology. Nanofiltration membranes with nanopores recorded higher suitability to remove ions but at the expense of membrane fouling as a result of the formation of contaminants on the surface layer that blocks the diffusion of contaminants into the membrane substructure. This research highlights the incorporation of Fe3O4 nanoparticles into the polysulfone (PSf) membrane matrix as an adsorptive membrane and their possible adsorption mechanism towards Cu, which can manifest the combined characteristics of both removal techniques. Fe3O4 nanoparticles were synthesized using the co-precipitation method. Fe3O4-doped PSf membranes were then synthesized with various concentrations of Fe via the Non-solvent Induced Phase Separation (NIPS) technique. The physicochemical properties of the Fe nanoparticles and the membranes were evaluated using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), water contact angle and porosity testing. Crystal phase analysis confirmed the formation of magnetite Fe3O4 in a cubic structure. Agglomerations of Fe NPs on the membrane surface were observed for membranes with lower Fe concentrations, suggesting the possibility of poor blending and this contributed to the lower adsorption capability of these membranes. Membranes with 2 wt.% Fe concentration (Fe-2.0) exhibited the highest Cu(II) ions adsorption capacity of 637 mg/g, which is trifold of those recorded for pristine PSF membrane (Fe-0.0). The adsorption data of Cu adsorption were best fitted into the Temkin isotherm and pseudo-second-order models, suggesting an adsorption mechanism involving an exothermic chemical interaction between Cu ions and the Fe3O4 NPs within the membrane. This research confirms the potential of incorporating Fe3O4 in the PSf membrane backbone to enhance Cu removal as an adsorptive membrane, even at lower NP concentrations.