Nik Rashida Nik Abdul Ghani; Siti Syakirah Sulaiman; Amina Tahreen; Mohammed Saedi Jami
Abstract
Arsenic contamination poses a major public health concern and harms the environment with its toxicity. Long term exposure to a high concentration of arsenic is harmful to human health as well as the environmental biodiversity. This study is aimed to fabricate and investigate the possibility of polyethersulfone-graphene ...
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Arsenic contamination poses a major public health concern and harms the environment with its toxicity. Long term exposure to a high concentration of arsenic is harmful to human health as well as the environmental biodiversity. This study is aimed to fabricate and investigate the possibility of polyethersulfone-graphene oxide-polyvinyl pyrrolidone (PES-GO-PVP) nanocomposite adsorptive membrane and use it to enhance the removal of arsenic from wastewater. The nanocomposite membrane in this study was fabricated via the non-solvent induced phase separation (NIPS) method with the addition of polyvinylpyrrolidone (PVP) as a pore-forming agent. Based on the characterization results of GO through Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy, the existence of high quantity of oxygen based functional groups with high degree of oxidation was observed, which indicated that the GO were well-synthesized. The characterization of the membrane indicated that the addition of GO and PVP could impact the membrane hydrophilicity and mechanical stability. Three adsorption parameters (initial concentration of arsenic, pH and contact time) were then optimized using a face-centred central composite design (FCCCD). The arsenic removal efficiency of 88.6 % was obtained with 55 mg/L of initial arsenic concentration, at pH 8 and 75 minutes of contact time between PES-GO-PVP membrane and the arsenic ion. The Langmuir isotherm model fitted the equilibrium data, describing the monolayer adsorption mechanism occurred on the surface of the membrane. Therefore, the results obtained in this study prove the suitability and promising potential of the nanocomposite membrane for effective removal of arsenic through adsorption.
Masoud Samandari; Afshin Tagva Manesh; Seyed Ali Hosseini; Sakineh Mansouri
Abstract
The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed ...
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The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed to the mixed oxide. The SEM images approved Mg-Al LDH comprised of flakes and the calcined LDH comprised of spherical nanoparticles. BET results indicated the specific surface area of 100.2 and 86.3 m2.g-1 for pure LDH and calcined LDH, respectively. The process was optimized by one factor at a time method and considering four process factors i.e. reaction temperature, peroxide dosage, initial phenol concentration, and reaction time. The optimum conditions resulted at initial phenol concentration of 100 ppm, reaction temperature of 60 ºC, with peroxide volume of 3 mL and time on stream of 45 min over calcined LDH with maximum 85% removal of phenol. On the pure LDH, the maximum phenol removal (79%) resulted at peroxide volume of 2.5 mL at 55 min. The study concluded that the calcined Mg-Al LDH due to synergistic effect of MgO and Mg-Al mixed oxide showed higher catalytic activity despite a relatively low surface area.
Mahzad Mirzaei; Reza Khanbabaie; Mohsen Jahanshahi; Ghasem Najafpour Darzi
Abstract
Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated ...
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Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated the literature. Response surface methodology (RSM) in combination with D-optimal design was applied to optimize the synthesis and evaluate the PL intensity as the response which described by a reduced quadratic equation. The relationship between the PL intensity and independent variables (ligand/precursor, reaction time, reaction temperature, pH, and precursors ratio) was investigated using reduced quadratic polynomial equations. The produced QDs in the optimum condition were analyzed by UV-Vis, FE-SEM, and FTIR. The results showed that the nanoparticles have a high PL intensity and a red shift in both emission and absorbtion spectra which is a splendid point for their applications specially in bioimaging. The interaction between variables was not significant and the temperature was the most effective variable of PL intensity. A good agreement between predicted model and experimental data confirmed the correlated model.