Photocatalytic of Thiophene Desulfurization

Thiophene, found in the fuels is a heterocyclic five-membered ring consisting of sulfur as the heteroatom, with two pairs of electrons at the S atom along with a pair in the six-electron π-system and the others in the ring. Thiophene give negative impacts on living things and also the atmosphere. The presence of sulfur in fuels will lead to the emission of sulfur dioxide into the atmosphere and lead to atmospheric pollution such as acid rain. Thiophene is difficult to remove by using conventional desulfurization processes such as hydro-sulfurization (HDS). Thus, the photocatalytic process is the best alternative method available to degrade thiophene. The photocatalytic process only requires a minimal quantity of catalyst and the by product is almost zero or less harmful to the environment and living things. The process efficiency depends strongly on the chosen photocatalyst. ZnO/KCC provides great potential as the photocatalyst. Hence, this review paper focus on photocatalytic thiophene desulfurization using ZnO/KCC as the photocatalyst

Effect of Initial pH for Polluted River Water Treatment Via Pilot Scale Membrane Photocatalytic Reactor (MPR)

Conventional technologies as physical, chemical, and biological treatment have low efficiency, tendency towards fouling, and use high energy consumption respectively. Coagulation-flocculation base treatment, nearly 40-60% while the latest technologies as advanced organic process (AOP) with Fenton-reagents nearly to 80-85% in dissolved organic compound (DOC) reduction respectively. It proves that, the emerges technology and new green technology is needed. Therefore, the objective of this study is; (i) to treat polluted river using pilot-scale MPRs with different initial pH of 5, 7 and 9 and adsorption-desorption time contact for 20, 30 and 40 minutes using 0.05 g/L ZnO-Kaolin loading, 225W light intensity, pressured 1 barg and 30 minutes photocatalytic reaction time. (ii) analysing the physico-chemical quality of the water before and after the treatment as turbidity, ammoniacal nitrogen () biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), and pH levels using HACH method with 90.89%, 84.93%, 83.19%, 99.38%, 19.47% and 0.63% removal efficiency respectively. (iii) analysis the kinetic reaction between pseudo-first and pseudo-second order model by using turbidity data. In conducting the experiment, the sample of polluted river water was taken at Sungai Sembrong, Batu Pahat. From the result obtained, when pH 5 and time adsorption-desorption time contact for 20 minutes was the optimum condition in degrading and removing the organic matter. Moreover, it obeying pseudo-second order model which relates with chemisorption process between the ZnO-Kaolin and organic compounds. Overall, MPRs claimed as a promising technology that environment-friendly for wastewater treatment applications

Decolourization of an azo dye in aqueous solution by ozonation in a semi-batch bubble column reactor

ABSTRACT: The oxidative degradation of the azo dye Reactive Red 120 by ozonation was investigated. The decolourization was carried out by bubbling ozone at the bottom of a bubble column reactor containing the dye solution. The colour, chemical oxygen demand, and total organic carbon removal were evaluated, and the contaminants were characterized based on the changes in UV-Vis and FT-IR spectra. It was observed that changes of UV-Vis spectra represent the disappearance of both azo and aromatic groups, which causes the colour removal. FT-IR analysis indicated that ozonation shifts the functional groups in the azo dye which results in decolourization, a decrease in aromaticity, and an increase in acidity. The results indicate that the chromophore is destroyed and partially mineralized to small fragments during ozonation. The alkaline pH was favourable to decomposition by ozonation, initiated by the formation of the hydroxyl radicals. The oxidation followed first-order kinetics and the completed decolourization confirmed the capability of ozonation to cleave the azo bond from the dye

Polluted River Water Treatment Via Pilot-Scale Membrane Photocatalytic Reactor (MPR) Incorporated Zno-Kaolin Under Different Light Intensity

Polluted river water treatment utilizes a mix of physical, chemical, and biological processes and activities. Conventional systems, including coagulation, flocculation, sedimentation, filtration, and disinfection, have several limitations. Hence, the Membrane Photocatalytic Reactor (MPR) is one of the most promising methods for polluted river water treatment. ZnO-Kaolin nanoparticles served as great photocatalysts for MPR performance. This study focuses on the pilot-scale hybrid MPR treatment of polluted river water under different light intensities (100, 125, and 225 watts) and irradiation times (20, 30, and 40 minutes). The treated water quality analysis is based on the Environmental Quality Act 1974 (EQA 1974). The kinetic rate was also investigated using pseudo-first-order and pseudo-second-order models. It was found that 225 watts and 30 minutes were the optimum values. The pilot scale hybrid MPR proved to fit well with the pseudo-second-order kinetic models, suggesting that the degradation follows a chemisorption mechanism. In conclusion, we believe the hybrid MPR pilot-scale system will enhance efficiency in cleaning dirty river water, all while meeting the standards of the EQA 1974

Polluted River Water Treatment Via Membrane Photocatalytic Reactor (MPR) Incorporated ZnO-Kaolin

Rivers provide essential resources for human use both in agriculture and aquatic ecosystems, which are particularly vulnerable to contamination. The polluted river water was treated using MPR incorporated Zno-Kaolin. The ZnO-Kaolin was synthesized through precipitation method and calcined at 550C. The characterization of the ZnO-kaolin was done using FTIR and XRD. It was found no impurities occurred during the synthesis. The Zno-Kaolin was then incorporated with MPR to investigate the reduction performance under different conditions, i) effect of initial pH, ii) effect of dosing and iii) effect of initial concentration. it was found that the optimal pH for the reduction is at pH 5, and at dosage 0.05 g/L. It was found the 100% concentration gave the highest reduction for all water quality index (salinity,TDS, conductivity). It can be concluded that MPR incorporated Zno-kaolin effectively treat polluted river water

Zeolite-A deposited on glass/yttria stabilized zirconia forward osmosis membrane for desalination application

The global water scarcity is now a major concern, which made recovering fresh water from seawater is the best alternative. Membrane-based technologies have been widely adopted in desalination, performed using reverse osmosis (RO) and forward osmosis (FO). Zeolite membrane showed great potentials for desalination due to the chemical and thermal stabilities. Zeolite membrane is generally developed by depositing zeolite onto a support material. However, there is a great tendency for delamination to occur. Unsupported zeolite membrane was developed as an alternative to overcome the cracking problem, but the unsupported zeolite membrane transforms into a glass membrane during sintering process. The glass membrane produced have a dense structure, which increased the water resistance pathway in the membrane, and resulted in low flux. Hence, in this study yttria-stabilized zirconia (YSZ) particles were added to increase the flux. Zeolite membrane was developed by depositing zeolite onto glass/YSZ hollow fibre, using the hydrothermal method, to improve the performance of the membrane. Thus, this study aims to i) fabricate glass hollow fibre using zeolite as a starting material, ii) investigate the effects of YSZ particles addition on the membrane performances and iii) evaluate zeolite deposition parameters on the glass/YSZ hollow fibre performances. The glass membrane was fabricated using a phase inversion and sintering technique, by a transformation of zeolite to glass during the sintering process. The YSZ was added into the glass hollow fibre through the same method of the aforementioned glass hollow fibre. The zeolite was deposited onto the glass/YSZ hollow fibre through a hydrothermal method, in an autogenous condition at 120 °C for various synthesis time. Zeolite transformed into glass due to the changed in the arrangement of the molecular structure. Zeolite, a crystalline phase changed to glass, an amorphous phase, when exposed to high temperature. The addition of the YSZ particles improved the permeation by reducing the pathway resistance through the void formed during the sintering process but gave low rejection. To improve the rejection, zeolite was deposited onto the membrane at different concentration and synthesized time. It was found that the suitable conditions were at 0.66 M concentration, and synthesis for 18 hours. The zeolite deposited on glass/YSZ membrane was able to perform sodium chloride (NaCl) rejection thus gave 62.25 L m-2 hr-1 and 0.11 kg m-2 hr-1 for solute flux and reverse solute flux, using FO water filtration system. It can be concluded that the zeolite membrane on glass hollow fibre was capable for desalination application with high flux and low reverse solute flux. A further investigation on the zeolite membrane deposited on glass hollow fibre i.e., to control the zeolite layer and a study to reduce the risk of delamination of the zeolite layer should be conducted

The feasibility study of CAU-1 as an adsorbent for Cu, Zn, Pb, As, Fe and endocrine disrupting chemical bisphenol-A (BPA)

This work discusses the feasibility of CAU-1 as an adsorbent for both heavy metals and bisphenol A (BPA). CAU-1 was synthesised solvothermally at 120 °C for 8 h. Batch adsorption study was done to investigate the feasibility of CAU-1 as the adsorbent. The CAU-1 weight was constant throughout the study, 0.01 g. CAU-1 was characterised using zeta potential analysis, SEM, FTIR, TGA, and XRD. CAU-1 was only able to remove BPA and not able to adsorb heavy metals due to the repulsion forces between CAU-1 and the heavy metals. Thus, BPA was used as adsorbate for CAU-1 adsorption study. The optimum conditions for BPA adsorption on CAU-1 were at pH 7 and 3 h contact time. The adsorption capacity increased infinitely with increasing concentration of the BPA. The maximum equilibrium adsorption capacity (qe) of CAU-1 for BPA was 310.1 mg/g at 25 °C, and the adsorption followed the pseudo-second-order kinetic model. The thermodynamic studies indicate that the adsorption reaction is a spontaneous and endothermic process, a favourable reaction

ZIF-8 membrane supported on alumina hollow fiber with enhanced salt removal by forward osmosis

This work describes the development of ZIF-8 membranes supported on alumina hollow fiber via electroless deposition (ELD) of ZnO followed by solvothermal synthesis for water desalination. The relatively low operating temperature of ELD of ZnO provided an alternative method to fabricate pure-phase ZIF-8 membrane. As-prepared ZnO and ZIF-8 samples were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), water contact angle, and Fourier transform infrared spectroscopy (FTIR). The performance of ZIF-8 membrane was evaluated using forward osmosis (FO) using active layer facing feed solution. The well-intergrown membrane provided high water flux up to 12.25 L/m2h with reverse solute flux as low as 0.029 kg/m2h when using 100,000 ppm NaCl solution and water as the draw and feed solutions, respectively. Furthermore, the membrane showed high KCl (87.8%) and NaCl (88%) rejection and excellent CaCl2 (95%) and MgCl2 (98%) salt rejection in FO using 1.0 M dextrose solution as the draw solution. Interestingly, the rejection of AlCl3 salt was only as high as 46% due to the instability of ZIF-8 in the AlCl3 solution causing the loss of its crystallinity. The ZIF-8 material showed no degradation in various saline solutions (e.g., KCl, NaCl, CaCl2, and MgCl2) except for AlCl3 solution even at a high concentration of 40,000 ppm for 720 h. The findings suggest that the prepared ZIF-8 membrane is a potential membrane for desalination application due to its excellent separation performance toward certain salts

Composite zeolite hollow fiber membrane for the removal of nickel using forward osmosis

This work discusses the preparation, characterization, and feasibility test of composite zeolite hollow fiber membranes, with UV-curable resin as a secondary coating material, in removing Ni (II) using FO process. The preparation of the membrane started by depositing zeolite membrane onto alumina hollow fiber, followed by photopolymerization process once the outer layer was fully covered. Various characterization techniques were used on the composite membrane, namely field emission-scanning electron microscopy (FESEM), X-ray diffraction analysis, Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, contact angle measurement, and performance tests using FO. The results show that the membranes enabled a reduction of reverse solute once incorporated with UV-curable resin. The lowest reverse solute flux obtained was 0.008 kg m-2 h-1, when pure water was flowed in the outer surface and 100,000 mg L-1 sodium chloride (NaCl) was used in the lumen. The UV-curable resin was unstable in the presence of Ni (II), which later formed complex ions. Adsorption of Ni (II) ions caused agglomeration of zeolite particles, causing membrane defects