Chitosan/silica composite membrane: adsorption of lead(II) Ion from aqueous solution

Chitosan membrane has the potential to separate lead(II) ions from aqueous solution. However, the kind of membrane has a drawback due to the low structural properties. Thus, this study investigates the role of silica in improving chitosan-based flat sheet membrane for removal of lead(II) ions from aqueous solution. The functional groups and structural morphologies were characterized using Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) spectrometer and Scanning Electron Microscope (SEM), respectively. The membrane performance in terms of adsorption study was conducted at different pHs and initial concentration of lead(II) solution. The FTIR-ATR spectrum showed the existence of new absorption peak of chitosan/silica membrane. SEM images revealted the presence of microvoids on the cross-section of the chitosan/silica membrane whereas pure chitosan membrane possessed dense structure. The adsorption study showed that the composite membrane exhibited higher efficiency of lead(II) removal at optimum pH of 7.0 which was 89.27% as compared to 11.50% of pure chitosan membrane. The amount of lead(II) adsorbed onto the membrane was 57.60 mg/g. Therefore, it indicates the potential use of silica to improve the properties of chitosan membrane for removal of heavy metal from water solution

REVIEW ON THE BIODEGRADABLE RESIN BONDED SAND CASTING

Resin bonded sand casting is widely used for manufacturing automotive parts especially those made of Aluminium Alloys. In general, resin bonded sand casting use alkaline resin as binding agent. Typically, they are from non-biodegradable materials that have issues on reclamation and disposal of the sand as well as cause hazard to the environment.  Therefore, this became a motivation to propose a biodegradable resin as the binding for the resin bonded sand casting mould. Review of this study is reported in this article. From the review, biocure starch resin with water or methyl ester made from plants was selected as binder. Feasibility to make resin bonded sand mould out of this resin need to be established. Further, the sand and cast material should be characterized and analysed for their microstructural and mechanical properties. Indeed, the review has given insight to the gap of this field of knowledge and aid in the development of aim and objectives of the research

STUDY ON OPTICAL PROPERTIES OF GRAPHENE-TIO2 NANOCOMPOSITE AS PHOTOANODES LAYER IN DYE SENSITIZED SOLAR CELL (DSSC)

Dye Sensitized Solar Cell (DSSC) using titanium dioxide (TiO2) has begun to play a significant role in future solar energy since it is known as cost effective and highly efficient. DSSC is the third generation of photovoltaic cells that have been widely investigated as a promising replacement of current commercial solar cell. However, the highest efficiency of DSSC still has not achieved the minimum requirement so that it can be commercialize. Much research has been done to improve DSSC performance by focusing on photoanodes layer. In this study, graphene was employed into TiO2photoanode to increase the efficiency and to enhance the performance of dye sensitized solar cell. Four different samples of nanocomposites paste were prepared by varying the graphene composition of 0.00, 0.30, 0.50 and 0.70 wt%. The prepared samples were coated on Fluorine-Doped Tin Oxide (FTO) conductive glass substrates by a doctor blade method and annealed at 450oC for 30 minutes. The morphology and structure of the graphene-TiO2 nanocomposites layer were characterized by using Field Emission Scanning Electron Microscope (FESEM). The optical properties were studied by using UV-visible spectroscopy. Based on the result show that addition of graphene into TiO2 have provide larger surface area compared to pure TiO2. The optical properties of Graphene-TiO2 nanocomposites also improved as the fundamental of absorption edge has shifted toward longer wavelength and reduce the optical band gap

The effect of mdea/amp and span-80 in water-in-oil (w/o) emulsion for carbon dioxide absorption

Emulsion liquid membrane (ELM) has been widely studied as an alternative method for amine absorption technology in the removal of acid gases such as carbon dioxide (CO2) and hydrogen sulphide (H2S). However, searching for stable ELM formulation with an enhanced CO2absorption remains as challenge. Therefore, in this study, the aqueous solution containing a mixture of methyl diethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) in sodium hydroxide (NaOH) solution was introduced as a dispersed phase, kerosene as continuous phase and Span-80 acts as a surfactant for the formation of water-in-oil (W/O) emulsion. In this study, the dispersed phase consists of 8% v/v MDEA and 4% v/v AMP and the continuous phase which contains 6% v/v Span-80 produced a stable emulsion and exhibited 65.2% of CO2removal. This study indicates that the introduction of blended amine able to produce stable emulsion with an enhanced CO2remova

Influence of the natural zeolite particle size toward the ammonia adsorption activity in ceramic hollow fiber membrane

Natural zeolite is widely used in removing ammonia via adsorption process because of its superior ion-exchange properties. Ceramic particle size affects the adsorptivity of particles toward ammonia. In this study, hollow fiber ceramic membrane (HFCM) was fabricated from natural zeolite via phase inversion. The effect of natural zeolite particle size toward the properties and performance of HFCM was evaluated. The results show that the HFCM with smaller particle sizes exhibited a more compact morphological structure with better mechanical strength. The adsorption performance of HFCM was significantly improved with smaller particle sizes because of longer residence time, as proven by the lower water permeability. A high adsorption performance of 96.67% was achieved for HFCM with the smallest particle size (36 µm). These findings provide a new perspective on the promising properties of the natural zeolite-derived HFCM for ammonia removal

Zeolite-a deposited on glass hollow fiber for forward osmosis applications

This work investigated the effects of reactant concentrations and synthesis periods on in situ deposition of zeolite membranes on glass hollow fibers. The separation performances of the zeolite membranes in forward osmosis applications were studied based on pure water fluxes and reverse solutes. The reactant concentration of 0.66 M enabled zeolite membrane deposited onto glass hollow fiber to give a water flux of 4.50 L m−2 hr−1 with reverse solute of 0.05 kg m−2 hr−1. When the deposition time was reduced to 12 h and 18 h, water fluxes increased to 62.25 and 71.92 L m−2 hr−1, respectively

Enhanced performance of lanthanum orthoferrite/chitosan nanocomposites for the adsorptive photocatalytic removal of reactive black 5

New lanthanum orthoferrite (LaFeO3)/chitosan nanocomposites were synthesized with different chitosan loadings (15 and 35%). Their adsorptive photocatalytic activity in the removal of Reactive Black 5 (RB5) was studied by manipulating the pH of the RB5 solution (pH 3, pH 6, pH 9), the catalyst loading (1 g L−1, 2 g L−1, and 3 g L−1), and the initial concentration of RB5 (30 mg L−1, 50 mg L−1, and 70 mg L−1) under 100 W LED light. The nanocomposites have a nanocrystalline structure similar to LaFeO3 with a lower SBET and PV but a higher PR. The LaFeO3 was distributed well on chitosan matrices with variations in the elemental composition. The band gap was gradually decreased with increased chitosan loading. The nanocomposite with 15% chitosan loading (LC15) resulted as the most prominent photocatalyst with the highest removal of RB5 up to 98.5% under experimental conditions of pH 6, 2g L−1 of catalyst loading, and 30 mg L−1 of initial RB5 concentration. The LC15 showed good stability, wherein the degradation efficiency was more than 90% after the fifth cycle with no significant change in the chemical properties. This work provides a technique to improve the removal of recalcitrant dyes through the processing of adsorptive photocatalysis utilizing adsorbent and perovskite

Enhanced gas separation performance using carbon membranes containing nanocrystalline cellulose and BTDA-TDI/MDI polyimide

This paper presents the derivation of carbon membranes from BTDA-TDI/MDI polyimide (PI) prepared via a dip-coating technique on an inorganic tubular support surface, followed by a heat treatment (stabilization and carbonization) under N2 gas flow. In order to enhance the gas separation performance of the resultant carbon membrane, a synthesized nanocrystalline cellulose (NCC) using tissue paper as an additive was added into the dope solution at various carbonization temperatures of 600, 700, 800, and 900 °C. The NCC was prepared by extracting the unprinted area of a newspaper and was processed as an additive in the polymer solution. The chemical structure, morphological structure, and gas permeation properties of the resultant membrane were analyzed. Special attention was given to the physicochemical characteristics of the resulting PI/NCC-based carbon membrane and its corresponding gas permeation properties. Pure gas permeation tests were performed using CO2, CH4, O2, and N2 at room temperature. The gas permeation data demonstrated that the carbon membrane exhibited an excellent performance compared to the polymeric membrane. Enhancement in both gas permeance and selectivity were observed in the NCC-containing carbon membranes prepared at carbonization temperature of 800 °C, with the CO2/CH4 selectivity of 68.2 ± 3.3, the CO2/N2 selectivity of 66.3 ± 2.2, and the O2/N2 selectivity of 9.3 ± 2.5, with respect to the neat carbon membrane. By manipulating various carbonization temperatures, carbon membranes with different structures and properties were obtained