Muneer M. Ba-Abbad

Visible light photocatalytic activity of Fe3+-doped ZnO nanoparticle prepared via sol–gel technique

The optical properties of a ZnO photocatalyst were enhanced with various dopant concentrations of Fe(3+). Doped ZnO nanoparticles were synthesized via a sol-gel method without the use of capping agents or surfactants and was then characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The results showed that ZnO has a wurtzite, hexagonal structure and that the Fe(3+) ions were well incorporated into the ZnO crystal lattice. As the Fe(3+) concentration increased from 0.25 wt.% to 1 wt.%, the crystal size decreased in comparison with the undoped ZnO. The spectral absorption shifts of the visible light region (red shift) and the band gap decreases for each Fe-ZnO sample were investigated. The photocatalytic activities of the ZnO and Fe-ZnO samples were evaluated based on the degradation of 2-chlorophenol in aqueous solution under solar radiation. The samples with a small concentration of Fe(3+) ions showed enhanced photocatalytic activity with an optimal maximum performance at 0.5 wt.%. The results indicated that toxicity removal of 2-chlorophenol at same line of degradation efficiency. Small crystallite size and low band gap were attributed to high activities of Fe-ZnO samples under various concentrations of Fe(3+) ions compared to undoped ZnO.

Toxicity evaluation for low concentration of chlorophenols under solar radiation using zinc oxide (ZnO) nanoparticles

Photo catalytic degradation of chlorophenols in aqueous solution by ZnO nanoparticles under sunlight was investigated. The toxicity of chlorophenols was evaluated by agar plates technique with paper discs in the presence of Escherichia coli. The relative toxicity data of chlorophenols, before and after degradation, was used in comparing between them. The degree of toxicity was estimated by clear zone around each paper disc of chlorophenols. Results show toxicity of chlorophenols as PCP>TeCP>2,4,6TCP>2,4-DCP>2-CP before photocatalytic degradation. After degradation, no more toxicity was observed by clear zone around each paper disc. The toxicity test indicates that higher degradation of chlorophenols occurred by ZnO nanoparticles under sunlight as alternative method for treatment.

Size and shape controlled of α-Fe2O3 nanoparticles prepared via sol–gel technique and their photocatalytic activity

Haematite (α-Fe2O3) nanoparticles (NPs) of different sizes and morphologies were prepared from two different iron precursors (iron acetate (A) and iron nitrate (N)) using the sol–gel technique, through a reaction with oxalic acid. A pure α-Fe2O3 phase (rhombohedral) that contained particles of different sizes and shapes were obtained from both iron precursors. Transmission electron microscope measurements showed average sizes of 23 ± 2 and 30 ± 2 nm for α-Fe2O3 (A) and α-Fe2O3 (N) formed NPs, respectively. The observed uniform spherical shape for the α-Fe2O3 (A) formed NPs is due to the presence of carboxylic acid (acetic acid) used to control the nucleation and growth process of α-Fe2O3 NPs. However, quasi-spherical particle shapes for α-Fe2O3 (N) were produced in the presence of a mineral acid (nitric acid), which caused the particles to be constrained during their growth step. However, the optical analysis showed that the band gaps of α-Fe2O3 (A) and α-Fe2O3 (N) as 2.63 and 2.60 eV were found, respectively. The surface area results exhibited that both α-Fe2O3 NPs were a porous material with a higher area for α-Fe2O3 (A), which resulted from the uniform shape and smaller size of particles. The magnetic properties were observed to be slightly different for both α-Fe2O3 NPs, which were also attributed to the different particle size of the NPs. Higher photocatalytic activity for congo red dye and 4-chlorophenol degradation under sunlight was achieved by α-Fe2O3 (A), which was attributed to the smaller size and higher surface area compared to α-Fe2O3 (N) NPs.Graphical Abstract

Solar Photocatalytic Degradation of 2,4-Dichlorophenol by TiO2 Nanoparticle Prepared by Sol-Gel Method

The solar photocatalytic degradation of 2,4-dicholrophenol in aqueous solution was carried out direct solar radiation without any collector. A slurry reactor with TiO2 nanoparticles catalyst was used. The catalyst sample was prepared by sol-gel method from titanium tetra-isopropoxide as raw material and calcinated at 400°C. The photocatalytic activity of TiO2 nanoparticles were evaluated by photocatalytic degradation of initial concentration (50 mgl-1) 2,4-dicholrophenol under solar irradiation. The average solar intensity of ultra violet (UV) was recorded as 23 Wm-2. HPLC was used for monitoring the concentration of 2,4-dicholrophenol in solution at different time intervals during the experiment. The degradation efficiency of 2,4-dicholrophenol removal was 93.8% at pH solution of 6, irradiated for 1 h and using optimum amount of catalyst 2gl-1 .

Evaluation of the operating parameters for the separation of xylitol from a mixed sugar solution by using a polyethersulfone nanofiltration membrane

Nanofiltration (NF) membranes may offer a good route for the recovery of xylitol due to the difference in the size of its particles compared to the other sugars. We evaluated the ability of an in-house polyethersulfone (PES) NF membrane to separate xylitol from a simulated broth solution containing xylose and arabinose. Initially, a Box-Behnken design was utilized to optimize the factors that were significantly involved in the recovery of xylitol, such as the concentration of the components, the composition of the solution, and the pressure. The results obtained from the analysis of the experimental response revealed that the fabricated PES membrane was able to retain 92% of the xylitol and remove 50% of the arabinose, with the purity of the xylitol being enhanced accordingly. The results of fouling showed a good membrane performance for long-term filtration. The concentration polarization was dominated by the membrane pores and the charge. It could be concluded that nanofiltration has a high potential to recover xylitol from its corresponding sugars.

Synthesis of Iron Oxide Nanoparticles to Enhance Polysulfone Ultrafiltration Membrane Performance for Salt Rejection

Synthesis of Iron Oxide Nanoparticles to Enhance Polysulfone Ultrafiltration Membrane performance for Salt Rejection Muneer M. Ba-Abbad*, Abdul Wahab Mohammad, Mohd S. Takriff, Rosiah Rohani, Ebrahim Mahmoudi, Khalefa A. Faneer, Abdelbaki Benamo Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. Gas Processing Centre, Qatar University, P. O. Box 2713 Doha, Qatar. Department of Chemical Engineering, Faculty of Engineering and Petroleum, Hadhramout University of Science &Technology, Mukalla, Hadhramout, Yemen. muneer711@gmail.com

Synthesis and characterization of Sm3+-doped ZnO nanoparticles via a sol–gel method and their photocatalytic application

Spherical ZnO nanoparticles doped by samarium ions were successfully synthesized via a simple sol–gel method. The structures, morphologies, optical properties and surface areas were investigated for all samples using specific characterization methods. The hexagonal wurtzite structure of ZnO and samarium-doped ZnO nanoparticles were determined. The results obtained showed that the sizes of samarium-doped ZnO nanoparticles decreased with increasing samarium ion concentration. It was noticed that in the presence of samarium ions, the band gap slightly changed from the 3.198 eV of ZnO to 3.288 eV for samarium-doped ZnO with enhanced absorption in the UV region. This can be attributed to the transition of electrons from the conduction band to the acceptor energy level of samarium. The XPS results of samarium-doped ZnO, showed that only one oxidation state of samarium, with good incorporation into the ZnO matrix, was presented, with no peak of samarium oxide. The surface areas analyses showed that higher surface areas were obtained for samarium-doped ZnO, which is attributed to the smaller size of the particles. The photocatalytic degradation of 2-chlorophenol was investigated under sunlight in presence of ZnO and samarium-doped ZnO nanoparticles. A higher performance of samarium-doped ZnO for photocatalytic degradation of 2-chlorophenol at 0.50 wt.% was observed, compared to pure ZnO nanoparticles under the same experimental conditions.Graphical abstract

Artificial Neural Network (ANN) for Optimization of Palm Oil Mill Effluent (POME) Treatment using Reverse Osmosis Membrane

The treatment of palm oil mill effluent (POME) by Reverse Osmosis (RO) membrane was achieved experimentally. The biological oxygen demand (BOD), chemical oxygen demand (COD) and Color as final response of POME treatment process were selected. However, main influence factors on POME treatment process as concentration, transmembrane pressure and pH were tested on responses. The experimental results of responses were compared to the prediction by applying of Artificial Neural Network (ANN) as a simulation technique to create model of the process. Higher validation of ANN model was found for COD, BOD and Color which the prediction values very close compared to experimental result. The COD removal was investigated as a major affect factor in experiments. The best removal of COD was obtained at lower of POME concentration, pH, transmembrane pressure and time of contact. Therefore, these results showed that appreciate model created by ANN for POME treatment process which contributed easily to apply in industrial filed as future application.