Preparation/synthesis of electrospun polymer/metal oxide nanocomposite fibers and their application in treatment of brines

Abstract : Many developing countries around the world still lack access to clean fresh water. This refers to water that is free from contaminants as it is highly essential for human livelihood and environment. In countries along the coast, ocean water is the most available water resource; however, it comes at a salt concentration that is very high for human consumption. Most of available water has a salinity of up to 10 000 ppm and seawater consists of dissolved salt concentrations of about 35 000-45 000 ppm. This lead to desalination process being used as an option to treat seawater and this has become one of the most important processes of providing fresh water in developing countries. Therefore, the aim of this study was to investigate the practicability of using nanometer metal oxides and polymer/NMO composite as the potential adsorbents for adsorption desalination of seawater. The quantification of analytes in sample solutions was done using the inductively-coupled plasma atomic emission spectroscopy (ICP-OES). Nanometal oxide composites such as Fe2O3-SiO2, SiO2/Nb2O5/Fe2O3, Fe2O3-SiO2-PAN and zeolite/Fe3O4 adsorbents were used for the adsorptive desalination of saline water. Fe2O3-SiO2, SiO2/Nb2O5/Fe2O3 and zeolite/Fe3O4 adsorbents were prepared using a sol gel method whereas Fe2O3-SiO2-PAN nanocomposite was obtained using in-situ preparation method. The adsorbents were characterized using different techniques such as scanning electron microscopy (SEM), x-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET). SEM image of Fe2O3-SiO2 nano composite showed the porous morphological structure. The Fe2O3-SiO2 showed partial crystalline pattern due to silica oxide that has pure amorphous structure, whereas the SiO2/Nb2O5/Fe2O3 has an amorphous structure. TEM structure of α-Fe2O3 has dominant shapes of spherical and some few cubic and hexagonal shapes, the hexagonal shape were also observed on Fe2O3-SiO2 nanocomposite material. SiO2/Nb2O5/Fe2O3 adsorbent resembled a core-like structure. The TEM result of Fe2O3-SiO2-PAN revealed that the crystalline Fe3O4 nanoparticles were encapsulated with PAN polymer that suggests the core-shell structure. EDX-mapping analysis showed the uniform elemental distribution which suggests the successful preparation of the in-situ method...Ph.D. (Chemistry

Application of Activated Carbon Banana Peel Coated with Al2O3-Chitosan for the Adsorptive Removal of Lead and Cadmium from Wastewater

This study was aimed at evaluating the adsorption capacity of novel banana peel activated carbon (BPAC) modified with Al3O2@chitosan for the removal of cadmium (Cd2+) and lead (Pb2+) from wastewater. Characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transformed infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller analysis confirmed the synthesized BPAC@Al3O2@chitosan composite material. The univariate approach was used to study the influence of different experimental parameters (such as adsorbent mass, sample pH, and contact time) that affects simultaneous removal of Cd2+ and Pb2+ ions. Kinetic results showed that adsorption favored the pseudo-second-order kinetic model, whereas the adsorption of Cd2+ and Pb2+ was best described by the Langmuir model and the adsorption capacity for Cd2+ and Pb2+ was 46.9 mg g−1 and 57.1 mg g−1, respectively, for monolayer adsorption. It was shown the BPAC composite can be re-used until the third cycle of adsorption–desorption (% Re > 80). Based on the obtained results, it can be concluded that the prepared BPAC@Al3O2@chitosan composite material is cost effective, as it is generated from waste banana peels and can be re-used. In addition, the prepared material was able to remove Cd2+ and Pb2+ up to 99.9%

Recent Progress on Acid Mine Drainage Technological Trends in South Africa: Prevention, Treatment, and Resource Recovery

South Africa is the home of major global mining operations, and the acid mine drainage (AMD) contribution has been attributed to abandoned mine sites and huge pyrite-bearing tailings from coal and gold mines. Determining the true economic impact and environmental liability of AMD remains difficult. Researchers have been looking into several treatment technologies over the years as a way to reduce its possible environmental impact. Different methods for active and passive remediation have been developed to treat AMD. The aim of this review was to describe the AMD-impacted environments and critically discuss the properties of AMD and current prediction and preventative methods and technologies available to treat AMD. Furthermore, this study critically analysed case studies in South Africa, gaps in AMD research, and the limitations and prospects offered by AMD. The study outlined future technological interventions aimed at a pattern shift in decreasing sludge volumes and operational costs while effectively improving the treatment of AMD. The various treatment technologies have beneficial results, but they also have related technical problems. To reduce the formation of AMD, it is recommended that more preventive methods be investigated. Moreover, there is a current need for integrated AMD treatment technologies that result in a well-rounded overall approach towards sustainability in AMD treatment. As a result, a sustainable AMD treatment strategy has been made possible due to water reuse and recovery valuable resources such sulphuric acid, rare earth elements, and metals. The cost of AMD treatment can be decreased with the use of recovered water and resources, which is essential for developing a sustainable AMD treatment process. More study is required in the future to improve the effectiveness of the various strategies used, with a focus on reducing the formation of secondary pollutants and recovery of valuable resources

Ultrasound Assisted Adsorptive Removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from Seawater Using Fe₂O₃-SiO₂-PAN Nanocomposite: Equilibrium Kinetics

This work reports the preparation and application of Fe2O3-SiO2-PAN nanocomposite for the removal of Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti3+ from seawater. X-ray diffraction (XRD), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET) characterized the synthesized composite. The following experimental parameters (Extraction time, adsorbent mass and pH) affecting the removal of major and trace metals were optimized using response surface methodology (RSM). The applicability of the RSM model was verified by performing the confirmation experiment using the optimal condition and the removal efficiency ranged from 90% to 97%, implying that the model was valid. The adsorption kinetic data was described by the pseudo-second order model. The applicability of the materials was tested on real seawater samples (initial concentration ranging from 0.270−203 µg L−1) and the results showed satisfactory percentage efficiency removal that range from 98% to 99.9%. The maximum adsorption capacities were found to be 4.36, 7.20, 2.23, 6.60, 5.06, 2.60, 6.79, 6.65 and 3.00 mg g−1, for Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti4+, respectively