Repository logo
 

Faculty of Engineering and Built Environment

Permanent URI for this communityhttp://ir-dev.dut.ac.za/handle/10321/9

Browse

Subject: search.filters.subject.Membranes

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Prospects of synthesized magnetic TiO2-based membranes for wastewater treatment : a review
    (MDPI AG, 2021-06) Tetteh, E. Kweinor; Rathilal, S.; Asante-Sackey, D.; Chollom, Martha Noro
    Global accessibility to clean water has stressed the need to develop advanced technologies for the removal of toxic organic and inorganic pollutants and pathogens from wastewater to meet stringent discharge water quality limits. Conventionally, the high separation efficiencies, relative low costs, small footprint, and ease of operation associated with integrated photocatalytic-membrane (IPM) technologies are gaining an all-inclusive attention. Conversely, photocatalysis and membrane technologies face some degree of setbacks, which limit their worldwide application in wastewater settings for the treatment of emerging contaminants. Therefore, this review elucidated titanium dioxide (TiO2), based on its unique properties (low cost, non-toxicity, biocompatibility, and high chemical stability), to have great potential in engineering photocatalytic-based membranes for reclamation of wastewater for re-use. The environmental pathway of TiO2 nanoparticles, membranes and configuration types, modification process, characteristics, and applications of IPMs in water settings are discussed. Future research and prospects of magnetized TiO2-based membrane technology is highlighted as a viable water purification technology to mitigate fouling in the membrane process and photocatalyst recoverability. In addition, exploring life cycle assessment research would also aid in utilizing the concept and pressing for large-scale application of this technology.
  • Thumbnail Image
    Item
    Development of a small scale water treatment system for fluoride removal for rural areas
    (2015) Dlamini, Thulani; Rathilal, Sudesh; Pillay, Visvanathan Lingamurti
    Several areas in the world such as the United States of America, Sri Lanka, China, Argentina, Canada, Tanzania, Kenya, South Africa and many others have a problem of high fluoride content in drinking water. Generally fluoride levels above 1.5 ppm in water may result in dental and skeletal fluorosis in humans depending on quantity consumed (Fan et al., 2003; Meenakshi, 2004). Remote rural areas where there are no water treatment facilities are more vulnerable to this problem. Adsorbents such as activated alumina and FR-10 resin seem to have a potential for successful application in rural areas. These methods however require pre-treatment if the feed has high turbidity. A membrane based system called woven fabric microfiltration gravity filter (WFMFGF) developed by Durban University of Technology proved to be suitable for turbidity removal. The main objective of this research was to develop a small water treatment system for fluoride removal. The small water treatment system developed in this study consists of WFMFGF for pre-treatment and an adsorption column. The WFMFGF is made up of a 40 L container packed with 15 immersed flat sheet membrane elements. The operation of the WFMFGF is in batch mode, driven by varying static head. The static head variation results in flow rate variation through the system. This in turn result in variation of contact time, velocity as well as pressure drop in the fluoride removal unit. Specific objectives of the study were: (1) to establish the maximum and minimum flow rates through the WFMFGF system, the total run time before cleaning is required and the best cleaning method for this particular membrane system. (2) to evaluate and compare the performance of activated alumina and FR-10 resin on varying contact time, velocity and pressure drop on the fluoride removal unit. The adsorbents were also compared on adsorption capacity, cost and ease of operation. The minimum and maximum flow rates through the WFMFGF were found to be 5 l/hr and 100 l/hr respectively. It was found that the system can be run for more than a month before requiring cleaning. The suitable cleaning method was found to be soaking the membranes in 0.0225 percent sodium hypochlorite solution overnight and brushing them using a plastic brush. The comparison of the performance of FR-10 resin to activated alumina found that the adsorbents gave equal performance based on the given criteria. FR-10 resin had higher adsorption capacity, gave good quality treated water even with shorter contact time and operated at wider velocity range. Activated alumina on the other hand had an advantage of lower costs, lower pressure drop and ease of use. According to Pontius (1990), the performance of activated alumina can be improved by intermittent operation. Point of use (POU) systems are generally operated intermittently. This improves the fluoride removal efficiency of activated alumina giving it more advantage over FR-10 resin. Based on this activated alumina was selected as the best adsorbent for the system. After the adsorbent was selected, the adsorption column was designed. The column operation regime was 3.5 minutes minimum contact time and 1.17 to 7.8 m/hr velocity range. The activated alumina adsorption capacity was 1.53mg/g. The column had an inside diameter of 70 mm. It was packed with activated alumina to a bed height of 400 mm. The column inlet and outlet pipes were made of PVC with a standard pipe size of 20 mm outside diameter. A valve at the column inlet pipe allowed water to flow through the system.
  • Thumbnail Image
    Item
    Development and evaluation of woven fabric microfiltration membranes impregnated with silver nanoparticles for potable water treatment
    (Elsevier, 2014-02-06) Mecha, C.A.; Pillay, Visvanathan Lingamurti
    Access to clean and safe drinking water is a fundamental human need, which is commonly lacking in remote rural areas. A simple gravity-fed water treatment unit was developed based on woven fabric microfiltration (WFMF) membranes. However, since these membranes are loose micro-filters, the unit has to be used in conjunction with a disinfectant. This paper explores combining the WFMF membranes with silver nanoparticles (AgNPs) using a modified chemical reduction method. The originally white membranes turned brown–yellow due to the surface plasmon resonance of silver; however, there was no significant difference in the morphology of the membranes after the impregnation with 0.0117 wt%AgNPs. The coated membranes were more hydrophilic and had higher water permeability (po0.05). Filtration of turbid water (40–700 NTU) showed that both membranes produced clear permeate (o1 NTU). Treatment of water spiked with bacteria (2500–77,000 CFU/100 mL Escherichia coli) showed that the removal efficiency of uncoated membranes was 84–91% and that of coated membranes was 100%. Accordingly, the coated membranes depicted great potential for water treatment. To the best of our knowledge, this is the first study that investigated the incorporation of AgNPs in WFMF membranes and characterized their properties.