UWCScholar :: Browsing by Author "Bladergroen, Bernard"

Browsing by Author "Bladergroen, Bernard"

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Development of a bipolar nickel-iron battery prototype for energy storage
(University of Western Cape, 2021) Ltaief, Mohamed Ali Ben; Bladergroen, Bernard
Energy storage systems represent a viable option to integrate renewable energy sources into the grid network. Multiple energy storage technologies are available such as mechanical, electrical, thermal, and electrochemical storage technologies. Battery Energy Storage Systems are considered as an accepted solution for energy storage with advantages such as, sustained power delivery, geographical independence and, fast response capability. This thesis describes the development of rechargeable bipolar Nickel-Iron batteries as potential candidates for cost effective energy storage solutions. The first objective of this work was to design a bipolar electrode comprising an Iron (Fe)-based anode, a Nickel (Ni)-based cathode and a flexible bipolar plate and to optimise its production process in order to attain high performance in terms of capacity and efficiency. Research questions to be answered included;
Development of capacitive deionisation electrodes: optimization of fabrication methods and composition
(University of the Western Cape, 2017) Nkuna, Shonny; Bladergroen, Bernard
The objective of this research was to optimize the fabrication methods for and compositions of electrodes for the Membrane Capacitive Deionisation (MCDI) system. Two electrode fabrication methods were developed, namely a spray coating- and a casting method. The compositions of the electrodes were varied yielding a total of 14 different electrode in an attempt to optimize the fabrication methods and compositions of the electrodes. Three activated carbons were utilized in this study, TOB, YP50F and YP80F, these activated carbons have different surface areas and porosity therefore were affected different by the materials added in the ink. Carbon black and carbon nanotubes were used as conductivity additives to enhance the conductivity of the electrodes. Lastly a polymer binder was added to increase the mechanical integrity of the electrode, this polymer was typically PVDF. For some electrodes, PVDF was replaced with ion exchange polymers in an attempt to provide ion conductive properties to the electrodes. To establish the charge capacity of the electrodes Cyclic Voltammetry was used, BET analysis evaluated the surface area and porosity of the raw materials and fabricated electrodes. Scanning Electron Microscopy was used to verify surface morphology and uniformity. Ion adsorption capacity measurements were performed using a specially designed MCDI cell. The objectives of this study were achieved, the fabrication methods were optimized with the casting method producing superior electrodes. Apart from fulfilling the research objectives, the current research work generated significant scientific value by revealing how the production method impacts the electrode's surface area and electrode adsorption capacity.
Development of capacitive deionisation electrodes: optimization of fabrication methods and composition
(University of the Western Cape, 2020) Smith, Nafeesah; Bladergroen, Bernard
Membrane Capacitive Deionisation (MCDI) is a technology used to desalinate water where a potential is applied to an electrode made of carbonaceous materials resulting in ion adsorption. Processes and materials for the production of electrodes to be applied in Membrane Capacitive Deionisation processes were investigated. The optimal electrode composition and synthesis approached was determined through analysis of the salt removal capacity and the rate at which the electrodes absorb and desorb ions. To determine the conductivity of these electrodes, the four point probe method was used. Contact angle measurements were performed to determine the hydrophilic nature of the electrodes. N2 adsorption was done in order to determine the surface area of carbonaceous materials as well as electrodes fabricated in this study. Scanning electron microscopy was utilised to investigate the morphology. Electrodes were produced with a range of research variables; (i) three different methods; slurry infiltration by calendaring, infiltration ink dropwise and spray-coating, (ii) electrodes with two different active material/binder ratios and a constant conductive additive ratio were produced in order to find the optimum, (iii) two different commercially available activated carbon materials were used in this study (YP50F and YP80F), (iv) two different commercially available electrode substrates were utilised (JNT45 and SGDL), (v) different slurry mixing times were investigated showing the importance of mixing, and (vi) samples were treated at three different temperatures to establish the optimal drying conditions. Through optimization of the various parameters, the maximum adsorption capacity of the electrode was incrementally increased by 36 %, from 16 mg·g-1 at the start of the thesis to 25 mg·g-1 at the end of the study.
Economic analysis of water recovery from flue gas: A South African case study
(University of the Western Cape, 2020) Hansen, Shadeon Doawon; Ocran, Matthew; Bladergroen, Bernard
In order to comply with the Air Quality Act 2010, Eskom will have to install flue gas desulphurisation (FGD) plants for both new and old power stations. Wet-flue gas desulphurisation (wet-FGD) is adopted world-wide as an effective flue gas treatment technology and therefore will be adopted by Eskom. During the process of desulphurisation, the flue gas is stripped of SO2 but gains a substantial amount of water. Sustaining this process requires a continuous supply of fresh water, a scarce resource in many places where power stations are built. This research investigates the economic feasibility of technologies capable of recovering water from flue gas. The following technologies were considered to capture water vapour from flue gas taking Eskom’s Medupi Power Station as a case study; condensing heat exchanger technology, desiccant drying systems and membrane technology using membrane modules developed by other students in this project. The water vapour selective membrane technology turned out to be superior.
Effluent water treatment utilising a combination of hydrodynamic shear and flotation technology for the specific application of wastewater from the oil and gas industry
(University of the Western Cape, 2022) Cerff, Bradley Robert; Bladergroen, Bernard
Water plays an important role in the petrochemical production and refining processes. The wastewaters released by these processes are often rich in petroleum pollutants, that requires significant treatment prior to disposal. Of particular importance is the processing of oil in water (o/w) emulsions. The processing and treatment of oil emulsions is focussed on breaking the emulsion and separation into the aqueous and oil phases for further appropriate disposal. The general approach is to optimise the processing to achieve relatively clean water, that can be recycled or discharged into the environment, whereas the oil is disposed of or recycled appropriately. The use of chemical coagulants and flocculants results in the degradation of the oil phase forming sludges as well as toxicity issues when using aluminium based coagulants.
Production and evaluation of capacitive deionization electrodes earmarked for the removal of ions from winery wastewater
(University of the Western Cape, 2023) Theron, Cleeve; Bladergroen, Bernard
Membrane capacitive deionization (MCDI) is a desalination technology considered to be cost effective specifically for salt bearing solutions with concentrations below 2000 mg‧L-1, which includes general winery wastewater. To consider winery wastewater to irrigate vineyards, the water needs to be desalinated to some extent. This study aims to establish whether in-house developed electrodes could be applied in MCDI to reduce the concentration of ions contained in winery wastewater model solutions. This would allow wineries to recycle wastewater for irrigation purposes and reduce their reliance on fresh water intake, increasing the winery industry’s drought resilience. Electrode optimization was done by systematically varying electrode production parameters and targeting several specific electrode variables which influence the performance of the electrode in terms of, maximum salt adsorption capacity (mSAC), practical salt adsorption capacity (pSAC), average salt adsorption rate (ASAR), wettability, through-plane electrical conductivity and surface area and pore size distribution with diameters in the mesopore size range.
A review of the processes associated with the removal of oil in water pollution
(MPDI, 2021) Cerff, Bradley; Key, David; Bladergroen, Bernard
Water plays an essential role in production and refining processes. Many industries that use petrochemicals also require water, especially for cleaning purposes. The wastewaters released by these processes are often rich in petroleum pollutants, which requires significant treatment prior to disposal. The presence of petroleum contaminants in rivers and oceans is a significant threat to human health, as well as to many animal species. A current challenge for most industries and conventional effluent treatment plants is compliance with accepted disposal standards for oil-polluted wastewater. Of particular importance is the processing of dispersed oil in water, as well as oil in water emulsion. Conventional oil and water separation methods for processing oil in water contamination have several technology gaps in terms of applicability and efficiency. The removal and effective processing of dispersed oil and emulsions from oily wastewater is a costly and significant problem. The objective of this paper is to provide a review of the principles associated with oil in water emulsion separation, with the aim of providing a more definitive understanding of the terminology, processes, and methodologies, which will assist the development of a more efficient, innovative and environmentally friendly process for the separation of oily wastewater.
Shear enhanced flotation separation technology for winery wastewater processing
(University of the Western Cape, 2024) Vlotman, David Eswald; Bladergroen, Bernard
The agricultural industry requires and uses a significant quantity of fresh water around the world. Copious amounts of fresh water are used to make commercial wine, and an extensive amount of wastewater is generated through different processes during the production of wine. Winery wastewaters often have high levels of chemical oxygen demand (COD), total suspended solids (TSS), and an acidic pH ranging from 2 to 5. Additionally, they may also have varied levels of salinity and nutrients. Winery wastewaters possess inherent chemical qualities that make it a possible threat to the environment if not handled and discarded in a suitable manner. This research investigates the implementation of hydrodynamic shear with coagulation, flocculation and air flotation using a technology called shear enhanced flotation separation (SEFS) to destabilize and separate particulate matter in winery wastewater. The individual and synergistic effects of hydrodynamic shear, coagulation, flocculation and flotation in processing winery wastewater was evaluated. Previous studies have shown the effectiveness of coagulation, flocculation and flotation in treating winery wastewater, however, to date, limited research has been conducted to evaluate the effectiveness of a hybrid technology, which includes hydrodynamic shear to treat winery wastewater.
Synthesis & characterization of yttria-stabilised zirconia (YSZ) hollow fibre support for Pd based membrane
(University of the Western Cape, 2013) Bridget, Tshamano Matamela; Onani, Martin; Bladergroen, Bernard
Inorganic based membranes which have a symmetric/asymmetric structure have been produced using an immersion induced phase inversion and sintering method. An organic binder solution (dope) containing yttria-stabilised zirconium (YSZ) particles is spun through a triple orifice spinneret to form a hollow fibre precursor, which is then sintered at elevated temperatures to form a ceramic support. The phase inversion process for the formation of hollow fibre membranes was studied in order to produce the best morphological structure/support for palladium based membranes. The spinning parameters, particle size, non-solvent concentration, internal coagulant as well as the calcination temperature were investigated in order to determine the optimum values. Sintering temperature was also investigated, which would yield a sponge-like structure with an optimized permeability, while retaining a smooth outer surface. The supports produced by phase inversion were characterized in terms of dimension by mercury porosimetry, compressed air permeability, Surface Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The morphology of the produced ceramic support showed either dense or porous characteristics governed by the dynamics of the phase inversion process. The particle size of YSZ was examined in order to decrease the amount of agglomerates in the spinning suspension. Zetasizer tests indicated that at 15 minutes, the ultrasonic bath effectively homogenised the YSZ particles and prohibited soft agglomerates from reforming in the spinning suspension. In this study, an increase in air gap had no noticeable effect on the finger like voids but it had a considerable effect on both the inner diameter (ID) and outer diameter (OD) of the green fibres, while an increase in bore liquid flow rate and extrusion pressure promoted viscous fingering and significant effect on the ID and OD of the fibres, respectively. There was a decrease in porosity and permeability with increasing sintering temperature, addition of water concentration in the spinning suspension and varying N-methylpyrrolidone (NMP) aqueous solution of the internal coagulant. The amount of YSZ added to the starting suspension influenced the properties of the support structure. Viscous deformation was observed for dope with lower particle loading thus resulted in the formation of cracks and defects during sintering.
Synthesis and characterisation of sulphonated polyethersulphone membrane materials
(University of Western Cape, 2020) Boukili, Aishah; Bladergroen, Bernard
With current climate change, growing population, and rapid industrialization of developing countries, water is increasingly becoming a scare resource. Within a power plant, processes that consume most water are demineralized water production (boiler make-up), heat rejection (cooling) and emission control (wet flue gas desulfurization). Eskom’s fleet of existing coal-fired power plants are not equipped with SO2 abatement technologies and therefore retrofitting of the plants will be required to meet the compliance levels for SO2 emissions.
Technological advances in winery wastewater treatment: A comprehensive review
(Stellenbosch University, 2022) Vlotman, David; Key, David; Bladergroen, Bernard
The commercial production of wine is directly linked to the use of large amounts of fresh water coupled with the generation of copious amounts of wastewater containing significant amounts of organic and inorganic substances. The impact of this waste stream on the environment has required the wine industry to implement certain protocols in wastewater management to comply with respective effluent discharge regulations as set out by local authorities. Reduced accessibility to good quality water resources in recent years has forced wineries to consider more efficient wastewater management strategies to improve water recovery and re-use, thereby promoting more sustainable wine production and minimizing the impact on stressed water resources. This review presents a comprehensive overview of established and emerging, physicochemical, biological, advanced oxidation and hybrid wastewater treatment technologies specifically applicable to the wine producing industry. Herein, winery wastewater composition and treatment techniques, environmental implications, knowledge gaps, technological operational challenges, alternative disposal and recycling options of treated winery wastewater are critically evaluated.

Browsing by Author "Bladergroen, Bernard"

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