Precious metal (palladium, platinum & gold) recovery by electronic waste recycling using cyclodextrin from starch extracted from non-edible plants
The project aimed at developing an environmentally friendly methodology for recovery of precious metals (platinum, palladium and gold) from electronic waste. Starting from starch extracted from yams and cassava, we were able to synthesize α-cyclodextrin (CD) using the enzyme α-cyclodextrin glucanotransferase from Escherichia coli. Without the need to purify and isolate the cyclodextrin, a one-pot process was possible where α-cyclodextrin formed a complex with gold (α-CD-Au) in a matrix of dissolved gold-containing-electronic waste and soil. Elemental gold was obtained from α-CD-Au complex by reduction with sodium thiosulphate. Sufficient recoveries of 22.9% and 70.8% of gold were achieved from E-waste and soil, respectively. Palladium could not be recovered by the proposed methodology while studies on platinum was hindered by the scarcity of platinum-containing waste. On the hand, palladium found with gold in most electronic plays a great role in catalysis enabling easy synthesis of many products. Palladium recoveries were too low compared to gold for a viable commercial application. Unfortunately, platinum recovery was not possible by our proposed methodology.
Smart Digital Laboratory of Chemical Sciences for Secondary and University Students
The project aimed at developing a smart digital laboratory for learners taking science subjects/courses at secondary schools, tertiary institutions and universities. The interface is designed on portable computers, and the recorded videos can be played on any media platform. Selected pre-conducted practicals were integrated with audio/visual guidelines and selected tutorials with question-answer modes for self-study and self-assessment by learners. The digital platform helps learners grasp the practical aspects not catered in the education handouts and broadcasted lessons. The software ensures safe distancing between tutors and students reducing the chance of spreading the novel coronavirus and future pandemics. It also enables institutions with poor laboratory facilities and inadequate personnel to conduct science practicals. Version 1 focussed on a digital chemistry laboratory interface which can be extended to other science subjects.
Providing Clean and Safe Water to Low-Income Communities using Activated Carbon-Cellulose membrane-based Water filters derived from Disposed Waste
The project will develop cheap and environmentally benign water filters to provide clean and safe water to communities without access to treated water. A water filter system made of natural materials from disposed waste will be constructed. Carbon residues in waste will be used to synthesize activated carbon which in combination with cellulose mainly from used paper and selected discarded carbohydrates will be used to build an activated carbon-cellulose membrane framework to serve as the main skeleton for the filter system. Selected natural adsorbents and the corresponding extracts will be incorporated. This will allow one-pot optimal adsorption and reverse osmosis in a phased manner and thus enabling stepwise removal of the majority of inorganic wastes especially heavy metals, and also the capture of persistent organic pollutants and their residues for instance most antibiotics and pharmaceuticals which find their way to the aquatic system from domestic and industrial activities and cannot be removed by convention water treatment processes nor most commercially available filter gadgets. The proposed filter system is green, cheap and less tedious to use compared to sophisticated water treatment devices and conventional water treatment methodologies that employ resins with complex organic molecules in ion-trap and exchange, which is expensive in design and also pose difficulties in disposal after use. This success of the proposed water system will provide clean and safe water to the vast population without access to treated water especially in rural areas and hardship centres like refugee camps. Status- On going