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 aimed at developing an efficient water filter system from agricultural waste and naturally existing materials for the removal of toxic heavy metals and organic residues mostly pharmaceuticals from polluted water. The filter assembly was made of a three-dimension silica material (xerogel), sand/quartz, gravel and activated carbon synthesized from banana peels, and other naturals materials including egg shells, pumpkin and moringa seeds as adsorbents. The optimized filter set-up removed >95% metal ions (lead, copper and zinc) and pharmaceuticals (tetracycline, caffeine, metronidazole and ciprofloxacin). It also significantly reduced coliforms in water and was able to remove Escherichia coli, a disease-causing microbe. The filter system was efficient up to 12 L in a laboratory setting with a filter time of an hour, and the adsorbent had a life-span and shelf-life of more than 6 months under normal storage. Field activities involved sample collection, real-field filter testing and dissemination and workshop to identify common metals ions and pharmaceuticals in water and conduct awareness campaign on dangers of polluted waters, pollution mitigation and the use and design of simple filters from locally available raw materials.