The study aims to develop an eco-friendly solution for addressing contaminants in hospital wastewater. To achieve this, banana peel, a cost-effective and easily available agricultural waste, was chemically modified using sulfuric acid and sodium hydroxide. The hospital wastewater was analyzed using an Atomic Absorption Spectrometer to identify the presence of heavy metals. The physicochemical properties were measured and compared against the standards set by the World Health Organization (WHO). Scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the chemically modified banana peel. Batch adsorption was conducted with the wastewater using the prepared adsorbent. The effect of contact time, mixing rate, temperature, and adsorbent dosage was examined to know the removal efficiency of the adsorbent. The experimental design incorporates Taguchi OA design to optimize the process. The total heavy metals discovered in the wastewater were As, Cd, Fe, Cu, Ni, Cr, Pb, Mn and Zn. The percentage of Cd, Fe, Cu, Ni, Cr and Pb removed were 79.5%, 87.9%, 56.9%, 89.0%, 88.5% and 93.5%, respectively, at temperature, adsorbent dosage, mixing rate and contact time of 30 °C, 3 g, 700 rpm and 60 min, respectively. The physicochemical properties remain within the acceptable WHO range except the turbidity. At optimum point, the percentage removal of Cd, Fe, Cu, Ni, Cr, Pb and Zn were 64.3%, 80.5%, 51.4%, 82.3%, 72.4%, 86.6% and 72.1%, respectively; while, the conductivity, pH, TDS, and turbidity value were, respectively, 20.57 mS/cm, 6.8, 10.16 mg/l, and 86.31 NTU. Characterization revealed the existence of active functional groups on the adsorbent surface enhancing the hospital wastewater treatment and change in its morphological structure after the treatment was noticed. In conclusion, the modified banana peel was effective for the treatment of hospital wastewater.

To curb environmental pollution emanating from the exhausts of engines using fossil diesel fuel (DF), studies on the use of biodiesel from renewable energy source are ongoing. However, engine components have been observed to corrode easily in biodiesels. In this study, a comparative study of the corrosion rate of aluminum coupon (AC) in biodiesel from waste cooking oil over chicken eggshell‐supported alumina catalyst (WCOB) and fossil DF was executed. Weight loss method was used to examine the corrosion rate. Highest corrosion rates of 0.0381 and 0.0052 mm year⁻¹ were recorded for AC in WCOB and DF, respectively. The developed mathematical models proved effective for corrosion rate prediction. At optimum prediction, the minimum corrosion rates for the AC in WCOB and DF were 1.822 × 10⁻³ and 1.222 × 10⁻³ mm year, respectively. Characterization revealed pits formation and presence of oxygen and carbon on AC surface with loss of Al ions from the AC surface into WCOB and DF after corrosion. In conclusion, all results revealed high corrosion rates of AC in WCOB than DF.

Awareness of the need to protect the environment and people's health has led to an intensification of concerns for obtaining sustainable products and processes. Toxic waste created during the production and use of synthetic dyes has an impact on both human and environmental health. As a result, natural dyes are more secure and safer than synthetic dyes. This study is significant because it has the potential to help develop sustainable and environmentally friendly textile dyeing techniques. In this study, a natural dye was successfully extracted from orange peel (Citrus recticulata Rutaceae) which was applied on textile fibre and was found to be partly effective for eco-friendly dyeing applications. The extracted dye does not have a good wash fastness, which is the ability of the fabric to retain its colour after washing. This weakness is demonstrated by carrying out a Fourier transform infrared (FTIR) analysis where the potential binding mechanisms between the dye and the textile fibres was revealed. Different functional groups can interact with the fibre’s functional groups, affecting the dye's affinity for the fabric and its overall colour fastness properties. Findings show that dyes from orange peels showed promise in this study, but need to be improved further. Therefore, the study suggests that further research is needed to optimize the dyeing process and improve the fabric's resistance to washing and other environmental factors.