Sobia Naseem,Muhammad Rizwan,Wahidah H. Al-Qahtani,Ayesha Sadiqa,Awais Ahmad
Recycling food waste to extract valuable bioactive compounds (BAC) offers a groundbreaking solution to mitigate environmental challenges. The isolation and purification of BAC from food waste are getting more attention to maintain environmental sustainability. The therapeutic potential of these compounds highlights the need for innovative approaches to extracting and purifying them from by-products. In this context, the chlorogenic (CG) acid is extracted from watermelon (Citrullus lanatus) rind (WMR) using ultrasound-assisted extraction (USAE) technique and purified using the macroporous adsorption resin (MPAR) method. The extraction and purification were carried out with water, 70 % v /v ethanol/water (70 % Et), and 90 % v/v ethanol/water (90 %-Et) solvent to analyze the impact of solvent on extraction efficiency, purity, and recovery. The extracted CG acid was qualitatively analyzed via UV spectrometry and HPLC and underwent FESEM analysis while purified CG acid was characterized via FTIR and thermal analysis. The implementation of the MPAR method notably increased the yield to 4.6 mg/g of raw material using solvents comprising 90 % ethanol than water and 70 % ethanol. The recovery of CG acid significantly escalated to 88 %, enhancing the purity percentage from an initial range of 70–94 %.
Water splitting is the most potential method to produce hydrogen energy, however, the conventional electrocatalysts encounter the hindrances of high overpotential and low hydrogen production efficiency. Herein, we report a carbon-based nanocomposite (denoted as CCW-x, x stands for the calcination temperature) derived from watermelon peels and CoCl2, and the as-synthesized CCW-x is used as the electrocatalyst. The overpotential and the Tafel slope of CCW-700 for oxygen evolution reaction (OER) is 237 mV at 10 mA cm–2 and 69.8 mV dec–1, respectively, both of which are lower than those of commercial RuO2. For hydrogen evolution reaction (HER), the overpotential of CCW-700 (111 mV) is higher than that of the widely studied Pt/C (73 mV) but still lower than those of lots of carbon-based nanomaterials (122–177 mV). In the light of CCW-700 is highly active for both OER and HER, we assembled a water-splitting electrocatalyst by employing nickel foam loaded with CCW-700 as the anode and cathode in 1 M KOH. The water-splitting voltage is only 1.54 V for the CCW-700//CCW-700 electrodes and 1.62 V for the RuO2//Pt/C ones. Therefore, the so-denoted CCW-x powder possesses good electrocatalytic hydrogen production efficiency.
The release of volatile organic compounds (VOCs) during the production, storage, and transportation of petroleum and its derivatives can be hazardous to human health and lead to secondary pollution. Addressing this challenge, this study introduces a sustainable and low-energy approach for synthesizing high-efficiency porous carbon materials, leveraging the abundant and renewable watermelon rinds as a carbon source. The carbonization and activation processes were optimized to minimize energy consumption while maximizing adsorptive performance. In this research, watermelon rinds were used as a source of carbon production, and melamine phosphate (FR-MP) was employed as a modifying agent. The FR-MP modified porous biomass-derived activated carbon (PWAC) was created by subjecting it to physical milling, carbonization, and activation. This approach not only utilized a waste biomass effectively but also reduced the overall carbon footprint of the production process. An examination of the effects of FR-MP dosage on the pore structure , surface chemical properties, and VOCs adsorption abilities of PWAC revealed that a higher FR-MP dosage resulted in a wider range of pore sizes within PWAC. The incorporation of FR-MP intensified the development of internal porosity and pore expansion in PWAC. Specifically, the optimized PWAC-0.3 exhibited a significant increase in specific surface area (3149 m²/g) and pore volume (1.76 cm³/g), enhancing adsorption capacities for acetone and n-hexane up to 1046 mg/g and 760 mg/g, respectively. Furthermore, the PWAC demonstrated exceptional recyclability, maintaining 97% of its original adsorption capacity after five cycles, underscoring its sustainable and economic viability. The highly advanced hierarchical ultra-meso-macroporous structure of PWAC significantly reduced the diffusion resistance of VOCs, guaranteeing swift mass transfer and desorption of VOCs. Consequently, the developed PWAC represents a novel, cost-effective, and environmentally-friendly approach for VOCs adsorption, aligning with the principles of green chemistry and low-energy consumption. This research not only provides a promising solution for VOCs mitigation but also highlights the potential of waste biomass in producing high-performance carbon materials.
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