Environmental sustainability
Address environmental challenges, conserve ecosystem and secure the future resources.
Purification of water from Cu using agriculture waste
Water & wastewater treatment process technology
Metal contamination in water is a widespread ecological problem that can lead to various health hazards. Copper is one of the common contaminants in water whose concentrations continue to elevate due to high industrial activities. To date, adsorption can be considered an efficient method for removing metals, with one direction of development being the synthesis of green adsorbents. This work demonstrated the utilization of cellulose from waste to synthesize adsorbent for copper. Rice husk is utilized as the cellulose source for preparing hydrogel, and then incorporation of zeolite was done to enhance the surface area and porosity. Adsorbent preparation was performed by first dissolving rice husk cellulose in NaOH/urea to form cellulose gel. Then, zeolite was incorporated at a mass ratio of cellulose-to-zeolite of 4:2. Finally, a crosslinking agent was added to obtain the hydrogel composite. The presence of exfoliated clay particles in the hydrogel matrix was revealed through scanning electron micrograph imaging. The additional functional groups due to the addition of zeolite particles in the hydrogel were analyzed using the Fourier transform infrared spectroscopy technique. The resulting hydrogel composites were applied for the removal of Cu2+ from water. The effect of pH level, contact time, and coexisting metal ions on adsorption effectiveness was investigated. X-ray photoelectron spectroscopy analysis was performed to get insight into the adsorption mechanism. Adsorption kinetics reveals that adding zeolite allows more rapid adsorption of Cu2+; based on the pseudo-first-order parameter. However, incorporating zeolite contrarily affected the adsorption capacity, where it was decreased from 17.05 to 10.77 mg gô€€€ 1 for the adsorption process at 30 â—¦C. This work presents a novel approach to upcycling agrowaste, offering a sustainable solution for mitigating metal contamination in water.
Check out the article at Industrial Crops and Products 210 (2024) 118179
Metal-phenolic network coated-adsorbent
Water & wastewater treatment process technology
Surface modification of durian rind cellulose (DCell) was done by utilizing the strong coordination effect of polyphenol-based metal phenolic networks (MPNs). MPNs from Fe(III)-tannic acid (FTN) and Fe(III)-gallic acid (FGN) were coated on DCell via a self-assembly reaction at pH 8, resulting in adsorbent composites of FTN@DCell and FGN@DCell for removal of Cr(VI). Batch adsorption experiments revealed that FTN coating resulted in an adsorbent composite with higher adsorption capacity than FGN coating, owing to the greater number of additional adsorption sites from phenolic hydroxyl groups of tannic acid. FTN@DCell exhibits an equilibrium adsorption capacity at 30°C of 110.9 mg/g for Cr(VI), significantly higher than FGN@DCell (73.63 mg/g); the adsorption capacity was increased at higher temperature (i.e., 155.8 and 116.8 mg/g at 50°C for FTN@DCell and FGN@DCell, respectively). Effects of pH, adsorbent dose, initial concentration, and coexisting ions on Cr(VI) removal were investigated. The kinetics fractal-based model Brouers-Sotolongo indicates the 1st and 2nd order reaction for Cr(VI) adsorption on FTN@DCell and FGN@DCell, respectively. The isotherm data can be described with a fractal-based model, which implies the heterogeneous nature of the adsorbent surface sites. The Cr(VI) adsorption via surface complexation with phenolic hydroxyl groups was confirmed by evaluating the functional groups shifting. FGN@DCell and FTN@DCell were found to have good reusability, maintaining over 50 % of their adsorption efficiency after four adsorption-desorption cycles. Environmental assessment with Arabidopsis thaliana demonstrated their potential in eliminating the Cr(VI) phytotoxic effect. Thus, this study has shown the efficient and economical conversion of durian waste into environmentally benign adsorbent for heavy metal treatment.
Check out the article at Journal of Hazardous Materials 464 (2024) 132973