Durian peel is among the renewable biomass wastes abundantly available in Malaysia. An implication of untreated biological materials for biosorption process was intensively reported, that prioritize our work towards sorbent modification. The biosorption potentials of hydrochloric acid (HCl) modified durian peels (HAMDP) for removal of Zn (II) from simulated wastewater was investigated. Characterization of HAMDP was performed by ATR-FTIR, SEM and BET. Spectroscopic studies showed the predominant contributors for Zn (II) biosorption on HAMDP is attributed to hydroxyl, carbonyl, carboxyl and amides groups. Batch adsorption studies revealed optimum conditions of pH 8, 0.5 g biosorbent dose, 4 h contact time and reaction temperature of 313 K. Nonlinear isotherm models suggested applicability of Tempkin and Langmuir models at 313 K. The Langmuir maximum adsorption capacity was 36.73 mg/g. Kinetic studies revealed applicability of pseudo-second-order model. Webber-Morris model indicated possible role of diffusion of Zn (II) within the particles of HAMDP during the sorption process. Freundlich constant and activation energy values confirmed the physical nature of the process. Thermodynamic studies indicated that the process is exothermic and spontaneous. Regeneration studies depicted that HAMDP is economically viable. Conclusively, HCl served two significant purposes, namely; a good modification reagent and best eluent in Zn (II) recovery. Therefore, HAMDP is relatively effective, efficient, economical and most importantly "renewable and sustainable" biosorbent for Zn (II) removal from wastewater.

Chemical composition and flocculation efficiency were investigated for a commercially produced tannin - based coagulant and flocculant (Tanfloc). The results of Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive Spectroscopy (EDX) confirmed what claimed about the chemical composition of Tanfloc. For moderate polluted municipal wastewater investigated in both jar test and pilot plant, Tanfloc showed high turbidity removal efficiency of approximately 90%, while removal efficiencies of BOD and COD were around 60%. According to floc size distribution, Tanfloc was able to show distinct performance compared to Polyaluminum chloride (PAC). While 90% of flocs produced by Tanfloc were smaller than 144 micron, they were smaller than 96 micron for PAC. Practically, zeta potential measurement showed the cationic nature of Tanfloc and suggested coincidence of charge neutralization and another flocculation mechanism (bridging or patch flocculation). Sludge Volumetric Index (SVI) measurements were in agreement with the numbers found in the literature, and they were less than 160 mL/g. Calcium cation as flocculation aid showed significant improvement of flocculation efficiency compared to other cations. Finally Tanfloc showed competing performance compared to PAC in terms of turbidity, BOD and COD removal, floc size and sludge characteristics.

Gallic acid (GA) is a natural phenolic compound with therapeutic effects that are often challenged by its rapid metabolism and clearance. Therefore,  GA was encapsulated using gum arabic into nanoparticles to increase its bioavailability. The formulated nanoparticles (GANPs) were characterized for physicochemical properties and size and were then evaluated for antioxidant and antihypertensive effects using various established in vitro assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide scavenging (NO), β-carotene bleaching and angiotensin-converting enzyme (ACE) inhibitory assays. The GANPs were further evaluated for the in vitro cytotoxicity, cell uptake and cell migration in four types of human cancer cell lines including (MCF-7, MDA-MB231) breast adenocarcinoma, HepG2 hepatocellular cancer, HT-29 colorectal adenocarcinoma, and MCF-10A breast epithelial cell lines. The GANPs demonstrated potent antioxidant effects and have shown promising anti-cancer properties in a dose-dependent manner with a predilection toward HepG2 and MCF7 cancer cells. The uptake of GANPs was successful in the majority of cancer cells with a propensity to accumulate in the nuclear region of the cells. The HepG2 and MCF7 cancer cells also had a significantly higher percentage of apoptosis and were more sensitive to gallic acid nanoparticle treatment in the cell migration assay. This study is the first to confirm the synergistic effects of gum arabic in the encapsulation of gallic acid by increasing the selectivity towards cancer cells and enhancing  the antioxidant properties. The formulated nanoparticles also had remarkably low toxicity in normal cells. Based on these findings, GANPs may have promising therapeutic applications towards the development of more effective treatments with a probable targeting precision in cancer cells.

No abstract

No abstract