In this study, zinc oxide (ZnO) nanoparticle was synthesized by a novel route of microwave assisted method using ascorbic acid and PVA as capping agent and stabilizing agent. A prominent peak at 378 nm by UV absorption ensured the synthesis of ZnO nanoparticles. The crystalline property revealed that synthesized ZnO nanoparticle is highly crystalline having wurtzite structure. A significant band at ~ 498 to 557 cm −1 in FTIR was assigned to the characteristic stretching mode of Zn-O bond. EDX spectrum showed that ZnO nano particles were composed only with Zinc and oxygen. SEM image disclosed that ZnO nanoparticles were spherical in shape with an average particle size of 70-90 nm for the combined effect. The antimicrobial and ant-biofilm application of synthesized ZnO nanoparticle was studied against Salmonella typhi, Klebsiella spp. SK4, E. coli RN89, E. coli (gram-negative) and S. aureus-8a (gram-positive) bacteria and exhibited excellent activity against the strains. Prepared nanoparticle also found to possess outstanding photocatalytic activity against methylene blue degradation under sunlight with a T 50 and T 80 value of 71.44 and 165.87 min respectively.

The rapid growth of industrial and agricultural activities in Malaysia are leading to the impairment of most of the rivers in recent years through realising various trace metals. This leads to toxicity, particularly when the toxic has entered the food chain. Perak River is one of the most dynamic rivers for the Malaysian population. Therefore, in consideration of the safety issue, this study was conducted to assess the concentration of such metals (Cd, Cu, Zn, Fe, and Pb) in the muscles of most widely consumed fish species ( Barbonymus schwanenfeldii , Puntius bulu m, Puntius daruphani , Hexanematichthys sagor , Channa striatus , Mystacoleucus marginatus , and Devario regina ) from different locations of Perak River, Malaysia by employing inductively coupled plasma optical emission spectroscopy (ICP-OES). Among the trace metals, Fe and Cd were found to be the highest (29.33–148.01 μg/g) and lowest (0.16–0.49 μg/g) concentration in all of the studied species, respectively. Although the estimated daily intakes (μg/kg/day) of Cd (0.65–0.85), Fe (79.27–352.00) and Pb (0.95–12.17) were higher than their reference, the total target hazard quotients values suggested that the local residents would not experience any adverse health effects from its consumption. In contrast, the target cancer risk value suggested that all fish species posed a potential cancer risk due to Cd and cumulative cancer risk values, strongly implying that continuous consumption of studied fish species would cause cancer development to its consumers.

Green synthesis of nanoparticles is more preferable because of its flexibility in preparation as well as its capability to avoid utilization of toxic chemicals. This study was designed to synthesize silver nanoparticles from plant leaves of Calendula officinalis for utilizing it for the degradation of commonly used dyes. The maximum absorption of UV-Vis light at 436nm ensured the synthesis of silver nanoparticle. The various reducing agent present in plant leaves extract cause the formation of silver nanoparticles as ensured by the FTIR. The morphology study showed that the synthesized nanoparticles were 50-60 nm and 140-150 nm in size for 1mM and 2mM silver nanoparticles (Ag NPs) respectively. It has also been observed that the synthesized nanoparticles possess a high catalytic activity for the degradation of both methylene blue and methyl orange. The degradation data ensured that the reaction rate of degradation is size dependent and the highest degradation percentage (69.79% within 5 minutes), degradation rate (0.18 ± 0.03 min -1 ), half-life (T 50 = 3.85 min) and 80% degradation (T 80 = 8.94 min) was observed for 1mM Ag NPs in case of methyl orange.

Sawdust supported nano-zerovalent (NZVI/SD) iron was synthesized by treating sawdust with ferrous sulphate followed by reduction with NaBH 4 . The NZVI/SD was characterized by SEM, XRD, FTIR and Chemical method. Adsorption of As (III) by NZVI/SD was investigated and the maximum uptake of As (III) was found at pH value of 7.74 and equilibrium time of 3 hrs. The adsorption isotherm modelling revealed that the equilibrium adsorption data were better fitted with the Choudhury et al.; CSIJ, 29(1): 1-12, 2020; Article no.CSIJ.54285 2 Langmuir isotherm model compared with the Freundlich Isotherm model. This study revealed that the maximum As (III) ions adsorption capacity was found to be 12.66 mg/g for using NZVI/SD adsorbent. However, the kinetics data were tested by pseudo-first-order and pseudo-second-order kinetic models; and it was observed that the adsorption data could be well fitted with pseudosecond-order kinetics for As (III) adsorption onto NZVI/SD depending on both adsorbate concentration and adsorption sites. The result of this study suggested that NZVI/SD could be developed as a prominent environment-friendly adsorbent for the removal of As (III) ions from aqueous systems. Original Research Article

Over the last few decades, several studies have been undertaken to determine the benefits and drawbacks of various copper nanoparticle synthesis processes. Copper nanoparticles have garnered considerable attention because of their remarkable optical and electrical properties. CuNPs' optical, electrical and chemical characteristics are substantially depending on their synthesis procedures. Copper is less expensive than precious metals such as gold and silver, and it also possesses strong photocatalytic and antimicrobial competencies.In this review, synthesis of copper nanoparticles by various methods such as physical, chemical and biological is elaborately illustrated and in the meantime it's also explained how different reaction variables like temperature, pressure, reaction time, and reactor properties affect the size, shape, and surface area of produced copper nanoparticles. Moreover, photocatalysis and antibacterial mechanism for copper nanoparticles are also illustrated with proper illustration.