Journal of Water and Environmental Nanotechnology
Volume:6 Issue: 1, Winter 2021

In this study, p-n junction photocatalyst CuO/CeO2ZrO2 with different concentrations of CuO was prepared by auto solution combustion method using glycine as fuel. This method is simple, fast and cost effective compared with other preparation methods. The photocatalyst was characterized by X-ray diffraction (XRD), energy-dispersive spectrometer (EDS), UV-vis DRS. The assembly of p-type CuO nanoparticles produces a large number of nano p–n junction heterostructures on the surface of the CeO2ZrO2 nanocrystals, where CuO and CeO2ZrO2 form p- and n-type semiconductors. The experimental results reveal that p–n junction CuO/CeO2-ZrO2 heterojunction nanostructures exhibit much higher visible-light photocatalytic activities than the n-CeO2-ZrO2 for the removal of dye from industerial waste water. The photocatalytic activity of the p-n CuO/CeO2-ZrO2 heterojunction photocatalyst was evaluated using the degradation of aqueous methylene blue solution (MB) under visible light irradiation(λ>420 nm). The photo-degradation rate of this catalyzed is much faster than those occurring on n-type CeO2ZrO2. The sample with a p-n CuO/ CeO2-ZrO2 molar ratio of 0.021 presented the best photocatalytic activity, which was 30% higher than that of n-type CeO2ZrO2. The heat treatment condition also influences the photocatalytic activity strongly, and the best preparation condition is about 400ºC for 4h.

{[Dy(BTC)(H2O)]•DMF}n metal organic framework nanoparticles was synthezed through solvthermal method. The product was characterized by XRD, TG, BET, and SEM techniques. SEM images showed that the synthesized sample has semi-cubic particles with average size of 70 nm in length.For improve the gas separation performance,the MOF nano particles were dispersed in polydimethylsiloxane (PDMS) for preparation of mixed matrix membrane (MMM) on support of polyethersulphone (PES). The performance of obtained MMM in separation of NO, N2 and O2 gas were investigated, and the effect of MOF nanoparticles (5, 10, and 15% wt)and feed pressure (100-250 kPa) on permeability and selectivity were studied. It was found that the membrane performance is evaluated by addition of MOF nano particles in membrane (polymeric matrix), and the feed pressure have not important effect on separation. The performance (NO/N2 and NO/O2 selectivity) increased as the loading of MOF particles (up to 15% wt) being dispersed within the polymer matrices.

Monitoring the levels of toxic Hg2+ metal ion in aquatic environment is important issue because this ion can have adverse effect in human health and environment. Therefore, detection of Hg2+ ion in water is very important issue for improving human health and water quality. Metallic nanoparticles such as gold and silver nanoparticles (AuNPs & AgNPs) have received much attention due to their colorimetric properties as well as localized surface plasmon resonance (LSPR) properties. AuNPs and AgNPs can easily change their colour (AuNPs: Red to Pink/Blue; AgNPs: Yellow to orange/red) which is easily discriminate by visual inspection. Functionalization of AuNPs and AgNPs offers an excellent application in many scientific worlds as the choice of ligands/functionalizing groups is outmost importance for their colloidal stability and function of the nanoparticles. In this review, we have discussed the colorimetric sensors of gold and silver nanoparticles based on functionalization of organic ligands, polymers, amino acid, and proteins for the detection of Hg2+ ion in aqueous medium.

The present study aimed to synthesize copper oxide (CuO) nanoparticles (NPs), which were used as an adsorbent for the sequestration of Iron (Fe) (III) ion from aqueous solution. The synthesized NPs were characterized with the help of X-ray diffraction (XRD) spectroscopy, Field Emission scanning electron microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDS). The SEM and XRD analyses indicated the average size of CuO NPs were ~25 nm with a rod-like shape. Based on the batch experiments the maximum adsorption observed at pH 9 with removal efficiency 98.38%, initial metal ion concentration of 10 ppm, and contact time 60 min. This study also revealed that adsorption capacity increases when the concentration of adsorbents decreases. To specify the adsorption characteristics of CuO NPs, the adsorption equilibrium data were treated with Langmuir and Freundlich models, which demonstrated that the removal of Fe (III) ions was mostly favored by the physical process followed by the multilayer adsorption on the heterogeneous surface of the adsorbents. Finally, this study concludes that CuO NPs could be used as a promising material for the removal of Fe(III) ion from aqueous Solution.

Microwave assisted biosynthesis of nanoparticles has been a cost effective, environmentally benign, and alternative to the chemical method. In this context, we report eco-friendly and robust nanoparticles synthesized using the bio-waste (Banana leaves) extract material through a microwave method. The newly synthesized Banana Leaves extract -Silver Nanoparticles (BL-AgNPs) is confirmed by using the UV-Visible, FT-IR spectroscopy and Scanning Electron Microscopy (SEM) techniques. UV-Vis spectrum shows the widening of the band around 476 nm, which confirms the polydispersed nature of BL-AgNPs. FT-IR spectroscopy explores that, hydroxyl and carbonyl groups in the Banana Leaves extract play vital role in the reduction of silver ions and also attach with AgNPs. The phytochemical studies reveal that, the polyphenols and alkaloids present in the BL extract act as reducing and stabilizing agent, which is responsible for the reduction of Ag+ (silver ions) to Ag (BL-AgNPs) and stabilization of BL-AgNPs. This clearly confirms the formation of silver nanoparticles (AgNPs). SEM results revealed that, bead shape of BL-AgNPs with particle size of 80 to 100 nm. In conclusion, BL-AgNPs exhibits promising anticancer activity against lung cancer and breast cancer cell line by endorsing inhibition of cell migration and proliferation on low concentration.

Zinc is essential for aquatic biota including fishes at a lower concentration, but when it reaches higher concentration it becomes toxic. The objectives of the present work were related to the impact of different quantities of zinc oxide nanoparticles on the growth and hematology of Mrigal Cirrhinus mrigala. The zinc oxide nanoparticles were synthesized by chemical precipitation method and characterized using by UV-VIS, SEM, EDAX, FTIR and XRD. Different quantity of zinc oxide nanoparticles such as 0, 5,10,15,20 and 25mg/100g were prepared by using a fish meal, groundnut oil cake, wheat flour, and tapioca flour. Feed utilization and hematological parameters of Mrigal were estimated after 21 days of feeding. UV-visible adsorption spectra show that the peak absorbance of ZnO nanoparticles was observed 500 nm. SEM shows that nanoparticles formed are clustered because of the adhesive nature of flower-shaped appearance. EDAX shows that the zinc oxide nanoparticles and the peaks are located between 1.0Kev and 8.5Kev. The FTIR spectrum of zinc oxide nanoparticles was analyzed in the range of 400-4000cm-1 and spectral bands were observed. The XRD results were viewed as the crystalline nature and average size of zinc oxide nanoparticles. Survival rate indicated that all Mrigal were healthy during the period of 21 days except in feed II,IV, and V. The feed utilization and growth parameters are higher in feed IV. Hematological parameters such as hemoglobin, RBC, Hematocrit, MCV, MCH, MCHC of Mrigal progressively increased and WBC and platelets decreased with increase in the quantity of Zinc Oxide nanoparticles.

The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed to the mixed oxide. The SEM images approved Mg-Al LDH comprised of flakes and the calcined LDH comprised of spherical nanoparticles. BET results indicated the specific surface area of 100.2 and 86.3 m2.g-1 for pure LDH and calcined LDH, respectively. The process was optimized by one factor at a time method and considering four process factors i.e. reaction temperature, peroxide dosage, initial phenol concentration, and reaction time. The optimum conditions resulted at initial phenol concentration of 100 ppm, reaction temperature of 60 ºC, with peroxide volume of 3 mL and time on stream of 45 min over calcined LDH with maximum 85% removal of phenol. On the pure LDH, the maximum phenol removal (79%) resulted at peroxide volume of 2.5 mL at 55 min. The study concluded that the calcined Mg-Al LDH due to synergistic effect of MgO and Mg-Al mixed oxide showed higher catalytic activity despite a relatively low surface area.

Nowadays, green syntheses have received crucial attention as a reliable, developing and eco-benevolent protocol for synthesizing a broad range of nanomaterials (NMs) including metal/metal oxides NMs, bio-inspired materials and hybrid/composite NMs. As such, biogenic synthesis is regarded as a significant tool to mitigate the destructive impacts associated with the conventional approaches of synthesis for NMs generally utilized in industry and laboratory. In this review, we summed up the general protocols and mechanisms of green synthesis routes, especially for silver (Ag), silver oxide (Ag2O), cadmium (Cd), copper (Cu), copper ferrite (CuFe2O4), palladium (Pd), aceprophyline, cellulose and graphene nanomaterials/nanoparticles using cow urine. Importantly, we explored the main role of biological constituents which is existed in cow urine. These essential biomolecules act as reducing/stabilizing agents in solvent systems. The stability, phase formation and surface morphology of NMs using characterization techniques are also discussed. Finally, we covered the eclectic applications of such synthesized NMs in terms of anti-asthma, antimicrobial, antituberculosis, antioxidant, anticancer activity, catalytic activity and removal of pollutants dyes.