Journal of Water and Environmental Nanotechnology
Volume:5 Issue: 3, Summer 2020

This article reports the green synthesis of titanium dioxide nanoparticles (TiO2 NPs) from aqueous leaf extract of Trema Orientalis (L) and its effectiveness in photodegradation process of zoxamide under UV irradiation(λ max ≥ 250 nm) . Titanium (IV) isopropoxide act as the precursor and leaf extract act as the reducing agent. The synthesized TiO2 NPs are confirmed by the powder X-ray diffraction (XRD) analysis and the crystalline size was calculated by the Scherrer’s formula(52nm) and as well as Williaman-Hall(W-H) equation(59 nm). The Dynamic Light Scattering (DLS) analysis shows the stability and particle size approximately 88-94 nm of the synthesized TiO2 NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirms the presence of various functional groups in the synthesized NPs. The UV absorption wavelength observed at the peak of 351 nm and the calculated energy band gap is found to be 3.27eV. The surface morphology of the synthesized TiO2 NPs is determined by using Scanning Electron Microscopy (SEM). The rate of photodegradation of zoxamide in acetonitrile/water solvent system followed pseudo first-order kinetics, and calculated half-lives were found to be in the range of 2.33 -10.46 h. From this study, one photoproduct was isolated and characterized on the basis of column chromatography, mass spectral data and X-ray crystallography. The isolated photoproduct was identified as 3,5-dichloro-4 methyl benzoic acid. The plausible mechanistic pathway of formation of the photoproduct is also depicted. Langmuir–Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide photodegradation in presence of TiO2 NPs under UV irradiation.

The aim of this work is to exploit low cost and efficient sorbent for removal of heavy metals from the aqueous solution using Mallet Flower Leaf Powder (MFLP). MFLP is processed into a fine powder and used as a bio-adsorbent. Experiments are conducted to find out the feasibility of metal recovery process to reclaim the metals. The adsorption rates of both Chromium and Copper are lowered by 3.4% and 48.4% respectively in contrast to those obtained when only one metal is present in the solution. The presence of Copper along with Chromium has not much affected the adsorption rates of Chromium. There is higher adsorption rate for Chromium than for Copper at different temperatures. In the binary system, the copper adsorption rate is found to be suppressed by the presence of Cr(VI). The uptake of Cr(VI) is higher in the binary system than the single system, while the uptake of Cu(II) is lower in the binary system than the single system. The effect of initial concentration on recovery of Cu(II) from loaded adsorbent decreases up to 60 mg/l where about 68% recovery was found. The maximum recovery for Cu(II) was found to be at an adsorbent dosage in the range 15-35 g. As the initial concentration of Cu(II) increases, the retention of metal on MFLP increases. The data collected are verified with the kinetic studies. The results suggested favorable removal efficiency of copper and chromium from waste water using MFLP.

It is unquestionable that the employment of nano technology in every enterprise depicts a future for sustainable development due to the cheap and clean availability of nano materials. Evidently the researchers have largely centered on the blessings of the nano materials in cosmetics and food industries failing to center the negative effects it can impose on human fitness and environment. Titanium dioxide (TiO2) is one such nano particle that despite its elite properties is responsible for generation of oxidative stress. This review compiles some significant research carried out for the assessment of accelerated oxidative stress markers and the presence of Titania traces in human samples and sea organisms manifesting how they are damaging the living mechanisms. The elimination of the nanoparticles into the environment somehow advances towards land and water contaminating the soil, rivers and oceans having a derogatory effect on the natural running phenomena of soil organisms, sea algae and mussels. This review presents the latest findings and indicates making some strategies for reducing the use of the nano materials to a significant but limited amount making sure that it is not liable to any impairment to the humans and the surroundings.

< p>Membrane hybrid processes represent innovative separation technologies in which each technique complements the advantages and overcomes the challenges of the other. Dye removal from wastewater is an application for which membrane hybrid processes are widely applied. The focus of this study is also on development of a membrane hybrid process for dye removal from wastewater. Different proportions of NH2-MIL125(Ti) were embedded in a PSf polymeric membrane through the phase inversion method and the membrane performance was evaluated for the degradation of a Methylene Blue dye under three different light conditions of dark environment, UV and visible light irradiation. The synthesized membranes were characterized by FTIR, XRD, and FE-SEM measurements. NH2-MIL125(Ti) nanoparticles were successfully entrapped in the PSf membrane through a simple phase inversion method and addition of NH2-MIL125(Ti) to the PSf membrane resulted in the improvement of membrane porosity. Up to 60% of dye degradation was observed with the 1% NH2-MIL125(Ti)/PSf nanocomposite membrane after 300 minutes of UV light irradiation. Degradation kinetics followed a pseudo first order model, evidence of possible changes in the membrane properties upon irradiation with simulated solar radiation.

In this work, polyamidoamine dendrimer G(1.5) supported on SBA-15 nanoporous is used as a novel sorbent for extraction and determination of Pb2+ and Cu2+ ions from environmental water specimens utilizing flame atomic absorption spectrometry. FTIR spectrum and thermal analysis were used to represent the existence of dendrimer groups in the silica framework. The various parameters like pH, concentration of eluent, extraction time, interfering ions on extraction efficiency were studied. Pb2+ and Cu2+ ions were completely extracted at pH= 5-8 after stirring for 5 minutes. The minimum quantity of acid for stripping the ions from SBA- G1.5 was examined and the pre-concentration factor of the technique was 233 for both of ions. Under the optimized conditions the linearity of the technique was within 10-40 ng mL−1 Pb2+ and 2-20 ng mL−1 Cu2+. Detection limits for Pb2+ and Cu2+ were 5.0 and 1.2 ng mL-1 and the relative standard deviations (RSD, %, C=15 ng mL-1, n=5) were 2.9 % and 2.1 %, respectively. There was a good consistency between the measured and added amount of Pb2+ and Cu2+ in spiked distilled water which shows good accuracy of the method. Capability of the method in real sample was tested in various water samples.

In this project, new magnetic Fucus vesiculosus (m-FV) nanoparticles with a high adsorption capacity of cationic dyes were prepared. To reach a nanocomposite with effective performance, Fucus vesiculosus (FV) was modified using ultrasound. Then, the Fe2+/Fe3+ ions were co-precipitated in situ to induce magnetic feature to FV particles. Solutions contaminated with the model cationic dyes, methylene blue (MB) and crystal violet (CV), were treated by employing m-FV particles. Study on time of dyes removal showed a fast removing rate of MB and CV, reaching equilibrium at 10 and 5 minutes, respectively. Analysis of experimental kinetic data by the pseudo-first-order and pseudo-second-order models indicated a well-describing of data by the pseudo-second-order model. The isotherm data of adsorption of both cationic dyes on m-FV were modeled and revealed a well-describing with the Langmuir model. According to the Langmuir model, maximum adsorption capacities of 577 mg/g for MB and 1062 mg/g for CV on m-FV observed. Easy recovery, good recyclability, pH-independent property, as well as the high capability in the removal of cationic dyes, the m-FV can be considered an effective and eco-friendly bioadsorbent in the treatment of dye contaminated solutions.

In this study adsorption of fluoride ion from high-fluorine solutions (<2000 ppm) using the natural and modified ground clinoptilolite is investigated. These low-cost adsorbents are carefully characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermos-gravimetry (TGA) and differential scanning calorimeter analysis (DSC). In order to enhance the fluoride removal capacity of natural zeolite, it is milled into nano-powders and modified using hexadecyltriammoniumions (HDTMA+ ). The kinetic, equilibrium, and thermodynamic of fluoride adsorption are measured and described by the well-known mathematical models. The Langmuir model is fitted to the experimental data of nano HDTMA-clinoptilolite with the average relative error (ARE) of 1.57%. According to Langmuir isotherm, the maximum adsorption capacity of nano clinoptilolite and nano HDTMA-clinoptilolite are determined 25.26 and 32.40 mg/g, respectively. The heat of fluoride adsorption onto the nano-clinoptilolite and nano HDTMA-clinoptilolite is calculated to equal to -82.57 and -60.46 kJ/mol, respectively. Kinetic studies indicated that fluoride adsorption rate on nano HDTMAclinoptilolite is higher than unmodified zeolite and it is modeled by the pseudo-second kinetic model.

Rice husk silica (RHS), an agriculture waste, was used as a silica source for MFI zeolite synthesis. Magnesium oxide (MgO) nanoparticles (NPs) were grown in zeolite substrates using a solid state reaction. The synthesized nanocomposite (NC) was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and transmission electron microscopy (TEM) techniques. The BET results demonstrated specific surface area of MgO/RHS-MFI NC was smaller than RHS-MFI zeolite. It was founded that magnesium oxide NPs can be encapsulated into pores of RHS-MFI zeolite. The most principal objective of this research was evaluation of the capability of photocatalytic process of MgO/RHS-MFI zeolite heterogeneous nanocomposite over methylene blue (MB) dye. The results showed the MB degradation reached 80 % under UV light at pH=9. RHS-MFI affected the photocatalytic activity of magnesium oxide due to decrease of recombination rate of the electro-hole in magnesium oxide semiconductor. A plausible oxidation mechanism was also proposed.