Journal of Water and Environmental Nanotechnology
Year:2018 | Volume:3 | Issue:4|Papers Count:8

In this study, a novel Halloysite nanotube/ferrihydrite (HNT/FH) nanocomposites have been synthesized using simple chemical precipitation method. The prepared nanocomposites were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, Transmission Emission Microscopy (TEM), Energy Dispersive X-Ray Spectroscopy (EDX) and Brunauer-Emmett-Teller (BET). The morphology of the synthesized nanocomposites revealed the attachment of FH to the lining of HNT. XRD patterns revealed the nanocomposite having a monoclinic structure which agrees with the FTIR results. The high surface area of 328. 6 m2/g and high aspect ratio of the nanocomposites endowed it with enforcing ability and enhanced water absorption capability, which in turn makes it highly hydrophilic. The high hydrophilic and adsorption ability of the novel nanoparticles has opened a wide opportunity for it to be utilized in the separation of wastewater.

Pristine and Se doped ZnO nanoparticles (NPs) were successfully synthesized by the thermo-mechanical method and their structural, morphological and optical properties are characterized. Here in, a series of experiments were carried out where cholesterol is treated with the same concentration of Pristine as well as Se doped ZnO NPs. Several Cholesterol oxidation products (COP's) such as 25-hydroxycholesterol and 26-hydroxycholesterol, 7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol are formed as observed by HPLC analysis. The batch of 5 wt % Se doped ZnO NPs exhibited highest cholesterol degradation efficiency followed by pristine ZnO NPs and 2 wt % Se doped ZnO NPs. The peak area corresponding to 7-ketocholesterol and 25-hydroxycholesterol is found to be 200980 AU and 200986 AU respectively. The mechanism of cholesterol degradation was correlated with the incorporation of oxygen vacancies due to Se doping, which was likely intermediate levels for transiting photoexcited charge carriers for generation of hydroxyl radicals. Further, hydroxyl radicals generated during the interaction of ZnO nanoparticles with aqueous media have been determined using terephthallic acid assay and 2', 7'-di-chlorofluorescein (DCF) assay.

Consistent with the US Environmental Protection Agency, heavy metals are classified as carcinogenic to humans. Their numerous agricultural, industrial, domestic, medical, and technical requirements have resulted in their widespread dissemination in the environment. This article examines a new green adsorbent for the removal of two hazardous heavy metals, lead, and mercury. The impact of contact time, pH, initial concentration, and temperature on the adsorption capacity of Pb were evaluated. Experimental data were analyzed by adsorption models. The equilibrium data were well adapted to the Langmuir adsorption model. The results show that the adsorption is homogeneous and localized in a monolayer. In addition, the maximum adsorption capacity was 277. 78 mg/g for Pb 2+ and Hg 2+ and 64. 52 mg/g for Hg 2+ 2+ from Langmuir isotherm. Thermodynamic data, including free energy (Δ G° ), enthalpy (Δ H° ), and entropy (Δ S° ) variations were also considered. The important point is that the negative value of Δ G° signifies the spontaneity of the adsorption process of the heavy metals-NiO/ZSM-5 system.

Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated the literature. Response surface methodology (RSM) in combination with eliminate the D-optimal design was applied to optimize the synthesis and evaluate the Photoluminescence (PL) intensity as the response which is described by a reduced quadratic equation. The relationship between the PL intensity and independent variables (ligand/precursor, reaction time, reaction temperature, pH, and precursors ratio) was investigated using reduced quadratic polynomial equation. The produced QDs in the optimum condition were analyzed by UV-Vis, FESEM, and FTIR. The results showed that the nanoparticles have a high PL intensity and a red shift in both emission and absorption spectra which is a splendid point for their applications, especially in bioimaging. The interaction between variables was not significant and the temperature was the most effective variable of PL intensity. A good agreement between model predictedand experimental data confirmed the correlated model.

In this study, we have synthesized a new Fe3 O4 /AC nanocomposite using low-cost adsorbent by microwave assisted in situ co-precipitation technique that was used as an effective adsorbent for the removal of methylene blue (MB) using the Taguchi design method as an optimization strategy. The optimum parameters are pH 7, Fe3 O4 /AC nanocomposite dose 0. 03 g, contact time 30 min, initial concentration of MB 25 mg/L and temperature 298 K. The obtained results of ANOVA show that their percent contribution in descending order is pH (66. 81%) > adsorbent dose (25. 54%) > temperature (4. 83%) > initial MB concentration (1. 23%) > contact time (0. 32%). The kinetic data were fitted to the pseudo-first-order, pseudo-second-order and intra-particle diffusion models and adsorption of MB dye followed pseudosecond-order kinetics. The obtained values of regression coefficient for Langmuir (0. 98), Freundlich (0. 93) and Dubinin-Radushkevich (0. 94) showed that adsorption process fits to the Langmuir isotherm and the maximum adsorption capacity is 384. 6 mg/g. Moreover, the thermodynamics studies suggested the spontaneous nature of the adsorption process.

The green synthesis of palladium oxide nanoparticles using Dictyota indica seaweed extract was investigated. Dictyotales is a large order in the brown algae (class Phaeophyceae). The color of the reaction mixture changed which indicated the formation of palladium oxide nanoparticles. UV-Visible, SEM, TEM, XRD, and FTIR analysis determined the characteristics of synthesized nanoparticles. The UVVisible analysis showed the formation of palladium oxide nanoparticles. SEM and TEM analyses presented the palladium oxide nanoparticles have a spherical shape and based on DLS analysis with the average particle diameter of 19nm. The comparisons of the nanoparticle size with different biological synthesis were studied which revealed this methodology offers the smallest size. The crystallographic parameters of the synthesized Pd nanoparticles were as follows: crystalline structure (cubic), space group (Fm-3m), and lattice parameter (a=5. 6500, b=5. 6500, c=5. 6500, α =90, β =90, and γ =90). FTIR analysis indicated the presence of a palladium oxide group in the product. The removal efficiency of cadmium by the palladium oxide nanoparticles was investigated to optimize the pH, contact time, dose of adsorbent and concentration of cadmium. The results showed that optimum conditions for cadmium removal from water were obtained at pH 8, 500 mg/l adsorbent dose and 20 min contact time, wherein in these circumstances the removal of cadmium was 82. 82%. The adsorption isotherms primacy was as follows, Langmuir R 2 =0. 9904> Freundlich R 2 =0. 9857> Temkin R 2 =0. 8791.

In the present work, Graphene Oxide (GO) nanoparticles with 0. 1, 0. 2, 0. 4 and 0. 8 weight percentages (wt. % ), synthesized by Hummer method entered into the Di-Calcium Silicate (C2 S) matrix (synthesized with using Pechini method and their nanostructural and mechanical characteristics studied by XRD (X-ray diffraction), FTIR (Fourier transform infrared), GPS 132 A, 4-probe techniques and emission factor analyses. To study and examine GO-C2 S nanocomposites as an environmentally-friendly Material for Sustainable Development of Cement Structure 4-capacitor form, with Metal (Al) /GO-C2 S composite/ Si substrate, is fabricated. The quality factor and dissipation factor were measured by GPS 132 A tool. The obtained results show that the sample with 0. 4% wt. of GO nanoparticles has a 0. 625 fraction emission factor and higher quality factor (32. 4), measured at two frequencies of 120 KHz and 1 KHz. Therefore C2 S/ GO nanocomposite with 0. 4 wt. % GONs can be therefore introduced as a good additive to reduced emission factor for production of cement and dissipation factor.

Given the gradual development of drug resistance in different bacterial species, it is necessary to search for new drugs with effective broad-spectrum antimicrobial activity. Therefore, recent studies on various nanometal oxides such as copper oxide and on antibacterial peptides including nisin as antibacterial agents are especially important. The present study aimed to investigate the synergistic effect of nisin-conjugated copper oxide nanoparticles (CuO NPs) on the genome of E. coli selected as a Gram-negative model. After being cultured in a Nutrient Broth medium, the bacteria were treated with CuO NPs at 15, 30, 40, and 60μ g/mL, with nisin at 30, 60, 90, and 120μ g/mL, and with nisin-conjugated CuO NPs at 10, 20, and 30μ g/mL and were then incubated. The optical densities of the samples were read at 600nm and their DNA was extracted. RAPD-PCR was used to study genomic effects, and statistical analysis was performed employing NTSYS-PC based on the DICE coefficient, the similarity matrix, and the drawn dendrogram. Results showed that the combination of CuO NPs and nisin had synergistic effects and was able to inhibit growth more than either of them used alone. However, this combination had no synergistic effects on the genome and caused minimal changes in the DNA sequence.