Journal of Water and Environmental Nanotechnology
Volume:9 Issue: 1, Winter 2024

In this study, the decomposition of BTA was examined using a photocatalytic process (UV/Fe2O3@Alg-TiO2). The effects of various operational parameters such as the initial pH(3-7-10), catalyst dosage (0.05, 0.1, 0.15 g/L), BTA initial concentration (15–45 mg/L), UV intensity ( 2, 4, and 6 watts), and detention time (15,30, and 45 minutes) on the decomposition of BTA in the reactor with Batch conditions and in deionized water, real wastewater (three different matrices saline water, and real raw wastewater after activated sludge and after stabilization ponds) were investigated. SEM, XRD, and FTIR determined the synthesized catalyst's specifications. The results showed that 73.5% of BTA and 30% TOC was removed during the UV/Fe2O3@Alg-TiO2 photocatalytic process at the optimal condition (BTA=30 mg/L, pH = 3, UV = 4 Watt and catalyst dosage = 0.15 g/L) in deionized water. Also, the efficiency of the process in removing contaminants from the Saline, real raw sewage after activated, and after activated sludge and stabilization ponds was 23%, 47%, and 51%, respectively. The results showed that the toxicity decreased in 200 minutes that if sufficient time is provided to complete the reaction toxicity can be reduced. The results related to the amount of electrical energy consumed showed that considering both the advantages of BTA removal efficiency and energy consumption, the best performance was obtained in optimum conditions.

A group of supramolecular solid materials known as "metal organic frameworks"(MOFs) are a type of hybrid networks made up of a variety of inorganic and organic linkers that are all tightly bonded to metal ions. These classes of compounds have a larger surface area with the benefit of variable pore sizes, a diverse structure, and a lovely appearance. They are promising materials for a range of applications because they are easy to develop and have consistent, fine-tunable pore structures. Controlled mixing of MOFs with functional materials is resulting in the development of new multifunctional composites and hybrids that display unique properties that outperform those of their component parts as a whole. The structural characteristics, classification, The most widely used and successful strategies for MOFs composite synthesis are presented like (Encapsulation method, Solvothermal method, Solution impregnation, and Click chemistry (reaction) method), numerous characterization techniques and their applications MOFs composite have all been covered in this review. Crystals with extremely high porosity and good thermal and chemical stability can be produced by carefully choosing the MOF ingredients. Because of these properties, MOFs composites can be used for a wide range of applications, including, sensing toxic chemicals, drugs, gases, and trace metals, components of foods and many more and also for detection of different materials. This is a rapidly developing interdisciplinary research area therefore to present the current situation of the field; this article has covered recent achievements as well as new avenues to investigate the future scope and uses of MOFs composites/hybride.

In this study, the flat sheet membranes including the neat polyethersulfone (PES) and the mixed matrix membranes (MMMs) containing 20 wt. % polyethersulfone (PES) and various amounts of Fe3O4 nanoparticles were prepared using wet phase inversion and conventional casting methods. Manganese ion rejection and permeate flux as a performance evaluation of the prepared membranes was studied and compared. The characteristics of the fabricated membranes and the synthesized nanoparticles were fulfilled by transmission electron microscopy, field emission scanning electron microscopy and contact angle measurement. The operational parameters such as polymer concentration, pressure, pH, manganese ion concentration and time for manganese ion rejection and permeability were firstly optimized on the neat PES membrane. In the next steps, the performance of the fabricated MMMs containing various amount of Fe3O4 nanoparticles and PES (20%wt.) was evaluated and compared under these optimized conditions. Under the optimal conditions obtained for the rejection of manganese ions by neat PES, the fabricated MMMs had better performance than the neat PES membrane. Also, the results showed that the best performance of the prepared MMMs with the manganese rejection percentage of 89.3% and permeate flux of 28.7 L.m-2.h was found to belong to the PES membranes containing 0.1 wt.% of Fe3O4.

Novel results in this study showcase the utilization of sunlight-dried, ground Lablab purpureus husk (LLPh), treated with water and alkali, as a highly efficient bio-adsorbent for the removal of cationic dyes from aqueous solutions. Methylene blue (MB), malachite green (MG), and crystal violet (CV) were effectively adsorbed onto NaOH activated LLPh (NaOH-LLPh) as bio-adsorbent. Employing the Chromatrap method within a column, successfully removed these dyes, while the surface morphology of the bio-adsorbent was elucidated through scanning electron microscopy (SEM) analysis. FTIR spectrometric data revealed valuable insights into the extent of adsorption. The impact of factors including adsorbate concentration, adsorbent dose, pH, contact time, and flow rate on the adsorption process was systematically studied and optimized. Up to 1000 µg/mL of MB and MG, 50 µg/mL of CV were found to be effectively removed by adsorption at pH 4-5, 3 and 2, respectively, at the flow rate of 1 mL/min. The results of kinetic studies and adsorption isotherms of above-mentioned dyes indicates that, all the three dyes follow the pseudo-second order kinetics. The adsorption of MB and MG are well fitted with the Langmuir isotherm model. The other dye CV suits with the Freundlich isotherm model. Based on the results, NaOH-LLPh, as an inexpensive and eco-friendly adsorbent, is suitable for the removal of cationic organic dyes from aqueous samples.

In this study, maghemite and magnetite nanoparticles were functionalized with cetyl trimethyl ammonium bromide(CTAB) surfactants, in order to obtain effective chromium removal from wastewater. X-ray diffractometry (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectrophotometry (FTIR) were used to characterize the functionalized nanoparticles. Various parameters, including pH, initial chromium concentration, added salt, and adsorbent dose, were evaluated in batch experiments to evaluate chromium removal efficiency. Adsorbent dose and chromium ions show a synergistic relationship with pH and the chemical and electrostatic interactions between cationic surfactant and negatively charged Cr(VI) ions. In both types of functionalized nanoparticles, Cr(VI) was efficiently removed at low pH values with CTAB@MNPs, but the pH increased negatively impacted the removal process. Additionally, Fe3O4@CTAB mainly adsorbs chromium chemically, reducing Cr(VI) to Cr(III), with less impact from competitive ions compared with γ-Fe2O3@CTAB.At pH = 2, adsorbent dose = 5 g/L, and initial chromium concentration = 1 mg/L, maghemite@CTAB achieved a high chromium removal efficiency of 95%. In contrast, magnetite@CTAB achieved a chromium removal efficiency of 95.77% in 7 minutes and 30 seconds at pH = 4, adsorbent dose = 12 g/L, and initial chromium concentration = 98 mg/L. Notably, magnetite outperformed maghemite by a factor of 100 in chromium elimination, which can be attributed to the presence of two adsorption mechanisms, chemical and physisorption, in magnetite nanoparticles, whereas maghemite only had physisorption.

Heavy metals are known to be toxic for living organisms even if they are present at low levels. Water pollution by heavy metals from industries is a dangerous environmental problem. Due to the ease, flexibility, and cost-effectiveness of the remediation process, adsorption has been widely implemented in heavy metal wastewater treatment. In the present study, nanostructured manganese oxide was used for the removal of the heavy metal ions from aqueous solutions by a batch adsorption method and have been modelled using classical Langmuir and Freundlich adsorption isotherms. we have successfully synthesized an efficient adsorbent through a cost-effective and eco-friendly method. Bio synthesis is widely applied for the synthesis of nano materials . Various techniques such as XRD, FTIR, SEM EDX ,TEM and UV–VIS spectroscopy have been used to characterize the nanometal oxide. The obtained nano manganese oxide rods have very good adsorption efficiency due to the presence of some functionalities associated with the oxide material.

In view of growing environmental issues there is a requirement for the immediate eradication of pesticides and its residues from local and commercial streamlets. Quinalphos is one of the most common organophosphorous pesticide especially used in agricultural fields bring about a great impact in environment thereby affecting the health of aquatic organisms and humans. Among the various type of method that has been implemented, photocatalytic reaction is considered as the most relevant technique for the removal of toxic organic contaminants. In this study, modified TiO2 has been synthesized by doping with Fe, S using a simple one-step sol-gel method. The incorporation of Fe3+ and the distribution of S nonmetal in TiO2 crystal lattice were affirmed by the XRD, SEM and FT-IR analysis. The band gap energy of Fe/S/TiO2 nanocomposite has been narrowed to 2.5eV and its photocatalytic activity was extended to the visible region. Thus Fe/S/TiO2 photocatalyst was employed for the eradication of Quinalphos and the complete mineralization was achieved in 12 min of visible light irradiation and it is analyzed by TOC analysis. Furthermore, the reusable feature of the catalyst was demonstrated to be utilised for twelve cycles. The penetration of pesticide residues on protein pockets of fishes was predicted by molecular docking. Furthermore, the reduction in toxicity level of the effluent was examined by using aquatic organisms. Thus Fe/S/TiO2 nanocomposite is an efficient photocatalyst to oxidize emerging organic contaminants due to its high synergetic effect of visible light absorbing tendency and low recombination effect of charge carriers.

ZnO nanoparticles can be used as a photocatalyst in waste treatment because they have good photodegradation. Synthesis of ZnO nanoparticles using green synthesis method from pineapple peel extract, whose results were characterized by XRD (Xray Diffraction), FTIR (Fourier Transform Infra-red), FESEM (Field Emission-Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), Raman spectroscopy, photoluminescence, and a photocatalytic activity assay. This research showed that ZnO nanoparticles had wurtzite phase, alcohol functional groups, and phenol O-H, C=C alkenes, C-O, C-N, and Zn-O. ZnO nanoparticles had a particle size of 20.04 nm, a spherical shape, and a band gap energy of 3.28 eV. The Raman active mode E2(High) at 439.05 cm-1 confirmed the formation of pure phase wurtzite. Photoluminescence results indicated that two emission peaks at 392.07 nm and 595.07 nm were associated with defects such as oxygen and zinc vacancies. The results of the photocatalytic effectiveness test showed the highest percent degradation value of 99.86% at 180 minutes using UV light.