Analytical Methods in Environmental Chemistry Journal
Volume:6 Issue: 4, Dec 2023

The effect of surface coating over titanium dioxide nanoparticles (TiO2-NPs) incorporated with chitosan (TiO2-NPs/chitosan) was evaluated as a reverse osmosis membrane (RO) for enhanced performance on seawater desalination. The impact of surface coating on the chitosan membrane performance in seawater reverse osmosis (SWRO) was investigated by altering the mass of TiO2-NPs (0.25 g and 0.5 g) used for the surface coating RO membrane. TiO2-NPs were applied to the membranes using a surface coating technique and dried to create a sturdy polymer structure. The characteristic of fabricated membranes shows the function group reflects on organic compounds from /chitosan membranes polymer (–OH, -CH, C=O, C-O-C, -CH3, C-O, and NH2). In addition, TiO2-NPs are expressed in the wavenumber range of 850-500 cm-1, which characterizes the presence of Ti-O-Ti bonds. Morphological and crystal analyses of TiO2-NPs incorporated in chitosan membrane show significantly smaller pores formed because TiO2-NPs are essential in the high permeability performance under the amorphous phase structure. Also, the high performance of fabricated membranes was evaluated against water flux and salt. Adding TiO2-NPs can decrease the water flux value by 23 L m-2 h-1 and increase salt rejection by 52.94%. In optimized pH, the seawater desalination had efficient recovery.

A simple and sensitive procedure has been es tablished for analyzing mercury (II) ions spectrophotometrically in the presence of micellar medium using three azo-thiazoles complexing reagents: 2-amino-6-(thiazole-2-yldiazenyl)-3-pyridinol (C8H7N5OS), 8-hydroxy-7-(thiazole-2-yldiazenyl) quinoline-5-sulfonic acid (C12H8N4O4S2), and 1-hydroxy-4-(thiazole-2-yldiazenyl)-2-naphthoic acid (C14H9N3O3S). H1 NMR spectra validated the three azo thiazoles synthesized material. Tween 80 (polysorbate 80) and cetyltrimethylammonium bromide (C19H42BrN as molecular biology) are micellar mediums to enhance sensitivity. Absorbances were measured for Hg (II) complexation with R1, R2, and R3 at λmax of 617, 633, and 554 nm, respectively. The UV-Vis spectrophotometer showed calibration curves in the 0.2-15 mg L-1. The molar absorptivity, Sandell’s sensitivity, detection, and quantification limits (LOD, LOQ) were determined. The interferences of various ions were inves tigated, and a s tatis tical assessment of the results was performed. The methods have been applied for trace determination of mercury (II) in food and environmental water samples. For food samples, all samples were diges ted before complexation with the azo-thiazoles material at optimized pH before determination by UV-Vis spectrophotometry.

Carbon monoxide is one of the main air pollutants, mainly produced from the incomplete combus tion of fossil fuels. This s tudy aims to oxidize carbon monoxide by copper oxide nanoparticles immobilized on zeolite13X subs trate. The present inves tigation was conducted to determine the effect of carbon monoxide concentration parameters (in the range of 200-1400 ppm) and reaction temperature (in the range of 100-500 °C) on the efficiency of carbon monoxide conversion by CuO/Zeolite 13X nanocatalys t. The design of the experiment and the determination of the number of experiments were analyzed using the central composite design method, and the s tatis tical tes t of analysis of variance was done using the response surface method. Also, the s tructural and morphological characteris tics of the nanocatalys t were inves tigated using BET, BJH, FE-SEM, EDX, and XRF tes ts. The results show that CuO/Zeolite 13X nanocatalys t efficiently oxidizes carbon monoxide. The highes t conversion efficiency of 82.6% was obtained at a temperature of 400 °C and a carbon monoxide concentration of 500 ppm as the optimal conditions. According to the EDX tes t results, copper oxide nanoparticles with a weight percentage of 5.9% were loaded on the Zeolite 13X subs trate. Design Expert11 software reduced the cubic model with an R2 coefficient of 0.98.

In this research, according to the high amount of sludge in a petrochemical company, an iron package type of drying sludge bed was made/designed with carbon s teel. Then, the drying sludge pond was filled with layers of sand with different mesh sizes. The excess sludge from the sedimentation pond was passed over this bed, and the amount of sludge removed by the bed was obtained at %96. The values of heavy metal and microbial forms were determined using the proposed method based on activated sludge after was tewater treatment. For the validation process, 10 mL of deionized water (DW) was mixed with 1.0 g of dried sludge with pure nitric acid (2% HNO3), and then the solid phase was filtered with the Whatman filter (WF). The concentration of heavy metals (As, Cd, Cu, Pb, Hg, Mo, Ni, Co, Se, Zn) in the remaining solution of sludge (mg kg-1) and was tewater (μg L-1) was extracted/ separated based on sulfur-doped graphene oxide adsorbent (SDGO) by solid-phase microextraction procedure (SPME) before being determined by the flame and hydride generation atomic absorption spectrometry (F-AAS; HG-AAS) which had similar range to the polarography analysis. The limit of detection (LOD), linear range (LR) and preconcentration factor (PF) for (As, Hg) and (Cd, Cu, Pb, Mo, Ni, Co, Se, Zn) were obtained (0.016 μg L-1;3.3μg L-1), (0.05-10 μg L-1; 10-1000 μg L-1), and 10.0 by HG-AAS and F-AAS, respectively.

In this work, activated carbon (AC) derived from powder of date palm fibers (DPF) was examined as an adsorbent for removing polypropylene nanoplas tics (PPNPs) from aqueous solutions. The adsorbent was characterized using XRD, FT-IR, and SEM analyses. Affecting parameters on removal efficiency in a batch reactor, such as contact time, concentration of PPNPs and amount of adsorbent, were evaluated and optimized. Equilibrium and kinetic s tudies are performed to unders tand adsorption mechanisms. In the batch sys tem, 30 mL of polypropylene suspension (5-40 mgL-1) was added to Erlenmeyer flask. Firs t, different amounts of AC adsorbent were added to the container, then microplas tic was added to the reactor. The mixture was shaken on a shaker for four hours at 25oC. The flask was removed from the shaker, the concentration of PPNPs in the supernatant was measured, and a settling time of 30 min was obtained. A control suspension sys tem without PPNPs nanoplas tics (with biochar and without PPNPs) was also performed to evaluate carbon particle interference by turbidity measurements. Our results showed that kinetic data were consis tent with the pseudo-second-order kinetic model. Equilibrium data for the adsorption of PPNPs on biochar represented by the Langmuir isotherm model is better than the Freundlich isotherm model.

In this s tudy, manganese (Mn II) was determined in aqueous media by an electrochemical method, and its removal was evaluated using the aeration-filtration process (AFP). An electrochemical sensor based on carbon pas te (EPC) modified with the 5-Br-PADAP ligand was used to measure Mn (II) in aqueous media. Through the optimization of analytical parameters in cathodic s tripping voltammetry (CSV), real boreholes and well water samples could be analyzed for manganese content. The optimum parameters such as preconcentration potential (1100 mV), preconcentration time (240s), 5-Br-PADAP ligand concentration (20 μmol L-1), and electrode rotation speed during pre-concentration (1000 rpm) were s tudied and optimized. The detection limit (LOD) is es timated at 3 ×10-7 mol L-1 with a relative s tandard deviation (RSD) of 3.36%. The real samples showed that some water points have more concentration than the s tandard. A simple, effective, inexpensive, and rural-friendly method was used for treating manganese-rich water. Following the aeration phase, the sand and gravel column was filtered toremove manganese (II) from the water. The removal efficiency of Mn was obtained at a rate of 74.8- 84.5% and more than 95% after two hours of aeration and 1 hour at pH 8 for real samples.

This s tudy developed an applied method based on the degradation to remove ethylene bisdithiocarbamate (EBDC) fungicides from was tewater and agricultural runoff by zinc oxide nanoparticles (ZnONPs). The synthesized ZnONPs were characterized using XRD for material crys tallinity, scanning electron microscope (SEM) and particle size analysis (PSA) for surface s tructure, morphology and particle size (nm), respectively. The energy-dispersive X-ray spectroscopy (EDX) spectra confirmed the presence of zinc and showed that the synthesized zinc oxide nanoparticles were pure. Determination of the adsorption and photocatalytic degradation of Mancozeb (MCZ) fungicides based on ZnONPs was performed. Different amounts of ZnONPs were loaded into an MCZ fungicide solution in different concentrations. High-performance liquid chromatography (HPLC) and UV-Vis spectroscopy were used to determine the dithiocarbamate residue and the degradation efficiency of the synthesized particles. The particle size dis tribution of the synthesized ZnONPs was found to be in the range of 50-95 nm. At optimum conditions, with a ZnONPs dosage of 10 mg, (MCZ) fungicide concentration of 9.37 mg L-1, and a duration of 60 minutes, the degradation efficiency was surpassed at more than 95%. Additionally, the nanoparticles demons trated excellent reusability and maintained efficient activity for up to three cycles. It is crucial and significant to keep on exploring the intrinsic capabilities of abundant metal oxides like zinc oxide nanoparticles for environmental remediation and other applications.