Analytical Methods in Environmental Chemistry Journal

Surface-engineered TiO2 nanoparticles incorporated Chitosan polymer membrane for seawater desalination: Fabrication, characterization, and performance evaluation

Muhammad Nurdin, Corresponding Author, — 2023-12-28

The effect of surface coating against RO membrane over TiO₂-NPs incorporated with chitosan (TiO₂-NPs/chitosan) membrane was evaluated to obtain a simple method to fabricate RO membrane 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 also 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. Under the RO desalination process, the high performance of fabricated membranes was evaluated against water flux and salt rejection. Adding TiO₂-NPs can affect the decrease in water flux value by 23 L m^-2h^-1 and increase salt rejection by 52.94%.

Rapid extraction and separation of mercury in water and food samples based on micelles and azo-thiazoles complexation before determination by UV-Vis spectrophotometer

Hesham H. El-Feky, Corresponding Author, — 2023-12-28

A simple and sensitive procedure has been established 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 λ_max 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 investigated, and a statistical 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 digested before complexation with the azo-thiazoles material at optimized pH before determination by UV-Vis spectrometer.

Removal and determination of carbon monoxide based on copper oxide immobilized on Zeolite 13X Nanocatalyst by catalytic oxidation process and gas flow analyzer

Bahar Parsazadeh — 2023-12-28

Carbon monoxide is one of the main air pollutants, mainly produced from the incomplete combustion of fossil fuels. This study aims to oxidize carbon monoxide by copper oxide nanoparticles immobilized on zeolite13X substrate. The present study 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 nanocatalyst. The design of the experiment and the determination of the number of experiments were analyzed by the central composite design method and the statistical test of analysis of variance by the response surface method and using Design Expert11 software. Also, the structural and morphological characteristics of the nanocatalyst were investigated using BET, BJH, FE-SEM, EDX, and XRF tests. The results show that CuO/Zeolite 13X nanocatalyst efficiently oxidizes carbon monoxide. The highest 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 test results, copper oxide nanoparticles with a weight percentage of 5.9% were loaded on the Zeolite 13X substrate. The reduced Cubic model has an R² of 0.98.

Design and construction of pilot sludge drying package for the excess sludge in petrochemical industries: Heavy metals determination in sludge by polarography and atomic absorption spectrometry

Mostafa Hassani, Corresponding Author, — 2023-12-30

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 steel. 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 wastewater treatment. The heavy metal was analyzed using polarography and atomic absorption spectrometry (AAS). For the validation process, 10 mL of 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 wastewater (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.

Removal of polypropylene nanoplastics from aqueous solution by biochar derived from Date palm fibers: Kinetics and isotherms studies

Mohammad Reza Rezaei Kahkha, Corresponding Author, — 2023-12-30

In this work, activated carbon (AC) derived from powder of date palm fibers (DPF) was examined as an adsorbent for removing polypropylene nanoplastics (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 studies are performed to understand adsorption mechanisms. In the batch system, 30 mL of polypropylene suspension (5-40 mgL^-1) was added to Erlenmeyer flask. First, different amounts of AC adsorbent were added to the container, then microplastic was added to the reactor. The mixture was shaken on a shaker for four hours at 25^oC. The flask was removed from the shaker, and the concentration of PPNPs in the supernatant was measured, and a settling time was obtained for 30 min. A control suspension system without PPNPs nanoplastics (with biochar and without PPNPs) was also performed to evaluate carbon particle interference by turbidity measurements. Our results showed that kinetic data were consistent with the pseudo-second-order kinetic model. Equilibrium data for the adsorption of PPNPs on biochar represented by the Langmuir model is better than the Freundlich isotherm .