Analytical Methods in Environmental Chemistry Journal
Volume:8 Issue: 1, Mar 2025

Adsorption on biomass has gained popularity recently as a method for reducing pollutants in wastewater before release. This work investigates the adsorption of malachite green (MG) onto sugarcane bagasse (SCB).  To optimize the process, the mass of the bio-adsorbent, contact time, temperature, and pH of the MG solution were investigated with the adsorbate and the adsorbent. The observed results indicate that MG adsorption on SCB is more effective in the environment because of the electrostatic interactions between the organic cations of the dye and the negatively charged SCB surface in this pH range. In ideal circumstances, SCB removes 97% of MG. The adsorption of MG on SCB is better described by the pseudo-second-order model, according to adsorption kinetics modeling. UV-Vis spectrophotometers were used to analyze the fluids under study and determine the dye concentration. Malachite green has a limit of quantification (LOQ) of 0.1 mg L-1 and a limit of detection (LOD) of 0.06 mg L-1 using UV-Vis spectrophotometry. The measuring range of the procedure is 0.1 to 30 mg L-1, which guarantees precise and repeatable results. According to adsorption isotherm modeling, the Freundlich and Langmuir models best describe MG's adsorption on SCB. Given that both the Freundlich parameter 1/n and the Langmuir separation coefficient RL are smaller than 1, it is clear that MG's bio-adsorption on SCB is beneficial. The study's findings demonstrate that SCB, an underutilized agricultural waste, is a reasonably priced bio-adsorbent with a substantial capability for treating wastewater that contains dyes.

Water pollution poses significant threats to the environment and human health, applications of photodegradation technology offer a promising solution for mitigating these impacts by utilizing light energy to break pollutants; this technology can effectively clean contaminated water, contributing to a sustainable challenge and enhanced the practicality and efficiency of photodegradation systems. This study compares the photodegradation efficiency of (20 ppm, pH = 6.4) methylene blue dye (MB) under three different types of ultraviolet (UV) irradiation light sources, which are UV type A (365 nm), UV type B (311 nm), UV type C (254 nm) by using new home-made photoreactor. The photodegradation activity of this system comprises various conditions, first on circulation of MB dye in the system without irradiation or adding catalytic, when irradiation MB dye with UV-A, UV-B, and UV-C light sources with circulation, finally, the effect of adding (0.05) gm of green synthesis of titanium dioxide nanoparticles (TiO2NPs) by using watermelon rind extract with irradiation in the system. Different percentage of MB dye removal was reported. The prepared catalytic TiO2NPs were characterized using ultraviolet−visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive analysis (EDX), X-ray spectroscopy (XRD), and atomic force microscopy (AFM). High photodegradation performance was reported under UV-C and UV-B irradiation of MB dye in 90 minutes.

Electrocatalytic Carbon dioxide (CO2) reduction to carbon products on SnO2-doped ethyl cellulose (EC) was prepared by dispersion of nano-sized tin oxide (SnO2, 25 nm) in ethyl cellulose through sonication by an ultrasonic probe (600 W) for 60 min. The SnO2-EC catalyst is characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The electrocatalytic performance for CO2 reduction was investigated by loading SnO2-EC paste on a 306S.S. rotated disc. The CO2 electroreduction occurred in an H-type cell with three electrodes in 0.1M KHCO3 saturated with CO2 at different potential ranges of -1.0 V to -1.8V vs. RHE for 3 hours. The oxygen content of liquid products was collected and determined using a chemical oxygen demand (COD,15–300 mg L-1) kit, which was quantified by a colorimeter. A higher oxygen content concentration was obtained at -1.2V vs. RHE (-2 mA cm-2) and found to be 235 mg L-1, while the oxygen content tends to decrease with a more negative applied potential of -1.4V, -1.6V, and 1.8V vs. RHE with current densities of -2.5 mA cm-2, -7.3 mA cm-2, and -15.6 mA cm-2, respectively.

The effectiveness and characterization of blended composite materials made of modified biomaterials and iron (III) sulfate coagulant to remove selected dissolved heavy metals from water-chosen samples were examined during the rainy and dry seasons by inductively coupled plasma optical emission spectroscopy (ICP-OES). Water samples were mechanically batch agitated at their prevailing pHs with optimal composite doses. Following the treatment during the rainy season, the results indicated a percent elimination range of 62.16-99.19 percent. Cu > Zn > Pb > Cd; Zn > Cu > Pb > Cd; Pb > Cu > Cd > Zn; and Zn > Cu > Cd > Pb were the percent removal trends in the FBW, ABW, EBRW, and ERWA samples, respectively. During the dry season, a removal range of 93.70 – 100 percent was recorded with the following trend: Pb = Zn = Cu; Zn Pb; and Pb = Cu. Concentrations of all residual metals except Cd satisfied the World Health Organization and Nigerian Standard Organization permissible levels. Interactions of the variables at (p<0.05, p<0.01, and p<0.001) indicated a statistically significant difference. The reduced linear model of analysis of variance (ANOVA) and response surface methodology employed to predict the responses of main and interaction effects of variables for the dosage optimization of composite materials indicated suitability and statistical significance.

This study aimed to evaluate in vitro the influence of extraction methods (maceration and soxhlet) and solvents (hexane, dichloromethane, ethyl acetate and methanol) on the phenolic composition and antioxidant activity of tree citrus species: C. limon, C. limetta and C. aurantifolia. The results showed that the soxhlet remains the best extraction method for quantifying polyphenols, flavonoids and condensed tannins. Polar solvents (ethyl acetate and methanol) make it possible to obtain the best extraction yields and high polyphenols and flavonoids. Citrus aurantifolia shows the highest contents for epicarps and pulps, respectively in polyphenols (326.73mg and 443.57mg EAG g-1 of FW) and in flavonoids (133.00 mg and 138.62 mg EQ g-1 of FW). The evaluation of the antioxidant activity using the 2.2-diphenyl-1-picrylhydrazyl (DPPH) for the different extracts showed that methanol and ethyl acetate extracts by soxhlet possess the best antioxidant activities. A strong antiradical power was noted for the epicarps and the pulps of C. aurantifolia fruit, respectively of 5.13 and 4.89 µg/ml. 15 phenolic compounds were tentatively identified by ultra-high-performance-liquid-chromatographic-diode array (UHPLC-DAD) in the polar Citrus pulp and epicarp extracts. In fact, the identification of three flavonols (rutin, kaempherol and quercetin), two flavanones (hesperidin and naringin), a flavone (3',4',5,7-tetrahydroxyflavone) and a phenolic acid (pyrogallic acid) were the major compounds identified in polar citrus pulp and epicarp extracts.

This research focuses on using the Fenton process and adsorption to treat cationic Acridine Orange dye in aqueous solutions. In the Fenton method the effects of dye concentration, H2O2/ Fe2+ ratio, pH, and reaction time are considered for the optimization of the oxidative process. The experimental results are reported in terms of the removal percentage of AO dye. The optimal reaction conditions to degrade dye from aqueous solutions were: pH 4; 1.0 mM Fe2+ and 1.0 mM H2O2. On the other hand, four more robust epoxy resins, denoted E1 through E4, were synthesized using 4-aminopyridine, 3,3-diaminobenzidine (EDAB), 4-aminobenzoyl hydrazine and polyamine, and characterized using thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). These epoxy resins proved to be effective for the removal of AO dye from an aqueous solution at pH 10 where their adsorption behavior was in keeping with Langmuir’s adsorption model. Comparison between the adsorption and photo-Fenton oxidation process for Acridine Orange (AO) was carried out under different application conditions. Epoxy resins exhibited the maximum adsorption capacity with 980.39, 1515.2, 1694.9, and 1851.9 mg.g-1 for E1-E4 respectively at 25 °C after 1.0 h of shaking time while 81.87% of AO was completely degraded after 10 min of photo-Fenton process.

This work includes the synthesis and characterization of a charge transfer complex from Schiff base-minoxidil with a new azo reagent, 1-(4-hydroxy-3-(4-nitrophenyl diazenyl) phenyl) ethan-1-one, and the determination of minoxidil drug in pharmaceuticals. The charge transfer complex gives a red-colored product that gives its highest absorption at the wavelength of 505 nm. UV-visible, FT-IR, and GC-mass characterized azo reagent, Schiff base-drug, and charge transfer complex. The nature of the complex was determined by studying the Job method and the molar ratio method, which showed that the acceptor-to-donor ratio was (1:1). Simple, easy, highly sensitive, and inexpensive spectrophotometric methods for the determination of minoxidil have been developed. Optimal conditions were studied, which gave good sensitivity. It displayed a linear range of 1–12.5 μg mL-1 and a correlation value of 0.9979. The Sandel sensitivity, the detection limit (LOD), and the quantitative limit (LOQ) were obtained at 0.0110 μg/cm², 0.1019 μg mL-1, and 0.3089 μg mL-1, respectively. The average recovery (%) was 102.47.

The United States Environmental Protection Agency (USEPA) classified benzene, toluene, ethylbenzene, and xylene (BTEX) as a hazardous air pollutant (HAPs). This study aimed to investigate the spatiotemporal variations of BTEX and its health risks in the ambient air of Kerman, Iran. Sampling was actively done using the NIOSH-1501 standard method in 2022. BTEX compounds were analyzed in the laboratory using a gas chromatography flame ionization detector (GC-FID). The effect of BTEX on tropospheric ozone production has been investigated through the calculation of the ozone formation potential (OFP). The average BTEX concentrations during winter and summer were analyzed using GC-FID, resulting in the following order: xylene > toluene > benzene > ethylbenzene. The average total concentration of benzene, toluene, ethylbenzene, and xylene compounds was 29.87, 103.34, 16.89, and 109.44 µg m-3, respectively. In general, the concentration of BTEX in winter was higher than in summer. Due to the average OFP, total BTEX compounds were obtained to be 908.80 µg m-3  and 376.48 µg m-3 in winter and summer, respectively. The non-cancer risk was at a safe level of less than one (HQ<1) in both seasons. The carcinogenicity of benzene in summer and winter was found to be 7.55×10-5 and 1.76×10-4, which is more than the recommended limit of EPA.  Motor vehicles were Kerman's main potential sources of BTEX  in the study period.  Based on the results, it can be concluded that motor vehicles were the main potential sources of BTEX in Kerman during the study period. Therefore, based on the BTEX analysis, gasoline control, green space development, and public transportation can be suggested to diminish the number of BTEXs in Kerman City.