Cempedak durian as a potential biosorbent for the removal of Brilliant Green dye from aqueous solution: equilibrium, thermodynamics and kinetics studies

Isothermal and Kinetic Investigation of Exploring the Potential of Citric Acid-Treated Trapa natans and Citrullus lanatus Peels for Biosorptive Removal of Brilliant Green Dye from Water

Trapa natans peels (TNPs) and Citrullus lanatus peels (CLPs) were utilized for the biosorptive removal of brilliant green dye (BGD), after modifying with citric acid. Characterization and surface morphology were studied by Fourier transform infrared spectroscopy and scanning electron microscopy. For the removal of BGD by citric acid-treated Trapa natans peels (CA-TNPs), the optimum conditions were obtained with adsorbent dose 0.8 g, contact time 25 minutes, initial pH 5, temperature 30°C, and agitation speed 100 rpm, while for the citric acid-treated Citrullus lanatus peels (CA-CLPs), adsorbent dose 0.8 g, contact time 20 minutes, pH 5, temperature 30°C, and agitation speed 100 rpm gave optimum results. The qmax values obtained were 108.6, 128, 144.9, and 188.68 mg/g for R-TNP, CA-TNP, R-CLP, and CA-CLP, respectively, while the correlation coefficient (R2) values obtained were 0.985, 0.986, 0.985, and 0.998 for R-TNP, CA-TNP, R-CLP, and CA-CLP, respectively. These favor the Langmuir isotherm and pseudo-second-order kinetics, with negative (ΔG0) values of all adsorbents, determining that the adsorption phenomenon is exothermic and spontaneous in nature. Both citric acid-treated peels of Trapa natans and Citrullus lanatus were found suitable for bulk-scale eradication of hazardous, toxic, and carcinogenic basic cationic dyes.

Mechanistic insights into the adsorption of methylene blue by particulate durian peel waste in water

This study aims to investigate the adsorption of methylene blue (MB) over particulate durian peel waste, which is chemically activated with hydrogen peroxide. The equilibrium data are well described by the Freundlich isotherm model, which indicates that the MB adsorption takes place predominantly on multilayers and heterogeneous surfaces of the biosorbent. The Freundlich adsorption constants, K_F and n, are 11.06 L/g and 2.94, respectively. Thermodynamic data suggest that the MB adsorption occurs spontaneously and endothermically. The enthalpy and entropy for the MB adsorption are obtained as 10.26 kJ/mol and 0.058 kJ/mol K, respectively, in the temperature range of 303-323 K. Based on the stepwise desorption method, the adsorption of MB is dominated by physical interactions, particularly hydrogen bonding.

Disassembly of lignocellulose into cellulose, hemicellulose, and lignin for preparation of porous carbon materials with enhanced performances

Lignocellulose is the primary component of many biomasses, including corn straw. Herein, lignocellulose in corn straw was disassembled into the individual polymers, cellulose, hemicellulose, and lignin via a mild and facile method. Subsequently, three porous carbon materials were prepared by carbonization and chemical activation of cellulose (PCCC), hemicellulose (PCHC), and lignin (PCLC). The three materials showed higher specific surface areas (2565.7, 2996.1, and 2590.3 m² g^-1) and higher porosities (1.4261, 1.5876, and 1.2406 cm³ g^-1) than that of PCCS, a porous carbon material derived from raw corn straw (1993 m² g^-1 and 1.19 cm³ g^-1). Of note, PCCC and PCHC exhibited higher adsorption (1025.5 and 950.1 mg g^-1) of brilliant green (BG), than PCCS (876.7 mg g^-1). Besides, the BG adsorption capacities of the designed materials were higher than that of most adsorbents, and 2-2.5 times higher than that of graphite oxide (416.7 mg g^-1). These study results indicate that the disassembly of lignocellulosic biomass into cellulose, hemicellulose, and lignin is an effective strategy for preparing various porous carbon materials with enhanced performances.

Removal of bromophenol blue anionic dye from water using a modified exuviae of Hermetia illucens larvae as biosorbent

Organic dyes originating from liquid effluents from the textile industries are harmful to the environment. They are toxic and reduce the penetration of light into aquatic environments. In this study, a biosorbent was produced from the exuviae of Hermetia illucens (Linnaeus) larvae and used to remove organic anionic dyes from an aqueous medium. The solids were characterized in terms of thermal stability, chemical structure, morphology, and porosity using thermogravimetric (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N₂ adsorption-desorption. There were studied the effects of pH and dosage of the adsorbent on the adsorption of the bromophenol blue dye, used as a model molecule. The adsorption kinetics was studied with Lagergren's pseudo-first-order rate model. The maximum adsorbed amount was 571 mg g^-1 according to Langmuir's model. The adsorption process was evaluated as exothermic and spontaneous and was classified as physical adsorption. The prepared biosorbent was tested in five consecutive adsorption cycles achieving 99% dye removal at each stage. This demonstrated the maintenance of adsorption efficiency and desorption capacity. These results suggest that prepared biosorbent have potential applications in the treatment of effluents from textile industries.

Brilliant Green and Acid Orange 74 Dyes Removal from Water by Pinus roxburghii Leaves in Naturally Benign Way: An Application of Green Chemistry

The purpose of this study was to use low cost and easily accessible biosorbent for batch-scale elimination of brilliant green and acid orange 74 dyes from aqueous solution. Pinus roxburghii leaves were utilized to study their dye-eliminating capacities. The adsorbent was characterized by FTIR, TGA, DTA, and SEM. The optimized conditions for brilliant green and acid orange 74 dye elimination were adsorbent dose, 1.2 and 1.8 g; contact time, 30 and 45 min; pH, 2 and 1; temperature, 50°C and 60°C; and agitation speed, 125 rpm and 50 rpm for BG and AO-74, respectively. Adsorption records well fitted Langmuir isotherm. Possibility of the procedure was shown by negative values of the thermodynamic parameter ∆G° for both dyes. Kinetic studies showed that adsorption of BG and AO-74 dyes from watery solution by PR leaves followed pseudo-second-order kinetics.

Simultaneous determination of binary solution of triphenylmethane dyes in complex matrices onto magnetic amino-rich SWCNT using second-order calibration method

This study suggested a new method for simultaneous quantification of two dyes in complex matrices using second-order data by spectrophotometry. Second-order data was generated simply without any expensive instrument using two independent variables including wavelength and the monotonic addition of sodium dodecyl sulfate. Solid-phase extraction (SPE) based on amino-rich magnetic single-walled carbon nanotube as an adsorbent was employed prior to second-order data generation. SPE optimization was performed by Box-Behnken design, and parameters and their interaction which were dependent on the simultaneous extraction of dyes were examined. Competitive Langmuir and Freundlich isotherms for a binary system and individual dyes could all represent the equilibrium data well. The second-order data was processed by parallel factor analysis (PARAFAC and PARAFAC2) and multivariate curve resolution-alternating least squares (MCR-ALS). Figures of merit of the model including a limit of detection of 3.0 and 2.5 ng mL^-1 for crystal violet and malachite green, respectively, were estimated using the MCR-ALS method. The combination of the second-order calibration and SPE presents an easy and versatile method for determination of the mixture of two dyes in the presence of uncalibrated interferences in environmental water, synthetic, and fish samples with the recoveries of 94-104.

Application of ZnO nanorods loaded on activated carbon for ultrasonic assisted dyes removal: Experimental design and derivative spectrophotometry method

A method based on application of ZnO nanorods loaded on activated carbon (ZnO-NRs-AC) for adsorption of Bromocresol Green (BCG) and Eosin Y (EY) accelerated by ultrasound was described. The present material was synthesized under ultrasound assisted wet-chemical method and subsequently was characterized by FE-SEM, TEM, BET and XRD analysis. The extent of contribution of conventional variables like pH (2.0-10.0), BCG concentration (4-20mgL(-1)), EY concentration (3-23mgL(-1)), adsorbent dosage (0.01-0.03g), sonication time (1-5min) and centrifuge time (2-6min) as main and interaction part were investigated by central composite design under response surface methodology. Analysis of variance (ANOVA) was adapted to experimental data and guide the best operational conditions mass by set at 6.0, 9mgL(-1), 10mgL(-1), 0.02g, 4 and 4min for pH, BCG concentration, EY concentration, adsorbent dosage, sonication and centrifuge time, respectively. At these specified conditions dye adsorption efficiency was higher than 99.5%. The suitability and well prediction of optimum point was tested by conducting five experiments and respective results revel that RSD% was lower than 3% and high quality of fitting was confirmed by t-test. The experimental data were best fitted in Langmuir isotherm equation and the removal followed pseudo second order kinetics. The experimentally obtained maximum adsorption capacities were estimated as 57.80 and 61.73mgg(-1) of ZnO-NRs-AC for BCG and EY respectively from binary dye solutions. The mechanism of removal was explained by boundary layer diffusion via intraparticle diffusion.