Search

This study focuses on the synthesis of a novel Cerium-Magnesium (CeO2-MgO) binary oxide nanomaterials by a simple co-precipitation process and used to remove harmful pollutants such as Cr(VI), Cu(II), and F. The morphology, phase, crystallite size, thermal stability, functional groups, surface area, and porosity of the synthesized nanomaterial were determined by using XRD, SEM, FTIR, TGA/DTA, and BET studies. The prepared nanomaterials showed adsorption selectivity of Cu(II) ≈ F−> Cr(VI) with a high adsorption capacity of 84.3 − 133.3 mg/g for Cu(II), Cr(VI), and F−. The distribution coefficient (Kd) for F− and Cu(II) was found to be in the range of 104 mL/g which was adequate. The adsorption isotherms for Cr(VI), Cu(II), and F− followed the Freundlich isotherm model and the pseudo-second-order kinetic model in linear and nonlinear forms, indicated multilayer adsorption. Maximum removal of Cr(VI), Cu(II), and F− ions was found to be 92.84%, 98.88%, and 95%, respectively, for a high initial concentration of 50 mg/l by 2 g/l dosages of prepared CeO2-MgO binary oxide nanomaterials employed as an adsorbent in this study. The results showed that novel CeO2-MgO binary oxide nanomaterials are promising adsorbent for removing hazardous inorganic contaminants from the water due to their adsorption capability and chemical stability. [ABSTRACT FROM AUTHOR]

Industrial dye production chemicals contribute significantly to environmental pollution. This study explores the use of nanotechnology, specifically nano fertilizers and adsorption technology, for efficient removal of synthetic anionic dyes and enhancing agricultural production. Nano adsorbents (MnO, FeO, ZnO, and CuO) were generated using the co-precipitation method. Optimal conditions for Manganese oxide (MnO) were pH 2 (33.2 mg/g), dosage 0.01 g/50 mL, and adsorption capacity 77.2 mg/g. FeO optimal conditions were pH 2 (21.5 mg/g), dosage 0.01 g/50 mL, and qe 40.5 mg/g. CuO optimal conditions were pH 2 (28.2 mg/g), dosage 0.01 g/50 mL, and qe 71.3 mg/g. ZnO optimal conditions were pH 2 (25.4 mg/g), dosage 0.01 g/50 mL, and qe 64.2 mg/g. Pseudo 1st order and Freundlich sorption isotherms were best-fit models. Endothermic reactions were observed, indicating the sorption process's nature and feasibility. Electrolyte concentrations affected the sorption potential. Surfactants/detergents reduced sorption efficiency. 0.5 N NaOH proved most effective for desorption. In column studies, optimal conditions for acidic RB-71 dye sorption were 3 cm bed height, 1.8 mL/min flow rate, and 70 mg/L inlet dye concentration. Metal oxide showed exhibited crystal and polymorphs structure. FT-IR spectra depicted metal-oxide peaks between 400 and 899 cm−1. SEM micrograph reveals a spherical shape with an approximate size of 10–50 μm. The adsorption method's novelty lies in its easy handling, eco-friendliness, and cost-effectiveness, making it a promising technology for practical-scale application in addressing dye pollution. Highlights: Functionalization of the nano-adsorbent with other materials increases their surface area and subsequently, their uptake capacity. ZnO, CuO, MnO and FeO nanoparticles were synthesized using chemical co precipitation method. Efficient removal of anionic dye RB-71 dye. Adsorption process was well fitted to Freundlich isotherm, Pseudo-1st order kinetics and Intraparticle diffusion models. Desorption and reusability studies indicated excellent results and stability. [ABSTRACT FROM AUTHOR]

Environmental pollution with heavy metals is a problem of worldwide importance due to their toxicity and potential health risks. Among the heavy metals found in industrial waters are such toxic metals as Cd(II), Zn(II), and Cr(VI). In this study, the potential of Georgian natural and modified mordenite as a low-cost, eco-friendly adsorbent for the removal of cadmium (II), zinc (II), and chromium (IV) from aqueous solutions is studied. Langmuir and Freundlich isotherms are used to model adsorption data. Studies have shown that the correlation coefficient values (R²) were best fitted by the Langmuir isotherm. The maximum adsorption capacities are 0.84mg/g, 118.92mg/g and 2.25mg/g for cadmium(II), zinc(II) and chromium(IV) respectively as described by Langmuir isotherm. [ABSTRACT FROM AUTHOR]

In the current report, both response surface methodology (RSM) and artificial neural network (ANN) were employed to develop an innovative way for removing crystal violet (CV) from aqueous media using Haloxylon salicornicum (HS) as a cost‐effective, eco‐friendly adsorbent. HS was characterized using scanning electron microscopy (SEM) and Fourier‐transform infrared (FTIR) spectroscopy. The effects of operational parameters such as adsorbent dosage, initial dye concentration, and pH on HS were studied using a central composite design (CCD). A comparative analysis of the model findings and experimental measurements revealed high correlation coefficients (R2ANN = 0.994, R2RSM = 0.971), indicating both models accurately predicted HS. The predictive performance of the ANN and RSM models was evaluated using metrics such as mean absolute deviation (MAD), mean absolute percentage error (MAPE), root mean square error (RMSE), mean square error (MSE), and the correlation coefficient (R2). The results indicate that the ANN model provides greater accuracy compared to the RSM model. The experimental data were analyzed using both linear and nonlinear forms of pseudo‐first and pseudo‐second order kinetic models (LPFO, NLPFO, LPSO, and NLPSO). Statistical error analysis was conducted to identify the best‐fitting kinetic or isotherm models for the adsorption data. The adsorption process of CV/HS was best described by NLPSO and LPSO. Additionally, the adsorption isotherms were analyzed using linear and nonlinear regression methods. The findings indicated that the linear Langmuir and Freundlich isotherms provided a more accurate fit compared to the nonlinear models, demonstrating greater effectiveness in accounting for the adsorption parameters. Thermodynamic investigations clearly demonstrate that the biosorption of CV is spontaneous and exothermic. This cost‐effective adsorbent is highly promising for treating textile wastewater. [ABSTRACT FROM AUTHOR]

Numerous lives around the world are impacted by water pollution. Many effluents and toxins from numerous industries are being released directly into the freshwater bodies causing serious problems to various living creatures in the environment. There are many approaches in practice for water purification, among which are nano-adsorbent technologies that are considered to be sustainable and is the most reliable method. In this study, 3 different types of silver nanoparticles have been synthesized using three plant gums, namely, Moringa oleifera (MO), Azadirachta indica (AI), and Bauhinia purpurea (BP). The green synthesized silver nanoparticles have been characterized using UV Visible Spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-ray Powder Diffraction (XRD), etc. Bioactivity studies like antibacterial activity and antioxidant activity have been observed, and pesticidal activity was also performed by exposing the mealybugs (Phenacoccus solenopsis) to three different silver nanoparticles (concentrations: 10 µg/ml and 20 µg/ml). These silver nanoparticles were subjected to a batch adsorption system for the effective removal of methylene blue (MB), crystal violet (CV), congo red (CR), rifampicin (RF), and chromium (CH). [ABSTRACT FROM AUTHOR]

Water pollution due to waste systems has become a serious environmental issue globally due to industrial development and raise in anthropogenic activities. Recently, researchers have given much more attention on the environmental remediation. In connection with this, agro waste biomass has extensively applied as bio-adsorbent material to eliminate hazardous pollutants. This study analysed potential of Ipomoea pes caprae biomass (raw and sulphuric acid–modified) as bio-adsorbent to eliminate Malachite Green dye from solutions. The newly synthesised bio-adsorbent were examined using SEM, EDX, TGA, XRD and FTIR analytical techniques. Experimental investigations were ascertained to investigate effects of process variable including period of interaction, temperature, preliminary MG dye concentration, pH and biomass dose on the dye removal. Batch experimental results corresponds that 98.5% and 99.02% of MG dye are removed at 30 oC, pH of 8.0, initial MG dye concentration of 0.025 g/L with the concentration of 3.5 g/L and 1.75 g/L for raw and sulphuric acid–treated Ipomoea pes caprae biomass, respectively. The modelling study illustrates Langmuir and pseudo-first-order model which have been well obeyed with isotherm and kinetics, respectively. Monolayer bio-adsorption capacity of raw and sulphuric acid–treated biomass reaches the maximum value of 247.8 and 302.1 mg/g at 303 K. Thus, the sulphuric acid–modified Ipomoea pes caprae biosorbent has higher potential in eliminating dye in remediation processes. [ABSTRACT FROM AUTHOR]

The industry has suffered major chromium wastewater issues. Chromium is a heavy metal that can threaten both nature and people's health. Adsorption is a simple, environmentally friendly, and effective process for removing chromium from wastewater. Iron sand is an alternate adsorbent that can adsorb chromium. The iron sand in this research originated from Sukabumi, Indonesia, with a hematite content of 63.335%. The goal of this study is to evaluate the adsorption mechanism of hematite based on adsorbent weight, Cr(VI) initial concentration, pH of the solution, and contact time. This study was conducted experimentally throughout multiple phases. First, hematite was characterized using XRD, BET, FTIR and XRF to assess crystal structure, mineral composition, surface area, functional groups and the percentage of hematite in iron sand. Subsequently, the pH and contact time were optimized. The highest adsorption capacity is then determined using the Langmuir and Freundlich isotherms. The study found that hematite has a surface area before and after adsorption of 619.486 m²/g and 334.783 m²/g, with XRD peaks at 2θ = 33.037° and 35.357°, Fe-O bonds with a wavelength of 647.17 cm-1 and hematite content of 63.335%. Optimal Cr(VI) adsorption occurs at pH 1, with a contact time of 120 minutes, Cr(VI) concentration of 50 mg/L, 5.0 g mass of hematite, with an adsorption capacity (Qe), and adsorption efficiency (%) of 3.83 mg/g and 75.95%. The Freundlich isotherm model accurately represents adsorption, revealing a heterogeneous surface. The linear equation of the Freundlich curve is Log Qe = 0.1152 Log Ce + 0.6376, R² = 0.9999, with the value of adsorption capacity (kf) = 4.3411 mg/g and adsorption intensity (n) = 8.681. The enthalpy of adsorption (ΔHads) at a concentration of 20 mg/L, 2.5 g, pH 3, and 30 minutes is -95.852 kJ/mol, indicating chemisorption. [ABSTRACT FROM AUTHOR]

This study investigates the potential of 5-amino-1,3-diphenylpyrazole and nitrogen-enriched 5-hydroxy-1,3-diphenylpyrazole to inhibit corrosion of mild steel in acidic environments. A comprehensive approach combining weight loss measurements and Density Functional Theory (DFT) calculations was employed to analyze the inhibitory effect under various concentrations, immersion times, and temperatures. At an optimal concentration of 0.5 mM, 5-amino-1,3-diphenylpyrazole displayed an impressive 94.7% inhibition efficiency, while 5-hydroxy-1,3-diphenylpyrazole achieved 86.4% efficiency at 303 K after 10 hours of exposure. Both compounds exhibited a mixed-type inhibition behavior, with increasing efficiency observed at higher concentrations. DFT calculations provided insights into the interaction between the molecules and the metal surface, along with their electronic properties, aiding in understanding the corrosion inhibition process. The investigation revealed that Langmuir isotherms govern the adsorption mechanism, and the calculated thermodynamic parameters suggest a complex interplay at the metal/solution interface, involving both chemisorption and physisorption. These findings provide valuable knowledge about the mechanisms of corrosion inhibition by these molecules, paving the way for the development of effective strategies to protect mild steel in corrosive environments. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adsorption is a widely used technique for separating impurities in various industries. This method offers flexibility in design and operation and results in the production of high‐quality purified wastewater. This experimental research investigates the effectiveness of carbon‐based adsorbents, such as graphene, graphene oxide and carbon dots, in removing impurities and increasing hydrogen peroxide concentration through adsorption. RESULTS: Various characterization techniques were used to investigate each adsorbent's chemical properties and surface morphology, including Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller analysis. According to adsorption tests under the defined conditions, the synthesized graphene showed the highest efficiency in impurities removal from hydrogen peroxide, with purity level of 45%. Graphene showed higher efficiency than graphene oxide and carbon dot samples, with a purity of 36% and 32%, respectively. Various factors, such as time, temperature and adsorbent dosage, were investigated at different stages of the experiments. The results show that the adsorption of impurities on carbon‐based adsorbents is an exothermic process. CONCLUSION: It was shown that graphene structure results in an adsorption capacity of up to 147.06 mg g−1, which was increased by 45% in comparison to graphene oxide and carbon dot as adsorbents. To gain further insights, isothermal and kinetic experiments on the adsorption of hydrogen peroxide were performed. The results indicate compliance with the Freundlich isotherm, suggesting multilayer adsorption and pseudo‐second‐order kinetics. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: Produced water, a byproduct of oil and gas extraction, often contains elevated levels of heavy metals, including chromium, posing significant environmental and health risks. Cassava stem biochar (CSB) was prepared by pyrolysis of cassava stem and its potential has been investigated for the removal of chromium (Cr) from produced water. Batch adsorption experiments were conducted to evaluate the adsorption capacity of CSB under various conditions of pH, contact time, initial produced water concentration, adsorbent dosage, agitation speed, temperature and particle size. RESULTS: From the experiment results, it was found that CSB showed good adsorption capacity of chromium ions from produced water. The adsorption process was found to be highly pH‐dependent, with maximum removal efficiency observed at a pH of 4.0. Equilibrium data were fitted to the Freundlich isotherm models, indicating multilayer adsorption on a heterogeneous surface. The kinetic data demonstrated that the adsorption process followed pseudo‐first‐order as well as pseudo‐second‐order kinetics, suggesting a physisorption and chemisorption mechanism. The thermodynamic parameters, including changes in enthalpy (ΔH), and entropy (ΔS), were evaluated to gain insights into the spontaneity and feasibility of the adsorption process. The negative ΔH values indicated that the adsorption of Cr onto CSB was non‐spontaneous and exothermic in nature. The negative ΔS value suggested the adsorption is feasible. CONCLUSION: This comprehensive study demonstrates the potential of cassava stem biochar as an effective and environmentally friendly adsorbent for the removal of chromium from produced water. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

It has been previously reported that thiourea modified poly(acrylonitrile-co-acrylic acid) (TMPAA) could successfully be employed as polymeric adsorbent for the sequestration of cationic dyes and nitro-phenol. In this research, parametric optimisation, kinetic and isotherm analyses on the sequestration of diclofenac (DCF) and amoxycillin (AMX)) by TMPAA were investigated for the first time. The central composite design (CCD) results revealed that the optimisation exhibited high significance and reliability. The analysis of variance (ANOVA) indicated that TMPAA dose, antibiotic concentration and adsorption time exhibited high significance effect on the DCF and AMX sequestration. The 3D response surface plots showed notable antagonistic interaction among the adsorption parameters. A maximum DCF uptake of 97.94% was achieved under optimum condition of 0.1 g TMPAA dose, 25 mg/L, and 54 min, while 94.06% AMX removal was obtained at 0.1 g sorbent dosage, 25 mg/L, and 34 min contact time. Predicted and experimental results confirmed the accuracy of the established optimal conditions for both antibiotics. It was discovered by adsorption analysis that the pseudo-second-order kinetic and Redlich-Peterson models agreed with the adsorption kinetic and isotherm data. The findings suggest that the synthesised TMPAA polymer is capable of removing DCF and AMX from aqueous solutions. [ABSTRACT FROM AUTHOR]

The sorbents Ni-Cu-FNP's, Ni-Zn-FNP's, Mn-FNP's, and Zn-FNP's were synthesised and utilised for the removal of Direct Golden Yellow RL dye. The optimum pH for the adsorption of direct golden yellow RL dye was 4, and 3 having the sorption capacities of 32.56, 30.44, 34.39, and 36.91 mgg−1 for Ni-Cu-FNP's, Ni-Zn-FNP's at 45 min and Mn-FNP's, Zn-FNP's at 60 min respectively with the optimum dosage of 0.05 g/50 mL. The maximum sorption capacities were 39.08 (Ni-Cu-FNP's), 35.08 (Ni-Zn-FNP's), 42.93 (Mn-FNP's), and 44.22 mg/g (Zn-FNP's) at 40°C, 37°C, 44°C, and 44°C respectively and the reduction observed in the sorption capacity by raising the temperature, showed that the process is exothermic The optimal initial concentration of dyes for all the sorbents having the maximum sorption capacities of 54.30 mg/g (Ni-Cu-FNP's), 51.25 mg/g (Ni-Zn-FNP's), 63.45 mg/g (Mn-FNP's), and 66.35 mg/g (Zn-FNP's) were 75, 100, 100, and 75 mg/L respectively to get maximal acidic dyes adsorption. Langmuir equilibrium isotherm for sorption showed good fitness on the data obtained by sorption while the pseudo-2nd-order proved good fitness on kinetic data of experiments. Surfactants, detergents, and different molar solutions of electrolytes (NaCl and AlCl3) decreased the sorption capabilities of the sorbents for the selected dye. [ABSTRACT FROM AUTHOR]

The pollution of heavy metals in the environment is a critical problem due to their toxicity. Cr(VI) is a toxic substance of widespread use in many industries and mixing with the environment. Silver nanoparticles (AgNPs) were synthesized using aqueous leaf extracts of Justicia schimperiana and trisodium citrate for Cr(VI) adsorption. The nature of bio- and chemo-synthesized AgNPs were characterized and showed the presence of multiple functional groups namely hydroxyl, carbonyl, nitriles, amines, and amides indicating the surface-bound phenolic groups and proteins from Justicia schimperiana leaf and played a crucial role in the biosynthesis, capping, and stabilizing agent of AgNPs. The X-ray diffraction studies confirmed the face-centered cubic structure and indicated the presence of pure crystalline shapes of AgNPs. The silver nanoparticles-Justicia schimperiana leaf extract (AgNPs-GSLE) had a size range of 34.42–37.85 nm with an average size of 36.81 nm and silver nanoparticles-citrate (AgNPs-citrate) had a size range of 11–16 nm with an average size of 14.00 nm with irregular shape and spherical shape in the sample, respectively, similar to the results obtained from the scanning electron microscope. AgNPs-GSLE and AgNPs-citrate were able to perform the maximum adsorption capacity of 128.70 and 34.38 mg/g for the removal of Cr(VI), respectively. The equilibrium results were fitted better to the Langmuir adsorption isotherm model. Cr(VI) adsorption on AgNPs-GSLE followed pseudo-first-order kinetics while AgNPs-citrate followed pseudo-second-order kinetics. The synthesized nanoparticle using Justicia schimperiana extract is promising for Cr(VI) removal from an aqueous solution with a high surface area and green method. [ABSTRACT FROM AUTHOR]

The amount of carbon dioxide (CO2) in the atmosphere has been increasing; since the industrial revolution, making CO2 emissions is the significant contribution to change the climate. Business cost waste biomass–based adsorbent materials are utilised for the capture of CO2 recent years. In this present study, a hot plate combustion method (HPCM) was used to synthesis porous activated carbon from wild sugarcane. The as-synthesised adsorbents were examined using X-ray dispersive spectroscopy, Fourier transform infrared (FTIR) spectrum, and field-emission scanning electron (FE-SEM) microscopy. Studies on thermodynamics were carried out. Go, Ho, and So were computed, and the process viability was examined. For sugarcane activated carbon, the experimental isotherm results were characterised using Langmuir, Freundlich, D-R, Temkin, and Sips adsorption isotherms. The Langmuir model, with a co-efficient R2 of 0.988 and the adsorption rate is 1.225 × 10−3 mol/g/min, gives the best fit with the adsorption of the CO2 on adsorbent. The activated carbon was found to be effective for CO2 adsorption process and the calculated and experimental qe values are same with R2 value of 0.9888, which demonstrates that the system is governed by pseudo-second-order kinetics. Equilibrium point was attained at 90 min. [ABSTRACT FROM AUTHOR]

The remediation of industrial wastewater to eliminate heavy metal ions represents a pressing environmental requirement. A previously prepared adsorbent, based on chitosan modified with uracil (UCs), was investigated for the first time in this work to eliminate Cu(II) ions. The best conditions for elimination were as follows: adsorbent dose = 0.01 g, Cu(II) ions solution concentration = 0.2 g L−1, pH = 6, and temperature = 25 °C. The adsorption kinetics were favorable for the pseudo second order due to the correlation coefficient's value being the highest (R2 = 1.0). The experimental value of qe (99.65 mg g−1) was comparable to that of the theoretical one (100 mg g−1). The removal efficiency reached 99.65%, and the adsorption isotherm coincided with the Freundlich model, denoting that the nature of its adsorption was multi-layered. Cu(II) ions removal mainly relies on the physisorption phenomenon. The desorption percentages reached 92.65, 75.29, 49.29, and 19.92% after four successive cycles. So, the insertion of nitrogen-rich uracil along the chitosan chains, as binding sites for Cu(II), is deemed to be an outstanding opportunity to produce an appropriate, efficacious adsorbent that is a good choice to apply in the metal removal domains. [ABSTRACT FROM AUTHOR]

AbstractThe study examined the biosorption of Zn+2 by chemically modified Hevea brasiliensis sawdust using a batch adsorption system. The influence of concentration, pH, contact time, and adsorbent dose in a batch biosorption process were analyzed and the maximum Zn+2 uptake capacity was found as 36.8 mg/g. The Langmuir and Temkin model was found to be the most accurate when the experimental data were analyzed using the different adsorption isotherms models. This study presents an experimental modeling approach for the biosorption process based on artificial neural networks (ANN). Data from biosorption experiments were utilized to train and validate the ANN model. The ANN model can effectively represent the biosorption process, as demonstrated by the significant correlation (R2 = 0.998) established between the model and experimental data. A kinetic study revealed that the Zn+2 biosorption was favored by the pseudo-first-order and pseudo-second-order models. The process is feasible, spontaneous, and endothermic, according to thermodynamic study. The H. brasiliensis sawdust underwent chemical carbonization, and its characteristics were examined using energy EDX, BET surface area analyzer, SEM, XRD, and FTIR. [ABSTRACT FROM AUTHOR]

The nickel ferrite nanoparticles (NFO) doped with divalent metal ions (Ni1 − xMxFe2O4, x = 0.0, 0.02, 0.09 and M = Mg2+, Ca2+, Mn2+, Zn2+) were prepared by co-precipitation method and analyzed for their structural, optical, functional group and morphological characterizations. Samples thus prepared were used as a photocatalyst to remove Rhodamine B (RhB) dye from wastewater under sunlight illumination using batch adsorption technique. Doping of NFO led to an increase in dye degradation efficiency. The highest photocatalytic degradation efficiency was obtained for doped NFO NPs (x = 0.02, M = Mn2+) nanoparticles (83%) at a pH of 5, 0.030 g of adsorbent dosage in 5 mg/L of dye solution at room temperature. The validity of adsorption data was estimated using nonlinear models of kinetics (1st and 2nd order) as well as isotherm (Langmuir's model and Freundlich's model). The nonlinear pseudo 1st order kinetic model (Correlation coefficient, R2 = 0.97078) and the Langmuir model (R2 = 0.95659) were found to be more suitable than 2nd order (R2 = 0.96998) and Freundlich model (R2 = 0.91708) for photocatalytic degradation of RhB dye on synthesized samples. The maximum adsorption capacity of RhB dye over synthesized samples is 25.95 mg/g. Sample's stability after photocatalytic degradation of dye is investigated by FTIR and XRD techniques. The prepared sample's antibacterial activity was explored for Escherichia coli (max zone of inhibition (ZOI)-15.30 ± 1.00 mm) and Staphylococcus aureus (ZOI-15.50 ± 1.15 mm) using the well diffusion method. Further, the antifungal activity was assessed against soil-borne fungal phytopathogens such as Rosellinia necatrix (max% inhibition-52.75 ± 1.00%) and Fusarium oxysporum (36.55 ± 0.57%). The obtained results revealed that NFO and doped NFO nanoparticles possess excellent photocatalytic, antibacterial and antifungal properties. These nanoparticles could be easily isolated from the water solution as soon as the disinfection activity is completed using an external magnetic field. [ABSTRACT FROM AUTHOR]

Rice husk is an inexpensive and readily available adsorbent for heavy metal ions, though its natural form lacks sufficient adsorption capacity. This study focuses on improving its ability to adsorb Cr(VI) by treating it with NaOH. After treatment with 1N NaOH at 90 °C for 4 h, the adsorption efficiency of rice husk for Cr(VI) increased by almost 30%. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy revealed an increase in the cellulosic content of the treated rice husk, while X-ray diffraction indicated the formation of new polymorphs and enhanced crystallinity of the cellulose fraction. Among the applied isotherms, the Redlich-Peterson and Langmuir models best described the adsorption, suggesting both monolayer and multilayer adsorption. The maximum monolayer adsorption capacities were determined to be 18.9, 21.1, and 22.9 mg g−1 at 303 K, 313 K, and 323 K, respectively. The kinetic data fit well with pseudo-second-order and Elovich models, confirming the chemical nature of the adsorption process. Activation energy, along with other kinetic and thermodynamic parameters, showed that the process is endothermic, involving both physical and chemical interactions. FT-IR analysis identified various functional groups involved in the chemical interaction with chromium, while XPS confirmed that all adsorbed chromium was in the + 3 oxidation state. The presence of interfering anions reduced the adsorption efficiency of NaOH-treated rice husk for Cr(VI), regardless of the anion type, while regeneration studies showed that the adsorbent could be reused for up to five adsorption–desorption cycles. [ABSTRACT FROM AUTHOR]

Copyright of Afyon Kocatepe University Journal of Science & Engineering / Afyon Kocatepe Üniversitesi Fen Ve Mühendislik Bilimleri Dergisi is the property of Afyon Kocatepe University, Faculty of Science & Literature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of carbon adsorbents in solid phase extraction (SPE) of cadmium in very low concentrations has become very common due to its high efficiency and low price. In this research, carbon spheres (CSs) produced from sucrose were synthesized using the hot oil method and were used as carbon adsorbents in solid phase extraction of cadmium from aqueous solutions. Adsorption isotherm experiments in the concentration range of 5 to 10000 ppb cadmium, kinetics of adsorption in 10 to 140 seconds, pH-dependent adsorption in the range of pH 1 to 10 and the effect of ionic strength and competing cations on the efficiency of cadmium adsorption in concentrations after The field was carried out from 0 to 50 ppm. The efficiency of cadmium washing using HNO3 was done in the concentration and volume range of 0.1 to 0.5 (eqL-1) and 40 to 160 (μl), respectively. CSs had a specific surface area of 375/500 m2g-1 with a completely spherical and smooth shape. The data of isotherm and kinetics of Cd adsorption showed the best fit with Langmuir model and Elovich model, respectively. The maximum cadmium absorption capacity (qm) for CSs was equal to 7.367 mg g-1. Cd absorption efficiency reached the maximum absorption value at pH 10. CSs showed the highest resistance of cadmium absorption efficiency against potassium cation. A normal concentration of 0.5 HNO3 in a volume of 160 microliters was considered for washing Cd from CSs. Therefore, CSs can be a suitable carbon adsorbent for SPE Cadmium from water samples. [ABSTRACT FROM AUTHOR]

In recent years, pollutants released into the environment from various sources threaten environmental health. Rapid industrialization and the constantly increasing needs of people facilitate the release of more hazardous wastes into the ecosystem. The presence of pollutants in water resources causes a wide range of adverse effects. In this study, calcium phosphate nanomaterial (Ca3(PO4)2 NM) was synthesized from biological waste eggshells for the cadmium removal in synthetic domestic wastewater, and a treatment method was developed using these NMs. The Ca3(PO4)2 NMs were produced by using a biowaste which provides the synthesis procedure greener approach. The biogenic NMs were used to remove toxic cadmium ions from wastewater samples. Cytotoxicity and genotoxicity studies of the synthesized NMs were also carried out, and their possible effects on the health of living organisms and the ecology were examined. In the developed method, the parameters affecting the removal of cadmium from wastewater samples were optimized and the removal efficiency was calculated by determining cadmium in a flame atomic absorption spectrophotometer system (FAAS). Synthetic domestic wastewater samples were utilized for evaluating the applicability of the developed treatment strategy. In addition, the adsorption capacity of the material for Cd2+ ion was calculated and the values obtained were modeled by using Langmuir adsorption isotherm (LAI). The calculated LAI parameters were within the appropriate limits, which proved that the developed NM can be used as an effective material for cadmium removal. Moreover, a new, rapid, and feasible synthesis strategy for the synthesis of Ca3(PO4)2 NM was presented in the literature. [ABSTRACT FROM AUTHOR]

The most promising eco-friendly green synthesized iron nanoparticles (FeNPs) using jujube leaf extract to decolorize methylene blue (MB) dye was established. Synthesized nanoparticles were characterized through different techniques like TEM, SEM, and FTIR. Various parameters such as dye concentration (5 to 20 mg L−1), nanoparticles load (0.5 to 2.5 mg), temperature, pH, and contact time (30 to 150 min) were optimized. A maximum MB dye removal efficiency of 93.5% is achieved at a time interval of 150 min, temperature 30 °C and pH 9 with 2.5 mg FeNPs for a concentration of 20-mgL−1 methylene blue. The adsorption behavior was monitored using a wide range of isotherm models which includes Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin. The Elovich and intraparticle diffusion models, as well as the dynamical models of pseudo-first- and pseudo-second order has been analyzed for the data obtained from dynamic adsorption. Experimental results were consistent along the paradigm of pseudo-second order. Langmuir adsorption isotherm well suited for adsorption data across exclusive concentration range in comparison to other models. The green synthesized FeNPs has high sorption capacity (1000 mg/g) and environmentally friendly in nature, makes it a potential candidate for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the potential application of activated Sargassum aquifolium macroalgae (ASAM) as a biosorbent for uranium(VI) and thorium(IV) ions, employing controlled experimental conditions. The parameters examined included pH, biosorbent mass, initial concentration, contact time, and temperature. To enhance sorption characteristics, the raw Sargassum aquifolium macroalgae (SAM) biomass underwent separate pre-treatments using phosphoric acid (H3PO4) and potassium hydroxide (KOH). Various models were employed to analyze the kinetic and sorption isotherm data, and thermodynamic parameters were determined to assess the sorption mechanism. The KOH-treated SAM demonstrated a higher capacity for biosorbing U(VI) and Th(IV) compared to the acid-treated biomass. The sorption mechanism was investigated through characterization techniques such as FTIR, SEM/EDS, XRD, Zeta-potential, and BET analysis. The desorption-sorption cycle efficiency of both sorbents was evaluated, indicating that 0.1 mol L-1 HNO3 exhibited the most efficient desorption reagent for both metal cations over five consecutive cycles. These findings suggest the potential of ASAM as a biosorbent for removing U(VI) and Th(IV) from aqueous solutions. Furthermore, the study demonstrated the remarkable effectiveness of the two activated sorbents in eliminating U(VI) and Th(IV) ions from real wastewater samples. [ABSTRACT FROM AUTHOR]

Textile wastewater containing heavy metal ions has become a severe environmental problem worldwide. The combined uptake of heavy metals and dyes from wastewater discharged by different sectors is a challenging concept. This study explores the use of hybrid adsorbent based on magnetic chitosan (MC) and magnetic poly glycidyl methacrylate (Mp(GMA)) in adsorption technology, for simultaneous removal of Eriochrome Black T (EBT) dye and chromate anions from their binary aqueous solution. The adsorbent material was functionalized by loading diethylenetriamine (DETA) or dithizone to improve their adsorption capacity (R-DETA or R-Dithizone). The physicochemical characteristics of the materials have been characterized by a wide variety of analytical techniques. Pseudo-second order kinetic model and Langmuir adsorption isotherms were the best-fit models in the binary adsorption system. The co-presence of these anions in the binary solution increases the adsorption capacity of chromate and diminishes the EBT adsorption capacity of the investigated adsorbents (R-DETA and R-Dithizone). The adsorption capacity at monolayer saturation capacities (Langmuir) of R-DETA in binary system were 0.782 and 4.11 mmol g−1 towards EBT and chromate anions respectively, while R-Dithizone adsorbent recorded lower monolayer sorption capacity for EBT (0.490 mmol g−1) and higher sorption capacity for chromate 5.93 mmol Cr(VI) g−1 in the binary solution. The effects of competitive anions Cl−, NO3−, SO42−, and MnO4− on the adsorption of EBT and chromate anions in their binary mixture were examined. The good sorption ability of EBT and Cr(VI) anions against ionic interference supported their use in wastewater treatment applications. NaOH (0.5 M) proved the most effective for desorption from their binary mixture. [ABSTRACT FROM AUTHOR]

An eco-friendly approach was used to fabricate zinc oxide nanoparticles (ZnO NPs) using thyme, Thymus vulgaris L., leaf extract. The produced ZnO nanoparticles were characterized by XRD and SEM analysis. The ZnO NPs showed remarkable adsorption efficiency for tetracycline (TC) from water systems, with a maximum removal rate of 95% under optimal conditions (10 ppm, 0.10 g of ZnO NPs, pH 8.5, and 30 min at 25 °C). The adsorption kinetics followed the pseudo-2nd-order model, and the adsorption process fitted the Temkin isotherm model. The process was spontaneous, endothermic, and primarily chemisorptive. Quantum chemistry calculations, utilizing electrostatic potential maps and HOMO-LUMO gap analysis, have confirmed the stability of the TC clusters. This study suggests that green synthesis using plant extracts presents an opportunity to generate nanoparticles with properties suitable for real-world applications. [ABSTRACT FROM AUTHOR]

In this study, a novel naphthalene-based covalent organic polymer (N-COP) was synthesized and investigated as an advanced adsorbent for the efficient removal of Methylene Blue (MB) from aqueous solutions. The polymer was synthesized through a polycondensation reaction between cyanuric chloride and 1,5-dihydroxynaphthalene, followed by thorough purification. Comprehensive characterization was performed using Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) surface area analysis, and Field Emission Scanning Electron Microscopy (FE-SEM), confirming the successful formation of the porous polymer with a high surface area and thermal stability. Key adsorption parameters including pH, contact time, and initial MB concentration were systematically optimized. The adsorption behavior followed the Langmuir isotherm model under conditions of pH 7 and a contact time of 30 min, indicating a maximum uptake capacity of 90.09 mg/g, while kinetic analysis revealed a strong fit with the pseudo-second-order model. These results demonstrate that N-COP is a promising candidate for environmental applications (in compression with other adsorbents), particularly in the removal of MB from wastewater, offering an eco-friendly, high-efficiency solution to mitigate water pollution. [ABSTRACT FROM AUTHOR]