Optimum Adsorption Conditions Research Articles

Ultrasonic assisted adsorption of methylene blue using blood clam shell as a low-cost adsorbent

Methylene blue is a synthetic dye used in various industries, such as wood, linen, and silk. Generally, as much as 10–200 mg/L of methylene blue is released into the environment and potentially polluting the environment. One of methylene blue removal method from wastewater is adsorption, particularly using blood clam (Anadara granosa) shells adsorbent. Blood clam shells contain CaCO3 (up to 98.7 %) that can be utilized to adsorb methylene. Furthermore, methylene blue adsorption can be enhanced by employed the ultrasonic wave. This research aims to prepare, characterize, and employ blood clam shells as a low-cost adsorbent in the ultrasonic-assisted methylene blue adsorption. The parameters studied were the adsorbent preparation method, adsorbate pH, adsorbent mass, contact time, and initial concentration. The adsorbent preparation method affected the morphology, elemental composition, functional groups, and average particle size, which were confirmed using SEM-EDX, FTIR, and PSA, where this kind of investigation has never been conducted before. Optimum conditions for methylene blue adsorption were obtained for adsorbent A3, pH 12, adsorbent mass of 0.5 g, contact time of 60 min, and initial concentration of 10 ppm, with a removal percentage of 98.614 %. This removal percentage increased by 63.119 % (espescially in A3) compared to without ultrasonic waves, which could only remove methylene blue by 35.495 %. Ultrasonic-assisted adsorption of methylene blue using blood clam shells adsorbent proceeded according to the Sips isotherm model (R2 = 0.9953) and pseudo-second-order kinetics (R2 = 0.939). A3 shows an extraordinary performance, with reusability up to six cylces. The adsorption occurs by electrostatic interaction between adsorbent's surface and cations in methylene blue, chemisorption, and the formation of monolayer adsorbate in heterogenous A3's surface.

Resourceful exploitation of sedimentary clay: Designing a dual-chambered borosilicate glass reactor system for the efficient treatment of malachite green and phenol through SCRT adsorption and 5%Fe@SRCT catalysis via CWPO, with evaluation of seed germination and fish survival.

This study presents an innovative double-walled borosilicate glass reactor system for the efficient treatment of liquid and gaseous wastewater. This reactor system allows precise temperature control, continuous pH monitoring, and controlled dosing of reagents to optimize reaction conditions. Detailed characterization was carried out by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), BET (specific surface area) analysis, point of zero charge (PZC), and scanning electron microscopy (SEM) for the SCR, SCRT, and 5%Fe@SCRT materials. For Malachite Green adsorption, SRCT demonstrated a maximum adsorption capacity of 39.78 ±0.5mg/g using the Langmuir isotherm model and followed pseudo-second-order kinetics. Optimum conditions for adsorption were found to be: an initial concentration of 50 ppm, an adsorbent dosage of 1g/l, a pH of 8.5, and a temperature of 50°C. For the catalytic oxidation of phenol, 5%Fe@SRCT achieved a remarkable removal rate of 99.9±0.1% under optimum conditions (50 ppm phenol, 1g/l catalyst dosage, pH3.5, H2O2 concentration 8.7mM, and temperature 70°C). Intermediates identified during the reaction included hydroquinone, benzoquinone, catechol, and resorcinol, with degradation occurring over a 60-minute reaction period. The 5%Fe@SCRT material showed excellent reusability in the removal of phenol by catalytic oxidation, with no significant loss of efficiency over three cycles, while the SRCT underwent three cycles of regeneration for the adsorption of Malachite Green. Scavenger tests confirmed the involvement of hydroxyl radicals in the catalytic oxidation process. In addition, fish survival tests after catalytic oxidation of phenol by 5%Fe@SRCT showed no impact on fish, underlining the environmental safety of this process. In addition, germination tests after decolorization of MG by SRCT demonstrated a good effect with no negative impact, reinforcing the ecological value of this innovative technology. These results highlight the innovative use of SCRT and 5%Fe@SCRT as versatile materials for environmental remediation, exploiting their effective adsorption capacities and efficient catalytic oxidation performance within the proposed double-walled borosilicate glass reactor system. PRACTITIONER POINTS: The study demonstrates the effectiveness of an innovative reactor system employing SRCT adsorbent and Fe@SRCT catalyst for efficient removal of malachite green and phenol from wastewater. Environmental impact assessment, including seed germination and fish survival evaluation, validates the method's eco-friendly potential. Implementation of this approach could significantly contribute to sustainable water treatment practices.

Insight into adsorption-desorption of methylene blue in water using zeolite NaY: Kinetic, isotherm and thermodynamic approaches

It is critical to find an efficient method to separate methylene blue (MB) in wastewater before discharging them into environment. Adsorption using zeolites is the most commonly used one. To determine adsorption mechanism providing useful data to enhance adsorption capacity and practicability of scale-up, kinetic, isotherm and thermodynamic adsorption were evaluated and discussed intensely. Zeolite NaY was synthesized from rice husk ash with a one-stage process. Effects of pH, contact time, initial concentration, adsorbent dose, temperature, solvents and recyclic stability on MB adsorption and desorption were investigated in detail via alternating variable method. Optimal conditions for adsorption were at pH 8, 1 h, 50 mgMB/L, 303K. Adsorption kinetics and isotherms showed that the process fitted to pseudo-second-order, Freundlich and Temkin isotherm, indicating a spontaneous, exothermic and physical adsorption process with multilayer adsorption. Desorption process showed that EtOH:H2O (1:1) solvent at 323K was optimal for releasing MB and its thermodynamic studies revealed that this process was favorable with rising temperature. The maximum adsorption capacity was calculated as 49 mg/g and the adsorbent could maintain its adsorption performance after six cycles. Generally, this study provided a comprehensive approach of an efficient, cost-effective, and recyclable NaY for MB removal from water.

Adsorptive removal of anticarcinogen pazopanib from aqueous solutions using activated carbon: isotherm, kinetic and thermodynamic studies

Pazopanib, which is dangerous for aquatic environments due to its toxic and bioaccumulation potential, has been detected at different concentrations in oncology hospital wastewater, sewage, and surface waters. This study aimed to remove pazopanib from wastewater by activated carbon adsorption technique. The effect of the main variables such as initial concentration, pH of pazopanib solution, adsorbent dose, contact time of the phases, and temperature on the adsorption process was evaluated and the optimum adsorption conditions were determined. The experimental data were applied to Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption isotherm models to describe the adsorption behavior. The experimental data were applied to pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic models to describe the adsorption kinetics. Isotherms were established in the 20–50 °C temperature range to study the adsorption equilibrium. According to the results, the highest removal efficiency of pazopanib (95.87%) was obtained at initial concentration (100 mg L−1), adsorbent dose (0.30 g L−1), temperature (20 °C), contact time (120 min) and pH (7.0). The adsorption kinetics was well described by the pseudo-second-order kinetic model (R2 = 0.9998) and the adsorption isotherm by the Langmuir model (R2 = 0.9999). In thermodynamic studies, the negative values of standard enthalpy (ΔH°), standard free enthalpy (ΔG°), and free entropy (ΔS°) indicate that the adsorption process is spontaneous and favorable, i.e. the disorder is reduced. These results indicate that the developed adsorption process can be efficiently and spontaneously applied for the removal of pazopanib from aqueous solutions.

Treatment of the Textile Wastewater using Malaysian Ganoderma lucidum Mycelial Pellets

Purification of textile wastewater using biomass and in particular different fungi is gaining exponential interest to minimize the impacts of current physical-chemical and biological wastewater treatment by-products. This study investigates the potential of Malaysian Ganoderma lucidum mycelium pellets (GLMP) for the decontamination of wastewater samples received from a commercial textile manufacturer. All studies were performed under ambient temperature (26-35 ℃) and unsterilized conditions using a simple bioreactor design (stirred batch bioreactor) for a more practical assimilation of the current available wastewater treatment process system. The optimal conditions of adsorption by GLMP were determined by variation effects of adsorbent concentration (0, 8.75, 12.5 and 25 g/L), pH (unadjusted 7.10 – 8.22, 4 and 6), and wastewater dilution factor (1:0, 1:4, and 2:3, v/v). This method was proved to be effective in both decolorization and chemical oxygen demand (COD) reduction, simultaneously. The most significant percentage of decolorization observed was 77.24% in a 72 h treatment, whereas COD reductions were 78.32% in a 36 h treatment. The present study fits both Langmuir and Freundlich adsorption isotherms as the values of R2 both model were close to 1, indicating the favorable adsorption of dyes towards Malaysian GLMP.

Utilizing Chamaerops humilis in removing methylene blue dye from water: an effective approach.

Removing dyes, particularly methylene blue, from wastewater is crucial due to their detrimental effects on environmental and human health. Adsorption, recognized as a simple and efficient technique, is frequently employed to eliminate various dyes from water. Although activated carbon is a favored adsorbent for wastewater treatment, its high cost often restricts its use. As a result, there is increasing interest in utilizing inexpensive, natural materials, and waste products as alternative adsorbents. Sawdust from the European fan palm tree, specifically Chamaerops humilis, a widely available and cost-effective by-product, has demonstrated effective dye removal from wastewater. This study explored the impact of various factors such as time, agitation, adsorbent quantity, dye concentration, pH, and temperature on the adsorption of methylene blue using Chamaerops humilis sawdust. Optimal dye adsorption conditions were identified at a temperature of 25 °C, a pH of 8, an adsorbent dosage of 100 mg, a contact time of 120 min, and a dye concentration of 20 mg L-1, achieving a removal efficiency of 93.5%. Moreover, the Langmuir isotherm model described the adsorption dynamics more accurately, suggesting a maximum sorption capacity of 22.7 mg g-1 for the sawdust. Additionally, adsorption kinetics aligned better with the pseudo-second-order model than the pseudo-first-order model, underscoring the efficacy of this method in treating dye-polluted water.

Experimental investigation of Cd (II) ion adsorption on surface-modified mixed seaweed Biosorbent: A study on analytical interpretation and thermodynamics

Despite advancements in wastewater treatment technologies, heavy metal contamination, especially cadmium (Cd), severely threatens human health and ecosystems. The purpose of this work is to compare the removal of Cd (II) ions from aqueous solutions by chemically modified mixed seaweed biosorbent (CMSB) and physically modified mixed seaweed biosorbent (PMSB). BET, SEM, EDAX, FTIR, and XRD techniques characterized the mixed seaweed biosorbents before and after adsorption. They are well-known for their sustainability, affordability, and biodegradability. The BET study revealed that CMSB had a surface area of 19.682 m2/g, while PMSB had a lower surface area of 14.803 m2/g. The optimum adsorption conditions were a temperature of 303 K, pH of 6.0, and biosorbent dosages of 1 g/L for CMSB and 2.5 g/L for PMSB. For CMSB and PMSB, the most efficient contact times were 40 and 80 min, respectively. The Langmuir model was demonstrated to be the best fit for the experimental data when compared to other isotherm models, with a coefficient of determination, or R2, of 0.9713 and a maximum monolayer capacity of 151.2 mg/g and 181.6 mg/g for physical and chemical activated mixed seaweed biomass. There was a significant relationship between the R2 values of chemically modified and physically modified biomass. The findings demonstrate that pseudo-second-order kinetics more accurately represent the adsorption process than pseudo-first-order and Elovich models. Thermodynamic experiments validated the endothermic, spontaneous and favourable characteristics of the removal process. According to the results of the current study, PMSB and CMSB may be used as effective adsorbents to remove Cd (II) from aqueous solutions.

Synergistic effect of adsorption and photolysis on methylene blue removal by magnetic biochar derived from lignocellulosic biomass

In this study, magnetic biochar was synthesized by doping Fe3O4 onto the biochar surface followed by analysis of its properties. The efficiency of methylene blue (MB) removal through the combined processes of adsorption and photolysis was assessed. The presence of Fe3O4 on the biochar surface was confirmed using Raman spectroscopy and X-ray photoelectron spectroscopy. The magnetic biochar, after MB adsorption, showed a magnetism of 39.50 emu/g leading to a 97.07 % recovery rate. The specific surface area of biochar was higher (380.68 m2/g) than that of magnetic biochar (234.46 m2/g), and the maximum adsorption capacity of MB was higher in the biochar (0.03 mg/g) than that in magnetic biochar (0.02 mg/g) under the optimal conditions for MB adsorption. The MB adsorption experiments using biochar or magnetic biochar were optimally conducted under 10–20 mg/L MB concentration, 1 g biochar dosage, pH 12, 200 rpm rotation speed, 25 °C temperature, and 30 min duration. Under dark conditions, biochar had a higher MB removal rate, at 83.91 %, compared to magnetic biochar, at 78.30 %. Under visible light (λ > 425 nm), magnetic biochar effectively removed MB within 10 min, highlighting the synergistic effect of adsorption and photolysis. MB is physically and chemically adsorbed by the monolayer on the surface of EB and EMB according to adsorption behavior.

Enhanced removal of methylene blue and procion deep red H-EXL dyes from aqueous environments by modified-bentonite: Isotherm, kinetic, and thermodynamic

This study aims to enhance local bentonite's effectiveness in removing methylene blue and procion deep red dyes from aqueous media through organic modification with cetyltrimethylammonium bromide surfactant. Raw and modified bentonites were analyzed using XRF, XRD, FTIR, BET/BJH, and DSC techniques. The modified bentonite showed a crystalline structure and mesoporous morphology with a heterogeneous surface. Optimal adsorption conditions for MB dye were 0.2 g adsorbent dose, 60 min contact time, 60 mg/L initial concentration, and pH 8, achieving a maximum sorption capacity of 6.418 mg/g. For PDR dye, optimal conditions were a 0.125 g adsorbent dose, 40 mg/L initial concentration, 30 min contact time, and acidic pH, with a maximum adsorption capacity of 8.503 mg/g. Isotherm analysis indicated the Langmuir model best fits the adsorption data, suggesting a mono-layer adsorption process. Kinetic investigations revealed that the adsorption follows a pseudo-second-order model, indicating a chemisorption mechanism. Thermodynamic results showed exothermic adsorption for MB and endothermic adsorption for PDR. This work highlights the potential of surfactant-modified bentonite as a cost-effective sorbent for treating polluted aqueous systems, effectively removing both cationic and anionic dyes.

Adsorptive removal of oxytetracycline antibiotics on magnetic nanoparticles NiFe2O4/Au: Characteristics, mechanism and theoretical calculations

This investigation aims to develop a specialized adsorbent for the efficient removal of Oxytetracycline (OTC) from complex matrices. We employed a magnetic composite, NiFe2O4/Au (NFO/Au), as the adsorbent, which exhibited remarkable ease of material recovery due to the reasonable magnetic property of NFO. Simultaneously, gold nanoparticles (AuNPs) on the NFO surface amplified the material's adsorption capacity by demonstrating a strong affinity for the amine groups within the OTC structure. The crystal and morphological structure and surface chemistry of the prepared material were identified by XRD, TEM, BET, and XPS. Their magnetic and optical properties were studied by VSM and UV-VIS. Cubic or rectangular shapes (50–100 nm) of NFO were surrounded by spherical AuNPs (10–30 nm). The saturation magnetization slightly decreased from 33 emu/g to 30 emu/g upon coating the NFO surface with AuNPs, which still ensures good magnetism of the composite. A maximum adsorption capacity of 43.48 mg/g was achieved at optimum adsorption conditions. The novel adsorbent exhibits fast adsorption after 30 min, high adsorption capacity, and good reusability after five cycles. The adsorption equilibrium adhered to a monolayer Langmuir isotherm, while the adsorption kinetics followed pseudo-second-order kinetics and the intraparticle diffusion models. The first principle calculation based on the density functional theory revealed that the fundamental reason behind the enhanced adsorption capacity is through greater electron populations, more negative binding energy, and higher effective charge transfer. This composite material was employed to remove OTC from water samples taken from a shrimp pond, demonstrating an impressive adsorption efficiency of approximately 90 %.

Efficiently selective adsorption Rb(I) based on ion-imprinted membrane chromatography: Batch adsorption and dynamic filtration

The development of efficient separation and enrichment methods for rare and precious metal rubidium (Rb) has attracted more and more attention the hydrometallurgy. Here, based on the phenolic hydroxyl-rich copolymer poly(styrene-co-4-hydroxylstyrene) (P(S-co-VPh)), the Rb+ imprinting nanofiber membrane (P(S-co-VPh)-(IIP)) was prepared using electrostatic spinning. NMR, FTIR, XPS, FESEM and EDS were used to comprehensively characterize the composition and structure of the copolymer and nanofiber membranes. Batch adsorption results indicated that the optimal adsorption conditions were pH = 9 at room temperature, and the process of Rb+ adsorption was spontaneous exothermic reaction. Ion imprinting technology not only enhanced adsorption capacity and recycling performance of the P(S-co-VPh20)-(IIP) membrane, but more importantly, significantly improved its selectivity, so that the selectivity coefficient (β) of Rb+/Mn+ for the interfering ions Na+, Mg2+, Ca2+, and K+ were 1438.17, 864.38, 434.6, and 307.25, respectively. The adsorption kinetics fitted well to the pseudo-second-order rate expression, and the maximum theoretical adsorption capacity (qm) could reach 140.00 mg/g from the Langmuir model fitting. The dynamic filtration experiment of the stacked membranes chromatography indicated that the breakthrough times were significantly affected by the different operation conditions (Flow rate, initial Rb+ concentration and membrane dosage). Among the four typical models of Thomas, Yoon-Nelson, EXY and BJP, the breakthrough curves can be well described by the EXY model.

Enhanced cytotoxic efficacy against MCF-7 and HCT116 cell lines and high-performance cefoperazone removal using biogenically synthesized CeO2 nanoparticles

The biosynthesis of cerium oxide nanoparticles “CeO2 NPs” using an aqueous Echinacea purpurea leaf extract (EP) was conducted. EP extract is a great source of organic compounds, such as polyphenols and flavonoids, with high antioxidant activity, providing a high degree of stabilizing and capping for the formed CeO2 NPs. Physicochemical and related morphological properties of the as-biosynthesized CeO2 NPs were explored using diverse analytical techniques. Results showed that the as-prepared CeO2 NPs were crystalline pure spherical with a cubic system, with an average crystallite size of 10.8nm as determined by XRD, and an average particle size of 12.3 nm as determined via TEM. A large surface area of 100.3 m²/g with a monodispersed phase with a crystallinity index of 1.2 was achieved. Moderate stability with Zeta potential of -27.8 ± 0.20 mV and PDI 0.126 ± 0.031 were illustrated. The cytotoxicity of the as-biosynthesized CeO2 NPs against two types of cell lines, MCF7 and HCT116 was studied, showing promising impacts where the IC50 values for MCF7 and HCT116 were found to be 78.5 and 128.8 µg/mL, respectively. Additionally, the adsorption technique of the as-prepared CeO2 NPs was studied for the removal of cefoperazone. The study demonstrated that the adsorption followed the Langmuir isothermal model with a maximum loading capacity of 201.4 mg/g and a pseudo-second-order kinetic model. Therefore, the as-biosynthesized CeO2 NPs have promising potential as an anticancer agent and for pharmaceutical wastewater remediation. Also, Cefo@CeO2 NPs were carefully prepared after the determination of the optimum adsorption conditions. Antibacterial activity for both the as-prepared CeO2 NPs and Cefo@CeO2 NPs against gram-positive (S. aureus and B. subtilis) and gram-negative (P. aeruginosa, B. cepacia, E. coli, and S. typhimurium) bacteria was conducted. Cefo@CeO2 NPs exhibited a dose-dependent response, with significant synergistic effects reaching 76 % and 82 %-fold increase for P. aeruginosa and B. cepacia respectively, indicating promising potential for combating bacterial infections.

Synthesis and characterization of a novel TiO2@chitosan/alginate nanocomposite sponge for highly efficient removal of As(V) ions from aqueous solutions: Adsorption isotherm, kinetics, experiment and adsorption mechanism optimization using Box-Behnken design

This research uses a novel TiO2@CSC.Alg composite sponge was created by encasing TiO2 nanoparticles in the natural polymers alginate and chitosan, resulting in a nanocomposite that is both ecologically friendly and biocompatible. Using the generated nanocomposite as a new environmentally friendly adsorbent, As(V) heavy metal ions were effectively removed from aqueous media. The following techniques were used to analyse the physicochemical properties of the obtained materials: pHZPC, FTIR, XRD, BET, SEM, and XPS. Utilizing nitrogen adsorption/desorption isotherms, the TiO2@CSC.Alg composite sponge's textural properties were identified. This revealed a BET surface area of 168.42 m2/g and a total pore volume of 1.18 cc/g, indicating its porous nature and potential for high adsorption capacity. Examine the effects of temperature, pH, dose, and beginning concentration on adsorption. The adsorption characteristics were determined based on equilibrium and adsorption kinetics measurements. The adsorption process was both pseudo-second-order (PSOE) and Langmuir isothermally fit. Chemisorption was the adsorption method since the adsorption energy was 25.45 kJ·mol−1. An endothermic and spontaneous adsorption process was indicated by more metal being absorbed as the temperature increased. The optimal conditions for adsorption were optimized via Box-Behnken design software to be pH of 5 in the solution, a dosage of 0.02 g of the TiO2@CSC.Alg composite sponge per 25 mL, and an arsenate (As(V)) solution the adsorption capacity was 202.27 mg/g are ideal for efficient adsorption. These parameters are critical in achieving the maximum adsorption capacity of the composite sponge for arsenate, which could be beneficial for water purification applications. Utilizing Design-Expert software's response surface methodology (RSM) and Box-Behnken design (BBD), the adsorption process was optimized with the fewest planned tests. After six successive cycles of adsorption and desorption, the adsorbent stability was confirmed by the adsorbent reusability test without any noticeable decrease in removal efficacy. Additionally, it displayed good efficiency, the same XRD and XPS data before and after reuse, and no change in chemical composition.

Adsorption performance and mechanism of pectin modified with β-cyclodextrin for Zn2+ and Cu2+

Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with green, stable and high-efficiency for adsorption of heavy metals, pectin β-cyclodextrin composite was successfully prepared and used for Zn2+ and Cu2+ adsorption for the first time. Various variables that influence the adsorption performance were explored, and the optimal adsorption conditions were determined. According to the pseudo-second-order kinetic model, the adsorption process of Zn2+ and Cu2+ by the adsorbent was mainly chemical adsorption. The adsorbent adsorption process was an exothermic and non-spontaneous process. According to the Langmuir isotherm model, the maximum adsorption capacity was 12.51 ± 0.33 and 24.98 ± 0.23 mg/g for Zn2+ and Cu2+, respectively. The FTIR, EDX and XPS results revealed that the main mechanisms of removing pollutants by adsorbent were ion exchange and coordination. In addition, electrostatic attraction and chelation were present in the adsorption process. After five adsorption desorption cycles, the pectin β-cyclodextrin composite adsorbent still exhibited adsorption and regeneration capabilities. This study provides a low-cost, effective and simple method for preparation of modified pectin, which has excellent application potential in the removal of heavy metal ions from wastewater.

Comparative study on vanadium(V) adsorption performance of supported ionic liquid synthesized by physical impregnation and chemical grafting

This study loaded ionic liquids (ILs) onto chloromethylated polystyrene resins using physical impregnation and chemical grafting. The resulting ionic liquid-loaded resins were characterized using SEM-EDS, FTIR, and NMR spectral analyses, confirming the successful preparation of both the physical impregnation resin (PIR) and the chemical grafting resin (CGR). The study compared the influencing conditions, cyclicity, selectivity, and adsorption mechanism of PIR and CGR on adsorption vanadium(V). Under optimum adsorption conditions, CGR exhibited significantly higher adsorption capacity (261 mg/g) than PIR (27 mg/g). In terms of adsorption selectivity, the separation coefficients of CGR for Fe and Al (65.3 and 45.4) were much larger than those of PIR (6.3 and 10.6). Furthermore, the CGR exhibited a cycling capacity 1.5 times greater than the PIR, maintaining an adsorption capacity of over 98 % of the initial value within 12 cycles. Based on the adsorption mechanism, both loaded resins conform to the monolayer chemisorption described by Langmuir isothermal adsorption model and the pseudo-second-order kinetic model. The results showed that the adsorption performance, selectivity, and adsorption stability of CGR were considerably superior to those of PIR. A further comparison with numerous previous research results revealed that the adsorption capacity of CGR for vanadium was significantly increased, and the cycling performance was substantially enhanced, while the separation between it and the impurity ions was also improved.

Sodium alginate-encapsulated nano-iron oxide coupled with copper-based MOFs (Cu-BTC@Alg/Fe3O4): Versatile composites for eco-friendly and effective elimination of Rhodamine B dye in wastewater purification

This study explores the effectiveness of Alginate-coated nano‑iron oxide combined with copper-based MOFs (Cu-BTC@Alg/Fe3O4) composites for the sustainable and efficient removal of Rhodamine B (RhB) dye from wastewater through adsorption and photocatalysis. Utilizing various characterization techniques such as FTIR, XRD, SEM, and TEM, we confirmed the optimal synthesis of this composite. The composites exhibit a significant surface area of approximately 160 m2 g−1, as revealed by BET analysis, resulting in an impressive adsorption capacity of 200 mg g−1 and a removal efficiency of 97 %. Moreover, their photocatalytic activity is highly effective, producing environmentally friendly degradation byproducts, thus underlining the sustainability of Cu-BTC@Alg/Fe3O4 composites in dye removal applications. Our investigation delves into kinetics and thermodynamics, revealing a complex adsorption mechanism influenced by both chemisorption and physisorption. Notably, the adsorption kinetics indicate equilibrium attainment within 100 min across all initial concentrations, with the pseudo-second-order kinetic model fitting the data best (R2 ≈ 0.999). Furthermore, adsorption isotherm models, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, elucidate the adsorption behavior, with the Temkin and Dubinin-Radushkevich models showing superior accuracy compared to the Langmuir model (R2 ≈ 0.98 and R2 ≈ 0.96, respectively). Additionally, thermodynamic analysis reveals a negative Gibbs free energy value (−6.40 kJ mol−1), indicating the spontaneity of the adsorption process, along with positive enthalpy (+24.3 kJ mol−1) and entropy (+82.06 kJ mol−1 K) values, suggesting an endothermic and disorderly process at the interface. Our comprehensive investigation provides insights into the optimal conditions for RhB adsorption onto Cu-BTC@Alg/Fe3O4 composites, highlighting their potential in wastewater treatment applications.

Molecularly imprinted polymer based on deep eutectic solvent as functional monomer for paracetamol adsorption

Paracetamol, a popular analgesic, has been linked to harmful health effects, such as kidney and liver damage. The detection of paracetamol in the environment and its overdose use in humans and animals has raised global concerns, highlighting the need for its efficient removal or detection in real samples. In this study, a deep eutectic solvent-molecularly imprinted polymer (DES-MIP) was synthesized and applied as an adsorbent to recognize the removal of paracetamol selectively. DES-MIP was synthesized using a deep eutectic solvent (DES) as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and paracetamol as a template. DES was initially prepared by combining choline chloride (ChCl) with methacrylic acid at a molar ratio of 1:2. A deep eutectic solvent-non-imprinted polymer (DES-NIP) was synthesized as a control. The characterization analysis, including Fourier transform infrared spectroscopy (FTIR), Scanning emission microscopy (SEM), and Brunauer-Emmett-Teller (BET) was conducted for both polymers to confirm the synthesis occurred. The selectivity study inferred that DES-MIP (15.95 mg/g) was more selective towards paracetamol than DES-NIP (7.00 mg/g). Response surface methodology (RSM) coupled with central composite design (CCD) was employed to examine the effect of pH, contact time, and dosage on paracetamol adsorption. The analysis of variance (ANOVA) demonstrated the relative significance of process parameters in the adsorption process. The contact time and dosage were found to be more significant than the pH. The result indicated that the optimal conditions for paracetamol adsorption were pH 7, 35 min, and 5.5 mg. The behavior of paracetamol adsorption on DES-MIP was well-fitted using the second-order kinetic and Langmuir isothermal models, respectively. Then, the DES-MIP with optimized parameter studies was applied to herbs, medicine, and dietary supplements, achieving good recoveries of 94.46 %, 86.79 %, and 85.13 % and relative standard deviations (RSD) of 1.15 %, 2.39 %, and 2.52 %, respectively.

Investigating the adsorption of Malachite green and Methyl green onto synthesized Ni0.5Zn0.5Fe2O4 spinel ferrites

Nano-sized Ni0.5Zn0.5Fe2O4 spinel ferrites were synthesized at the nanoscale by the co-precipitation method via a sonochemical approach. High-intensity ultrasonic radiation treated the hydroxide suspension at 90 °C for 2 hours. Both the X-ray diffraction analysis (XRD) and the Fourier transform infrared spectra (FT-IR) analysis confirm the presence of the cubic spinel phase with a grain size of 15 – 25 nm. The vapor adsorption experiments confirmed that the pore surface area was found to be 95.34 m2/g by N2 adsorption desorption isotherm, and the material was mesoporous. The saturation magnetization of ferrite powders was investigated using a vibrating sample magnetometer (VSM). This work mainly focuses on the removal of Malachite green (MaG) and Methyl green (MG) with the help of adsorption technology from water using Ni0.5Zn0.5Fe2O4 spinel ferrites. The adsorption studies examined the impact of mass and pH, revealing that both factors influence adsorption. The optimum conditions for Malachite green and Methyl green adsorption onto the spinel Ni-Zn ferrites were 0.02 g for spinel mass, pH values (6−8). At 328 K, the maximum capacity for Ni0.5Zn0.5Fe2O4 spinel adsorbents was 82 and 180 mg/g MaG and MG, respectively. The removal efficiency for MaG and MG dye was respectively 95 % in 420 and 180 minutes. According to the kinetic studies, a pseudo-second-order model is the most suitable model for the adsorption process. The adsorption mechanism was examined by fitting the adsorption data to Langmuir, Freundlich, Radushkevich, and Temkin adsorption models. The Langmuir model can adequately describe results.

Imidacloprid removal by modified graphitic biochar with Fe/Zn bimetallic oxides

Coping with the critical challenge of imidacloprid (IMI) contamination in sewage treatment and farmland drainage purification, this study presents a pioneering development of an advanced modified graphitic white melon seed shells biochar (Fe/Zn@WBC). The Fe/Zn@WBC demonstrates a substantial enhancement in adsorption efficiency for IMI, achieving a remarkable removal rate of 87.69% within 30 min and a significantly higher initial adsorption rate parameter h = 4.176 mg g−1·min−1. This significant improvement outperforms WBC (12.22%, h = 0.115 mg g−1·min−1) and highlights the influence of optimized adsorption conditions at 900 °C and the graphitization degree resulting from Fe/Zn bimetallic oxide modification. Characterization analysis and batch sorption experiments including kinetics, isotherms, thermodynamics and pH factors illustrate that chemical adsorption is the main type of adsorption mechanism responsible for this superior ability to remove IMI through pore filling, hydrogen bonding, hydrophobic interaction, electrostatics interaction, π-π interactions as well as complexation processes. Furthermore, we demonstrate exceptional stability of Fe/Zn@WBC across a broad pH range (pH = 3–11), co-existing ions presence along with humic acid under various real water conditions while maintaining high removal efficiency. This study presents an advanced biochar adsorbent, Fe/Zn@WBC, with efficient adsorption capacity and easy preparation. Through three regeneration cycles via pyrolysis method, it demonstrates excellent pyrolysis regeneration capabilities with an average removal efficiency of 92.02%. The magnetic properties enable rapid separation facilitated by magnetic analysis. By elucidating the efficacy and mechanistic foundations of Fe/Zn@WBC, this research significantly contributes to the field of environmental remediation by providing a scalable solution for IMI removal and enhancing scientific understanding of bimetallic oxides-hydrophilic organic pollutant interactions.

Cobalt(II) removal with dolomite: Use of radiotracer technique in aqueous solution

Industrial processes have the potential to release cobalt into the environment, and exposure to cobalt in quantities higher than specific amounts can have harmful impacts on living organisms. This study aimed to determine whether natural dolomite from the Thrace region of Türkiye could effectively remove Co(II) from aqueous solutions. Batch studies were conducted to examine the impact of various experimental factors, including adsorbent dosage, initial Co(II) concentration, contact time, solution pH, and temperature. The cobalt concentrations in aqueous solutions were determined by employing 60Co radionuclide as a radiotracer. Experimental results revealed that optimum adsorption conditions were obtained at a solid-liquid ratio of 20 g·L−1, initial Co(II) concentration of 128 mg·L−1, contact time of 120 min, and pH 6 with a maximum adsorption capacity of 2.32 mg⋅g−1. The pseudo-second-order kinetic and Redlich-Peterson isotherm models described the experimental data well. The adsorption process of Co(II) ions on the dolomite was spontaneous and exothermic. The results showed the potential use of dolomite to remove such a toxic metal ion from industrial wastewater.