Adsorbent For Water Treatment Research Articles

Efficient biochar regeneration for a circular economy: Removing emerging contaminants for sustainable water treatment

Biochar is widely known as a highly effective adsorbent for water treatment, capable of removing a wide range of pollutants. However, its saturation point limits its long-term use, but regeneration can extend its applicability. This study aims to develop a sustainable method for removing pollutants from water that aligns with the concept of the circular economy. Biochar derived from forest residue was used to remove emerging pollutants such as fipronil (FIP), venlafaxine (VEN), sulfamethoxazole (SMX) and trimethoprim (TRM). A comparative analysis of the adsorption of the studied pollutants onto biochar was performed by analyzing the kinetics, where it was found that SMX exhibited the lowest adsorption efficiency, prompting further optimization experiments. Under optimal conditions, adsorption isotherms were used to investigate the pollutant removal mechanisms. The results showed that biochar exhibited high adsorption capacities for FIP, VEN, SMX and TRM, which were 3.77, 2.09, 2.71 and 3.88 mg/g, respectively. Regeneration treatments were applied to remove adsorbed contaminants after biochar saturation. Among them, heat-activated persulfate showed the most effective regeneration, maintaining biochar's adsorption capacity after five cycles with no significant loss. Eventual morphological, structural and chemical alterations post-regeneration were assessed using different characterization techniques. The findings of this research highlight the potential of biochar for sustainable water treatment, supporting the circular economy by extending its life cycle through effective regeneration.

Construction and demolition waste as a low-cost adsorbent for water treatment: kinetics, isotherm, thermodynamics, and Fenton regeneration.

The present study proposes to investigate the feasibility of using construction and demolition waste (CDW) as an aqueous remediation agent through adsorption. The CDW, with and without chemical and thermal pre-activation, was evaluated to remove the methylene blue (MB) dye from the water solution. Variables interfering with adsorption processes, such as adsorbent dosage, solution pH, and particle size, were evaluated. The material was characterized by pHZPC, FTIR, XRD, SEM, EDS, and TG. The kinetic and equilibrium data better fitted the Elovich and Sips models, respectively. A maximum adsorption capacity of 18.62mgg-1 at 60°C was observed. Thermodynamic data indicated that adsorption occurred through a spontaneous and favorable process governed mainly by physical processes. The regeneration studies were carried out using processes based on the Fenton reaction, where the catalytic action of the iron naturally present in the CDW was evaluated. The results showed that the desorption balance was the main limiting factor for the effective regeneration of the saturated material. Adding Fe2+ to the system made this process suitable for the regeneration of the CDW and degradation of the pollutant in the aqueous phase. A regeneration efficiency of 65%, maintained practically constant during five adsorption-regeneration cycles, was observed. These results highlight the high potential of using CDWs as an adsorbent material.

Optimization and Efficiency of Novel Magnetic-Resin-Based Approaches for Enhanced Nickel Removal from Water

Nickel contamination in water is a critical issue due to its toxicity and persistence. This study presents a novel magnetic resin, developed by modifying Lewatit® MonoPlus TP 207 with magnetite nanoparticles, to enhance adsorption capacity and facilitate efficient separation. A Definitive Screening Design (DSD) was employed to identify and optimize key parameters affecting nickel adsorption, including pH, resin dosage, initial nickel concentration, and the presence of competing ions (calcium and magnesium). The DSD analysis revealed that pH and magnesium concentration were the most significant factors influencing nickel removal. Optimal conditions were determined as pH 7, 270 min contact time, resin dosage of 0.5 mL/L, initial nickel concentration of 110 µg/L, calcium concentration of 275 mg/L, and magnesium concentration of 52.5 mg/L, achieving a maximum removal efficiency of 99.21%. The magnetic resin exhibited enhanced adsorption capacity and faster kinetics compared to the unmodified resin, leading to more efficient nickel removal. Moreover, its magnetic properties facilitated rapid separation from treated water, offering practical advantages for real-world applications. This study demonstrates the effective use of DSD in optimizing adsorption parameters and underscores the potential of magnetic resin as a sustainable and efficient adsorbent for water treatment.

Porous calix[4]pyrrole-based polymers with high surface area for efficient removal of polar organic micropollutants from water

Herein, effort was made to construct innovative adsorbent for the removal of polar organic micropollutants (OMPs) from water. Tetra-meso resorcinol-functionalized calix[4]pyrrole (CP) featured with endo-functionalized attribute and polyphenol hydroxyl structure was crosslinked by π-electron-rich 4,4′-bis(chloromethyl)biphenyl (BCMBP) through Friedel-Crafts reaction to generate porous calix[4]pyrrole-based polymers (PCPPs) with high surface area. The porosity of the PCPPs could be tuned by adjusting the molar ratio of hydrophilic CP to hydrophobic BCMBP, and diversified binding sites were integrated together. Based on adsorption kinetics and isotherm studies, PCPP(1–16) showed rapid adsorption rate and high removal efficiency (RE) as well as advanced adsorption capacity. The REs towards the tested polar OMPs by PCPP(1–16) were all above 95% in 30 min. Compared with granular activated carbon (GAC), the rate constant of pseudo-second-order model (k2) and adsorption capacity upon PCPP(1–16) were 8–230 times and 1.3–3.1 times greater than those by GAC. Adsorption mechanism studies confirmed the presence of multiple interactions and thermodynamic investigation revealed the spontaneous and physical adsorption nature. Besides, PCPP(1–16) showed excellent adsorption performance in real water samples at environmental levels and exhibited advanced absorption ability in flow-through mode. Accompanied by facile regeneration under eluting with methanol and cost-effective preparation, PCPP(1–16) demonstrated great potential as promising adsorbent for water treatment.

Regulating the Surface State of Carbon Dots as Ultrahigh-Capacity Adsorbents for Water Treatment.

Adsorption is one of the most widely researched and highly effective methods for mitigating the environmental threat posed by recalcitrant dyes in aqueous solutions. This paper presents a solvent-free synthesis method for the rapid and large-scale production of nitrogen (N) and phosphorus (P) co-doped carbon dots (N, P-CDs) which possess specific surface states and outstanding dye adsorption properties. Compared to the undoped CDs, the N, P-CDs not only exhibit a higher yield of solid-state luminescence but also endow them with the efficient adsorption and removal of Congo red (CR) from water. Due to the synergistic effects of π-π stacking, hydrogen bonding and electrostatic attraction, the N, P-CDs exhibit an ultra-high adsorption capacity (3118.87mgg-1) and a removal efficiency (97.4%, at 500mgL-1) for CR, and also display excellent selective adsorption in both single-dye and dual-dye systems. This method offers a rational strategy for synthesizing novel CDs-based adsorbents for CR, which provides a demonstration for future dye adsorption studies and practical wastewater treatment applications of CDs.

Synthesis of PBT-derived metal–organic frameworks as adsorbents for water treatment

Metal–organic frameworks (MOFs) have attracted significant interest as advanced molecular-separation materials with application prospects in gas separation, gas storage, solid catalysts, drug delivery systems, and water treatment. Among them, MIL-53(Al) and UiO-66(Zr) frameworks can be synthesized by numerous methods using polyethylene terephthalate (PET) as the starting material, and this promotes the recycling rate of PET. However, poly(butylene terephthalate) (PBT), which is a widely utilized disposable one-way engineering plastic in construction and automotive industries, can also be deployed as a starting material to promote recycling. Thus, in this study, the one-pot synthesis of MIL-53(Al) and UiO-66(Zr) was explored using PBT as the starting material. The results revealed that the obtained PBT-derived MOFs exhibited high crystallinity that was comparable to those of the 1,4-benzenedicarboxylate (BDC) reagent-derived MOFs even when glass fiber–blended PBT was used. Thereafter, the high crystallinity PBT-derived MIL-53(Al) and UiO-66(Zr) were deployed as liquid-phase adsorbents for removing metronidazole and benzophenone-4, which are significant constituents of recently reported water contaminants, respectively, demonstrating high adsorption performance, similar to those of BDC reagent-derived MOFs. Additionally, their adsorption isotherms followed the Langmuir model, indicating that the inner parts of their micropores acted as adsorption sites. Thus, the one-step facile synthesis of high crystallinity, high-purity PBT-derived MIL-53(Al) and UiO-66(Zr) is reported for the first time.

Efficient and fast arsenate removal from water by in-situ formed magnesium hydroxide

MgO nanoparticles have good As-adsorption capacity in treating As-contaminated wastewater but suffer from high production cost. In this study, instead of using pre-formed MgO nanoparticles, we found that in-situ formed Mg(OH)2 from MgCl2 and NaOH reaction exhibited super high arsenate (As(V)) removal efficiency. Only 1.5 mmol/L of in-situ formed Mg(OH)2 could remove more than 95% As(V) within 10 min to make the As contaminated water (10 mg-As(V)/L) meet the municipal wastewater treatment standard, whereas MgO nanoparticles failed. The Mg-As sludge has an amorphous crystal structure while no Mg(OH)2 phase could be observed. As(V) existed uniformly within the sludge which was confirmed by elemental mapping. A precipitation-adsorption-coagulation mechanism might exist, which could relieve the restriction of limited surface area of solid MgO adsorbents. This study not only reveals an applicable method for efficient removal of trace level As(V) from water but also implies the huge potential of in-situ formed adsorbents in water treatment.

Insight into the impact of environmental factors on heavy metal adsorption by sodium alginate hydrogel: Inspiration on applicable scenarios

Sodium alginate (SA) emerges as a promising adsorbent for the remediation of heavy metal-polluted wastewater. However, the systematic investigations on how and the extent to which the various compositions in real water matrices impact its performance were essential but rare when considering its use. Here, we explored the effect of common environmental factors on Cu(II) adsorption by an as-synthesized SA-based hydrogel (SAH). The result showed that high concentration of organics (above 10 mg L−1) had a negative influence on heavy metal removal (decreased by 9.45 % at least), while inorganic ion, turbidity and antibiotics at relatively low concentrations exhibited a negligible even promoting effect (increased by 9.8 % with the presence of 5 mg L−1 Nor). Based on above results and corresponding mechanism analyses, the possible applicable and unsuitable scenarios of SAH can be predicted. SAH could be a great candidate for treating heavy metal-polluted water such as river and lake water, while it is not a good option for electroplating or livestock wastewater which contains high concentration of organic matters. Besides, the operating conditions including pH (5.0 for Cu(II), 6.0 for Ni(II)), contact time (24 h), temperature (298 K) et al. were also determined. Overall, this work provides theoretical guidance and operational strategies for promoting the practical application of SA adsorbent in water treatment.

Comparative Assessment of Short-Chain PFAS Removal Using MIP-202: An Eco-Friendly, High-Performance, Fast-Recoverable, and Economic Adsorbent for Water Treatment

Comparative Assessment of Short-Chain PFAS Removal Using MIP-202: An Eco-Friendly, High-Performance, Fast-Recoverable, and Economic Adsorbent for Water Treatment

Green carbon-based adsorbents for water treatment in Sub-Saharan Africa

Abstract As underlined by the United Nations Sustainable Development Goals (UN SDGs), providing safe and clean potable water remains a significant concern in developing regions of the world, especially Sub-Saharan Africa. Extensive research has been done on this subject in Africa. The concept of sustainable chemistry towards solving another pressing issue in Africa – waste management – led to the decision to investigate green carbon-based materials for water purification on the continent. The conversion of “waste to wealth” is a practical means of achieving proper waste management at a reasonable cost. Low-cost adsorbents such as biochar, activated carbons, graphene and carbon composites, with high surface area, porosity and efficiency have been generated from agricultural waste and biomass, carbon-rich geological materials, carbonaceous polymeric materials, and hydrocarbons/petroleum by-products, using simple thermal and/or green chemical reaction protocols. Several drawbacks have hindered the development and utilization of adsorbents for the treatment of polluted water, including chemical fouling, loss of activity, poor reusability, difficulty associated with sorbent regeneration, production of secondary pollutants, toxicities caused by exposure to sorbent residues, and inability to deal with heavily polluted water. However, the use of adsorbents is still widely acclaimed as an efficient and cleaner method among other existing water treatment options such as extraction, chemical oxidation, bioremediation, and photocatalytic degradation. This paper outlines the research carried out by Sub-Saharan African scientists to proffer solutions to water pollution using green carbon-based adsorbents and discusses the breakthroughs, challenges, and future prospects.

Synthesis of eco-friendly bio-based coconut shell magnetic biochar for efficient bisphenol S sequestration in aqueous environment: green technology breakthrough

Water pollution has emerged as a critical global challenge, particularly the contamination of water bodies with persistent organic pollutants such as Bisphenol S (BPS), a known endocrine disruptor. This study presents the synthesis and application of eco-friendly bio-based coconut shell magnetic biochar (CSMB) for efficient sequestration of BPS from aqueous environments. Utilizing pyrolysis and co-precipitation techniques, the magnetic biochar was characterized through various methods including surface chemistry (pHpzc), electron dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) N2 adsorption-desorption, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). SEM revealed a porous structure with a high surface area, while FTIR confirmed the presence of functional groups essential for adsorption. X-ray diffraction (XRD) and VSM successfully incorporated magnetic nanoparticles, enhancing the separation process post-adsorption. The CSMB demonstrated a significant surface area of 373 m2 g−1, outperforming regular coconut shell biochar (CSB), with a BPS adsorption capacity of 43.5 mg/g compared to 26.7 mg/g for CSB. Batch adsorption tests assessed the impact of operational factors such as initial BPS concentration (8–150 ppm), contact time (30–150 min), temperature (298.15, 318.15, and 338.15 K), pH (3–11), and CSMB dosage (0.1–0.9 g). The results indicated optimal adsorption at pH 6 with a maximum capacity of 52.3 mg/g. Kinetic studies revealed that the pseudo-second-order model best described the adsorption process, while the Langmuir isotherm model provided an excellent fit for the adsorption data. The reusability of CSMB was validated over five cycles, with adsorption capacity decreasing slightly from 43.5 mg/g to approximately 41 mg/g, making it a sustainable and effective adsorbent for water treatment.

Insights into role of microstructure in TNT adsorption performances onto zeolite, diatomite and kaolinite particles

Adsorption performances of one pollutant on different adsorbents likely depend on the adsorbent microstructures heavily. Hereon, zeolite, diatomite and kaolinite particles were selected as inexpensive adsorbents in this study with 2,4,6-trinitrotoluene (TNT) as an organic pollutant for the batch test to verify the effect of adsorbent microstructure on TNT adsorption performance. The results of kinetic, adsorption isothermic, and thermodynamic analyses indicated that the adsorption process of TNT on three particles is controlled by chemisorption, and that both are non-spontaneous entropic endothermic reactions, although they have their own specific adsorption capacities, equilibration times, and kinetic rates. Comprehensively analyzing the characterization data and adsorption performances of the particles shows that, the pore physical properties including the pore diameter distribution and volume obviously control the adsorption capacities, and well the pore surface chemical properties such as the functional groups affect the adsorption kinetics; the microstructure affects the performances through the synergistic effect of physical and chemical pathways and results in the special performances. Briefly, a particle has its special microstructure and then determinedly unique performance. The finding provides insights into the role of the microstructure of the particles in their performances, and significances for selecting and utilizing the adsorbents in water treatment.

Hybrid chitosan/HKUST-1 hydrogel with freezing and thawing modification as sustainable porous material for removal and selective separation of dye mixtures

A hybrid chitosan monolithic hydrogel (CS) was modified by incorporating with HKUST-1 and fabricated using an in-situ growth method. The resulting hydrogel CS/HKUST-1 was further modified to enhance the porous structure, in which the porous converted from close pores to interconnected porous structures. The chemical and physical characteristics of the modified hydrogel were examined using various characterization techniques like BET, SEM, EDX, FTIR, XRD, Zeta potential, and compression test to understand the effect of the modification. The outcomes displayed that this method provided homogeneous dispersing of HKUST-1 crystals within the chitosan hydrogel matrix, which can improve the material's specific surface area and adsorption capacity. The CS/HKUST-1 monolithic hybrid hydrogel's permeability is further enhanced by the freezing and thawing process and the produced hydrogel is called FCS/HKUST-1, which helps to open the hydrogel's pores and significantly increases its surface area. FCS/HKUST-1 hydrogels display higher mechanical properties without fracture after compression with elastic properties, whereas the CS/HKUST-1 hydrogel crashed at around 47 % compression strain. Consequently, the obtaining dual modified chitosan/ HKUST-1 hydrogel (FCS/HKUST-1) was evaluated as an adsorbent to eliminate Eosin Y (EY) dye from its aqueous solution and the adsorption mechanism was proposed as multilayer adsorption depending on the Freundlich isotherm model. The modified monolithic hydrogel displayed an excellent maximum adsorption capacity with EY dye about 625 mg·g−1. The FCS/HKUST-1 hydrogel showed extremely selective removal for anionic dye higher than cationic dye, which allows facile separation of the dyes with different charges in a mixture solution. The outcomes also demonstrate that the modified hydrogel would be an eco-friendly material, which shows excellent recyclability, indicating that this material considerable promising adsorbent in water treatment.

Characterization and application of LDH with chitosan composites investigated by positron annihilation lifetime spectroscopy and surface texture for the adsorption of methyl orange

With a rapid increase in industrial growth around the world, the demand for an entirely novel category of nanoparticles and technologies for wastewater treatment has become a key concern for environmental protection. Recently, hybrids of layered double hydroxides (LDH), particularly those containing LDH, have gained attention as potential nanoscale adsorbents for water treatment. Recent research has shown that LDH-containing composites are interesting versatile materials with the ability to be used in energy storage, photocatalysis, nanocomposites, and water treatment. In the current work, LDH-containing composites were utilized as adsorbents for the purpose of purifying water. The adsorbents investigated are Zn–Co–Fe/LDH/Chitosan-in situ sample preparation (LDH/CS1) and Zn–Co–Fe/LDH/Chitosan-ex situ sample preparation (LDH/CS2). Furthermore, LDH/CS1 and LDH/CS2 were investigated for wastewater treatment from methyl orange dye (MO) with various adsorption conditions. When the initial MO concentration was 20 mg/L and the amount of adsorbent was 0.1 g, the removal efficiency reached 72.8 and 91.7% for LDH/CS1 and LDH/CS2, respectively. The MO’s maximum adsorption capabilities are 160.78 and 165.89 mg/g for LDH/CS1 and LDH/CS2, respectively, which is much greater than that of comparable commercial adsorbents. MO adsorption onto LDH/CS1 and LDH/CS2 was best characterized by the pseudo-second-order kinetic model. The equilibrium adsorption data was followed by the Freundlich and Langmuir models. The adsorption is favorable as evidenced by the equilibrium parameter RL values for MO adsorption onto LDH/CS1 and LDH/CS2, which were 0.227 and 0.144, respectively. Using the free volume distribution method and the positron annihilation lifetime technique, the nanostructure of the materials was examined.

Ultra-high selective removal of Congo red and Ciprofloxacin using unusual LDO modified biochar: Influence of emerging pollutants and application attempts

The porous biochar materials serve as effective adsorbents in water treatment. In this study, layered-double-hydroxide (LDH)(MgAl) was dispersed onto waste poplar powder through the co-precipitation method, followed by pyrolysis to prepare layered-double-oxides (LDO)/poplar carbon (CL-800) for ultra-high adsorption of Congo red (CR) and Ciprofloxacin (CIP). The CL-800 adsorbent possessed a well-developed layered porous structure that provides numerous adsorption sites and transport channels for dyes and antibiotics. Notably, CL-800 exhibited a significantly elevated level of selectivity and adsorption capacity towards CR and CIP reaching 93.0, 84.7 % and 4841.2, 744.0 mg/g, respectively. Various factors were considered to investigate the influence on CR and CIP adsorption, such as ion types, microplastics, and perfluorooctanoic acid. The adsorption capacity in complex water systems were also explored where CL-800 presented excellent removal efficiencies for CR (99.0 %) and CIP (89.6 %) in simulated wastewater along with good repeatability. Fixed-bed column tests also confirmed its potential as an effective adsorbent for wastewater purification due to continuous adsorption properties towards CR and CIP over time. Finally, the interaction mechanisms for CR/CIP adsorption processes onto CL-800 were possibly determined via various advanced techniques. This study provides new perspectives for providing a potential low-cost efficient adsorbent for organic wastewater treatment.

Utilizing magnetic nanoparticles embedded into polyvinyl alcohol and sodium alginate for the absorption of arsenic

Arsenic is an extremely toxic metalloid. The majority of arsenic water pollution originates from industrial activities such as mining, smelting, and utilization of arsenic compounds in glass, pigment, semiconductor, and other industries. Arsenic-containing wastewater poses a threat to groundwater, freshwater, seawater, and soil. Bioaccumulation of arsenic as a result of accidental ingestion may have a harmful effect on the skin and cardiovascular, respiratory, and nervous systems, thereby posing a major health risk. Chemical coagulation, membrane filtration, and adsorption can be used to treat arsenic-containing wastewater. However, chemical coagulation produces a large amount of waste sludge, which is harmful and incurs high processing costs. Membrane filtration is difficult to adopt because of its high operation and maintenance costs. Adsorption is an inexpensive, easy-to-use, sludge-free water treatment method that enables adsorbent recycling. These characteristics make adsorption an economically feasible technique for water treatment. Magnetic nanoparticles (MNPs) are small particles with a high surface area to volume ratio. Their strong magnetic properties enable them to absorb specific water pollutants. MNPs are currently used as water treatment adsorbents. However, they have several drawbacks, including low acid and alkali buffer capacity and water oxidation. In this study, MNPs immobilized with polyvinyl alcohol (PVA) and sodium alginate (SA) were used to enhance the efficacy of wastewater treatment with magnetic materials. These modified MNPs exhibited magnetic characteristics and improved acid resistance. When 100 g/L PVA/SA-MNPs (pH 1–6) were stirred at 120 rpm for 30 min, the resulting iron concentration of the water was 16 mg/L. By contrast, the MNPs released iron in levels ranging from 18 to 4045 mg/L. The PVA/SA–MNPs efficiently adsorbed arsenic in the pH range 3–6, with a high removal efficiency of 76%–82%. At pH 5, the average adsorption capacity was 382 ± 27 μg/g. To recover the MNPs, they were rinsed with deionized water and immersed in acid three times, after which their adsorption capacity was 300 μg/g or higher. By contrast, the PVA/SA-MNPs could be recovered through spontaneous sedimentation, eliminating the need for a magnetic field and simplifying the collection process. In addition, iron dissolution in acidic solutions was minimized for the PVA/SA-MNPs, contributing to environmental protection.

Salsola Tetragona as a new low-cost adsorbent for water treatment: highly effective adsorption of crystal violet

Synthetic dyes are prevalent in aquatic environments, they have high toxicities, are non-degradable, and accumulate in the water. The removal of Crystal violet (CV) is carried out using batch experiments on the Salsola Tetragona (ST) plant as a novel adsorbent. The prepared adsorbent was analyzed by various methods (MEB, EDX, IRTF and PZC), to support its applicability as adsorbent. The adsorption study of CV is performed by optimizing the parameters affecting the adsorption process. The adsorption kinetics study is represented by pseudo-second-order (R2 = 0.999) and the adsorption process is limited by external mass transport. In addition, the isotherm results demonstrate that the Langmuir model interprets better the adsorption isotherm. The thermodynamic parameters suggest that the adsorption phenomena are spontaneous and exothermic. Furthermore, the adsorption reactions involved are of physisorption type, which facilitates the desorption of pollutants from the surface of the adsorbent. The results show that ST adsorbent effectively removes CV in an aqueous solution, which is demonstrated by the maximum amount adsorption of 246.7 mg.g−1 at optimum adsorption conditions: pH = 6, adsorbent dose of 0.5 g.L−1, initial CV concentration of 10 mg.L−1, and adsorption time of 30 min at 298 K. Finally, these results can be considered as a useful reference for wastewater treatment using ST.

Activated carbon and their nanocomposites derived from vegetable and fruit residues for water treatment

Water pollution remains a pressing environmental issue, with diverse pollutants such as heavy metals, pharmaceuticals, dyes, and aromatic hydrocarbon compounds posing a significant threat to clean water access. Historically, biomass-derived activated carbons (ACs) have served as effective adsorbents for water treatment, owing to their inherent porosity and expansive surface area. Nanocomposites have emerged as a means to enhance the absorption properties of ACs, surpassing conventional AC performance. Biomass-based activated carbon nanocomposites (ACNCs) hold promise due to their high surface area and cost-effectiveness. This review explores recent advancements in biomass-based ACNCs, emphasizing their remarkable adsorption efficiencies and paving the way for future research in developing efficient and affordable ACNCs. Leveraging real-time communication for ACNC applications presents a viable approach to addressing cost concerns.

Theoretical and Experimental Analysis of Hydroxyl and Epoxy Group Effects on Graphene Oxide Properties.

In this study, we analyzed the impact of hydroxyl and epoxy groups on the properties of graphene oxide (GO) for the adsorption of methylene blue (MB) dye from water, addressing the urgent need for effective water purification methods due to industrial pollution. Employing a dual approach, we integrated experimental techniques with theoretical modeling via density functional theory (DFT) to examine the atomic structure of GO and its adsorption capabilities. The methodology encompasses a series of experiments to evaluate the performance of GO in MB dye adsorption under different conditions, including differences in pH, dye concentration, reaction temperature, and contact time, providing a comprehensive view of its effectiveness. Theoretical DFT calculations provide insights into how hydroxyl and epoxy modifications alter the electronic properties of GO, improving adsorption efficiency. The results demonstrate a significant improvement in the dye adsorption capacity of GO, attributed to the interaction between the functional groups and MB molecules. This study not only confirms the potential of GO as a superior adsorbent for water treatment, but also contributes to the optimization of GO-based materials for environmental remediation, highlighting the synergy between experimental observations and theoretical predictions in advances in materials science to improve sustainability.

Efficient removal of tetracycline and Cu2+ by honeycomb derived magnetic carbon: Adsorption mechanism and advanced oxidation regeneration mechanism

The honeycomb magnetic carbons (xFe@HCNs) were prepared by sacrificial template method novelty using polyacrylamide resin (PAAS) as template and ammonium pyrrolidine dithioate/Fe3+ complex (APDC-Fe) as carbon skeleton and metal source. Tetracycline (TC) and copper (Cu2+) as target pollutants were used to investigate the adsorption properties of xFe@HCNs in single or binary TC and Cu2+ systems. The adsorption capacity sequence for TC among the adsorbents was (mmol·g−1): 2Fe@HCNs (0.088) > 8Fe@HCNs (0.061) > HCNs (0.054) > RC (0.036), and for Cu2+ was (mmol·g−1): 2Fe@HCNs (1.120) > 8Fe@HCNs (1.026) > RC (0.792) > HCNs (0.681). 2Fe@HCNs demonstrated notable affinity for adsorbing both TC and Cu2+. Additionally, the influence of hydrochemical factors (i.e., cation species, anion species, and pH) on the adsorption properties of 2Fe@HCNs. Combined with advanced oxidation technology, the regeneration methods of magnetic adsorbent were explored using oxidizing agents (e.g., H2O2 and peroxymonosulfate) as eluents which could increase the adsorption sites of magnetic carbon adsorbents during the regenerating process, which was the novelty of the study. Furthermore, the regeneration mechanisms of H2O2 as eluent were investigated. This study discussed the application and regeneration methods of magnetic adsorbents in water treatment, offering new insights into environmental remediation using magnetic materials.