Enhanced Adsorption of Bisphenol A from Aqueous Solution with 2-Vinylpyridine Functionalized Magnetic Nanoparticles

A two-stage Fe(VI) oxidation process enhances the removal of bisphenol A for potential application

Ferrate (Fe(VI)) has been extensively studied as a green oxidant to treat wastewater. But Fe(VI) oxidation still faces several challenges for application, such as the sensitivity of Fe(VI) to pH and the restrictions on the Fe(VI) utilization efficiency for pollutant elimination at low concentration levels. This study proposed a two-stage Fe(VI) oxidation process to enhance the bisphenol A (BPA) removal for potential applicability, consisting of the adsorption by CNTs of stage I and the degradation by Fe(VI) of stage II. The Fe(VI) utilization efficiency in the two-stage process (0.848) was higher than that in one-stage processes (0.727) and Fe(VI) alone system (0.504) at pH 9. In stage I, the adsorption process had good compliance with the Langmuir isotherm model and pseudo-second-order kinetic model. In stage II, the effective utilization of low-concentration Fe(VI) was 2.45 times more than Fe(VI) alone, and the reduction of reaction volume was beneficial to further enhance utilization. The probe experiments (sulfoxide) and the degradation experiments of other electron-donating/withdrawing pollutants (e.g., atrazine, benzoic acid) demonstrated that Fe(IV) and Fe(V) were major oxidizing species in the two-stage process. The regeneration experiments showed that CNTs still had acceptable adsorption and catalytic capabilities after five cycles. Finally, the intermediate products in the two-stage process were detected and four possible degradation pathways of BPA were proposed. These findings were meaningful for the practical application of Fe(VI) oxidation to overcome the conditional limitation and improve the utilization.

The efficient adsorption of tetracycline from aqueous solutions onto polymers with different N-vinylpyrrolidone contents: equilibrium, kinetic and dynamic adsorption

Extensive use of antibiotics in the world will cause potential risks to human health and ecosystems. The removal of these antibiotics has attracted much attention. Composite materials are growing attention for diverse pollutants separation and removal based on their specific functionality and surface area. In this study, a series of N-vinylpyrrolidone-divinylbenzene polymers (NVPD) with different N-vinylpyrrolidone (NVP) contents were facilely prepared for the adsorption of tetracycline (TC). The effect of polymer surface properties and aqueous solution chemistry (pH, ionic strength, humic acid) on TC adsorption was further studied. The dynamic adsorption and regeneration experiments were also assessed. The results showed that only 25% of NVP was involved in the reaction. When NVP dosage (%) was 75%, polymer (NVPD-g) owned the largest BET surface area (613.23 m2/g) and obtained the maximum TC adsorption capacities (258.76 mg/g). In the kinetic, the adsorption between TC and polymers with NVP was controlled by chemical adsorption and intra-particle diffusion. The TC adsorption process of NVPD-g depended on the contribution of the hydrophobic effect, electrostatic interactions, H-bonding, π-π electron donor-acceptor (EDA) interactions, and cation-π bonding. Moreover, the removal efficiency of TC by NVPD-g was enhanced in the presence of humic acid (HA) in the dynamic adsorption and 1197 BV (2394 mL) of TC simulated wastewater can be treated. These findings suggest that NVPD-g has a potential application in the purification of TC.

Current progress in treatment technologies for plastic waste (bisphenol A) in aquatic environment: Occurrence, toxicity and remediation mechanisms

Bisphenol-A (BPA) is a type of endocrine disrupting compound (EDC) that is being widely used in the production of polycarbonate and epoxy resins. In the last few years, human exposure to BPA has been extensively high due to the continuous increment in the Annual Growth Rate (AGR) of the BPA global market. The presence and transportation of BPA in the environment could cause serious damage to aquatic life and human health. This paper reviewed the literature on the exposure and toxicity mechanisms of BPA and advanced analytical techniques for the detection of BPA in the environment and human beings. The study indicated that BPA can cause damaging effects on numerous tissues and organs, including the reproductive system, metabolic dysfunction, respiratory system, immune system and central nervous system. On the basis of reported studies on animals, it appears that the exposure of BPA can be carcinogenic and responsible for causing a variety of cancers like ovarian cancer, uterine cancer, prostate cancer, testicular cancer, and liver cancer. This review paper focused mainly on the current progress in BPA removal technologies within last ten years (2012-2022). This paper presents a comprehensive overview of individual removal technologies, including adsorption, photocatalysis/photodegradation, ozonation/advance oxidation, photo-fenton, membranes/nanofilters, and biodegradation, along with removal mechanisms. The extensive literature study shows that each technology has its own removal mechanism and their respective limitations in BPA treatment. In adsorption and membrane separation process, most of BPA has been treated by electrostatic interaction, hydrogen boning and π-π interations mechanism. Whereas in the degradation mechanism, O* and OH* species have played a major role in BPA removal. Some factors could alter the removal potential and efficiency of BPA removal. This review paper will provide a useful guide in providing directions for future investigation to address the problem of BPA-containing wastewater treatment.

Impregnation of Silver Nanoparticles onto Polymers Based on Sugarcane Bagasse for the Remediation of Endocrine Disruptor–Bisphenol A from Water

This present study introduces a contemporary innovation of synthesized polymer–silver nanoparticle nanocomposite adsorbent based on sugarcane bagasse (AgNP-SB-βCD) for the sequestration of emerging micropollutant–bisphenol A from water matrix. Batch adsorption mode was carried out to assess the effectiveness of AgNP-SB-βCD nanocomposites towards eliminating bisphenol A (BPA). Characterization techniques including SEM, FTIR, and XRD have confirmed the successful incorporation of silver nanoparticles (AgNPs) onto bagasse–polymer. At 25°C, pH 7, and contact time of 120 min, the nanocomposites had a maximum uptake capacity of 158.4 mg g-1on BPA. The equilibrium isotherm of BPA on AgNPs-SB-βCD has fitted effectively with Langmuir model while the adsorption kinetics conformed to pseudo-second order. The adsorption phenomenon was controlled mainly by physisorption (via host–guest inclusion van der Waals bonding and pore filling effect). In addition, oxidative degradation of BPA by AgNPs-SB-βCD could marginally contribute the removal of BPA due to oxidative dissolution of AgNPs at pH 7. The thermodynamic results substantiate the spontaneity and exothermic behaviors of the adsorption phenomenon. The polymeric nanocomposite adsorbent was regenerated five times (using 75% ethanol) without considerable loss of its adsorption capacity. This authenticates its reusability and consistency performances; accordingly, it can be a market competitor adsorbent for the treatment of water contaminated with BPA.

The efficient removal of bisphenol A from aqueous solution using an assembled nanocomposite of zero-valent iron nanoparticles/graphene oxide/copper: Adsorption isotherms, kinetic, and thermodynamic studies

In this study, nanoparticles of zero-valent iron (nZVI) along with graphene oxide (GO) and copper (Cu) was synthesized to apply as a promising adsorbent for the rapid removal of bisphenol A (BPA) from aqueous solution. The characteristics of nZVI-GO-Cu were analyzed by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), and vibrating sample magnetometer (VSM). The average particle size of nZVI-GO-Cu was found to be 20.89 nm. The effective experimental variables such as pH, adsorbent dosage, contact time, initial BPA concentration, and temperature were surveyed to assess optimum conditions. Results revealed that the maximum removal percentage was obtained at pH of 7, adsorbent dosage of 0.2 g, contact time of 10 min, the BPA concentration of 10 mg/L, and a temperature of 35 °C as optimum conditions. Experimental data were fitted to the Langmuir and pseudo second-order models with a coefficient of determination (R²) equal to 1 and 0.995, respectively. The obtained maximum adsorption capacity (q_max) of the Langmuir isotherm was 21.59 mg g^-1. Thermodynamic parameters under the various temperatures confirmed that the adsorption process was endothermic (ΔH = 17,459.4 J/mol and ΔS = 61.23 J/mol/K) and spontaneous (ΔG < 0). As a conclusion, nZVI-GO-Cu can be selected as an efficient adsorbent for the treatment of aqueous media from BPA and the other pollutants, due to its low-cost, high removal efficiency (97%), and rapid adsorption with the minimum time of 10 min compared with the other adsorbents.

Low-Cost Synthesis of Alumina Nanoparticles and Their Usage for Bisphenol-A Removal from Aqueous Solutions

Gamma-alumina nanoparticles (γANPs) were obtained from a low-cost process by using natural bauxites. The γANPs materials were characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, scanning electron microscopy (SEM), atomic force microscopy (AFM), and were functionalized with N-cetyl-N, N, N, trimethylammonium bromide (CTAB), leading to CTAB modified γ-alumina nanoparticles (γANPs-CTAB). These novel functionalized γANPs-CTAB were characterized by XRPD, FTIR, and were used as an adsorbent for bisphenol-A (BPA) removal from water. Batch investigations were conducted under different experimental conditions (e.g., adsorbent dose, agitation time, initial concentration, and pH and surfactant loading) in order to optimize BPA adsorption and to identify the adsorption mechanisms in the system γANPs-CTAB-BPA. The effect of pH on the adsorption showed that the quantity of BPA removed increased remarkably until the pH value was 4, then remained almost constant until the pH value was up to 10, and then decreased for pH values greater than 10. For an initial BPA concentration of 20 mg/L and an adsorbent dose of 12.5 g/L at a pH value of 10, the removal efficiency achieved was 91.80 ± 0.21%. The adsorption mechanism was perfectly described by pseudo-second-order kinetics and the Langmuir isotherm. γANPs-CTAB materials were found to be effective adsorbents for BPA removal from water.

Adsorption performance of modified agricultural waste materials for removal of emerging micro-contaminant bisphenol A: A comprehensive review

This review is an attempt to assess the adsorption performance of different green adsorbents derived from agricultural waste materials (AWMs) that were used for the elimination of bisphenol A (BPA) from aqueous matrices. Different processes including grafting, polymerization, activation and chemical treatment have been applied to functionalize and modify agricultural waste materials for the purposes of increasing their adsorptive performances toward BPA. The highest reported adsorption capacity of adsorbent from agricultural waste for the uptake of BPA is the highly microporous carbon adsorbent derived from Argan nut shell (1408 mg g^-1). Hydrogen bonding, hydrophobic and π-π interactions were reported in most studies as the main mechanisms governing the adsorption of BPA onto agricultural waste adsorbents. Equilibrium isotherm and kinetic studies for the uptake of BPA onto agricultural waste adsorbents were best described by Langmuir/Freundlich model and pseudo-second order model, respectively. Despite the effective elimination of BPA by various agricultural waste adsorbents, an appropriate selection of elution solvent is important for effective desorption of BPA from spent adsorbent. To date, ethanol, diethyl ether-methanol, methanol-acetic acid, mineral acids and sodium hydroxide are the most eluents applied for desorption of BPA molecules loaded onto AW-adsorbents. Looking toward the future, studies on the agricultural waste adsorbents based on polymers, activated carbons, nanoparticles and highly microporous carbons should be mostly considered by the researchers toward removing BPA. These future studies should be performed both in laboratory, pilot and industrial scales, and also should report the sustainable techniques for disposal of the spent AW-adsorbents after lose their adsorption performance on BPA.

A molecularly imprinted polymer on chromium (ΙΙΙ) oxide nanoparticles for spectrofluorometric detection of bisphenol A

A unique fluorescent probe for the detection of bisphenol A (BPA) was established by creating a molecularly imprinted polymer (MIP) shell on chromium (ΙΙΙ) oxide nanoparticles (Cr₂O₃ NPs). The advantages of high selectivity of MIPs and the strong fluorescence property of Cr₂O₃ NPs were combined for the preparation of the probe. MIPs-coated Cr₂O₃ NPs were composed by anchoring MIP layer on the surface of Cr₂O₃ NPs using one-pot precipitation polymerization. Acrylic-based monomer and cross-linker were used to prepared MIP. The MIP-coated Cr₂O₃ NPs were characterized by spectrofluorometery, Fourier transform infrared spectroscopy, transmission electron microscopy, field transmission electron microscopy, dynamic light scattering, EDX and elemental mapping. The prepared NPs showed strong fluorescence emission at 360 nm excited at 300 nm which quenched in the presence of BPA. The dynamic range of the optical sensor was in the range of 0.04-4.4 μmol L^-1 and the detection limit was 0.015 μmol L^-1. The relative standard deviation was 2.2 and 1.3% for the concentration levels of 0.14 and 3.1 μmol L^-1, respectively. The probe had a great selectivity in the determination of BPA with an imprinting factor of 6.3. The sensor was applied for the quantification of bisphenol A in water samples.

Study on the adsorption and desorption performance of magnetic resin for Congo red

This study was to evaluate the adsorption capability of a magnetic resin (NDMP) to the removal of Congo red (CR) from aqueous solution. The adsorption kinetic and isotherm of NDMP were studied, as well as the desorption performance of NDMP. The results showed that the adsorption process of NDMP on CR was more suitable for Pseudo-second-order kinetic model. The whole adsorption process was affected by intraparticle diffusion and ion exchange. The adsorption isotherm of CR by NDMP was fitted better with Langmuir model. It showed that the adsorption of CR on NDMP resin was single layer adsorption. The maximum adsorption capacity (Q_m) of CR at 308 K can reach 354.29 mg/g. In the desorption, 10% NaCl and NaOH eluents had better desorption rate for CR than other mass fraction. While NaCl(10%)-MeOH mixed eluent with volume ratio of 3:7 had the best regeneration performance. The desorption rate can reach 90% within 30 min. The adsorption performance of NDMP on CR didn't decrease after 13 times successive adsorption-desorption by NaCl(10%)-methanol eluent, indicating that NDMP can be efficiently regenerated. The excellent adsorption-desorption performance of NDMP on CR suggests that the magnetic resin has a great potential for treating CR dye wastewater.

Removal of bisphenol A from aqueous media using a highly selective adsorbent of hybridization cyclodextrin with magnetic molecularly imprinted polymer

In this study, a unique magnetic molecularly imprinted polymer (MMIP) adsorbent towards bisphenol A (BPA) as a template molecule was developed by bulk polymerization using β-cyclodextrin (β-CD) as a co-monomer with methacrylic acid (MAA) to form MMIP MAA-βCD as a new adsorbent. β-CD was hybridized with MAA to obtain water-compactible imprinting sites for the effective removal of BPA from aqueous samples. Benzoyl peroxide and trimethylolpropane trimethacrylate were used as the initiator and cross-linker, respectively. The adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, vibrating sample magnetometer, Brunauer-Emmett-Teller and X-ray diffraction. 1H nuclear magnetic resonance spectroscopy was used to characterize the MAA-βCD and BPA-MAA-βCD complex. Several parameters influencing the adsorption efficiency of BPA such as adsorbent dosage, pH of sample solution, contact time, initial concentrations and temperature as well as selectivity and reusability study have been evaluated. MMIP MAA-βCD showed significantly higher removal efficiency and selective binding capacity towards BPA compared to MMIP MAA owing to its unique morphology with the presence of β-CD. The kinetics data can be well described by the pseudo second-order kinetic and Freundlich isotherm and Halsey models best fitted the isotherm data. The thermodynamic studies indicated that the adsorption reaction was a spontaneous and exothermic process. Therefore, MMIP based on the hybrid monomer of MAA-βCD shows good potential of a new monomer in molecularly imprinted polymer preparation and can be used as an effective adsorbent for the removal of BPA from aqueous solutions.

Magnetite doped metal–organic framework nanocomposites: an efficient adsorbent for removal of bisphenol-A pollutant

The removal of bisphenol-A (BPA) from the aqueous environment is a vital issue for public health due to its toxic effect.

Bio-sorption of bisphenol a by the dried- and inactivated-lichen (Pseudoevernia furfuracea) biomass from aqueous solutions

Bisphenol A (BPA), which is known as one of the endocrine-disrupting chemicals (EDCs) with hydrophilic hydroxyl groups and hydrophobic aromatic groups, has been widely used in plastic industries. The chemical waste from the industry is sometimes discharges into lakes and rivers, and then these surface waters can be polluted. So, this article aims to investigate the bio-sorption process of BPA by the inactivated lichen (Pseudoevernia furfuracea) biomass from aqueous solution. At initial, the effect of the variables such as initial BPA concentration, solution pH, temperature, contact time and recovery rate on the bio-sorption process was investigated. From the optimal results, it has been observed that the highest removal efficiency is approximately 64% at a contact time of 3-h, the bio-sorbent concentration of 9 mg/L, initial BPA concentration of 40 mg/L, and agitation speed of 150 rpm at pH 5.0. In explaining the bio-sorption potential of lichen biomass, Langmuir and/or Redlich-Peterson isotherms with two and three parameters, respectively were observed to be better fit with the experimental isotherm data (R² = 0.982). From equilibrium data based on difference between the measured and predicted results (q_{e, exp} and q_{e, pre}), it was shown that biosorption of BPA could be best described by the pseudo second order kinetic model with minimum sum of square error of 2.61%. In addition, it shows more film diffusion, and partly pore diffusion in linearity region in terms of kinetic sorption behaviors of BPA in the rate-limiting step as well as intra-particle diffusion according to Boyd's kinetic model with better regression coefficient than 0.981 when compared to the other used kinetic models, including Bangham's pore diffusion and Elovich kinetic models (with R² of 0.958 and 0.929). The thermodynamic studies showed that the biosorption process was spontaneous, and chemically feasible. Therefore, due to be low-cost, eco-friendly character, wide availability and easily accessible, the lichen biomass could be used as a promising bio-sorbent for the removal of BPA from the environment and wastewater effluents.

Uptake of micropollutant-bisphenol A, methylene blue and neutral red onto a novel bagasse-β-cyclodextrin polymer by adsorption process

The presence of emerging micropollutants and dyes in water resource has raised global concern about their intense effects to aquatic environments, ecosystem and human health in general. So far, various adsorbents have been suggested for reducing the levels of bisphenol A, methylene blue and neutral red contamination in wastewaters. However, a number of these adsorbents seemed to have low adsorptive capacities and regeneration performances. In view of these, batch experiment was performed to decontaminate these pollutants from aqueous solutions using an optimized bagasse-β-cyclodextrin polymer (SB-β-CD). Characterization studies of SB-β-CD were performed using FTIR, pH point of zero charge, XRD and BET methods. Adsorption of BPA, MB and NR was favored at lower temperature (298 K) and pH of 7.0, 9.0 and 6.0, respectively. The maximum adsorption capacity of BPA, MB and NR at 298 K was 121, 963 and 685 mg g^-1, respectively. Hydrogen bonding through host-guest inclusion and electrostatic interactions could respectively attribute to uptake of BPA and MB/NR onto SB-β-CD. Adsorption kinetics of three pollutants followed pseudo-second-order model. Langmuir and Freundlich models were fitted to describe the adsorption of BPA and MB/NR, respectively. Thermodynamic parameters confirmed the occurrence of physical adsorption which is spontaneous and exothermic in nature. SB-β-CD loaded with BPA and MB/NR was certainly reused by 75% ethanol and 0.1 mol L^-1 HCl solutions, respectively. Novel SB-β-CD showed better adsorptive capacity and regeneration performances; consequently can offers practical application for removal of BPA, MB and NR from wastewaters.

Ion-Trap Mass Spectrometric Analysis of Bisphenol A Interactions With Titanium Dioxide Nanoparticles and Milk Proteins

Quantitative analysis of endocrine-disrupting molecules such as bisphenol A (BPA) in freshwater to determine their widespread occurrence in environmental resources has been challenged by various adsorption and desorption processes. In this work, ion trap mass spectrometry (ITMS) analysis of BPA was aimed at studying its molecular interactions with titanium dioxide (TiO2) nanoparticles and milk whey proteins. Addition of sodium formate prevented TiO2 nanoparticles from sedimentation while enhancing the electrospray ionization (ESI) efficiency to produce an abundance of [BPA + Na]+ ions at m/z 251.0. More importantly, the ESI-ITMS instrument could operate properly during a direct infusion of nanoparticles up to 500 μg/mL without clogging the intake capillary. Milk protein adsorption of BPA could decrease the [BPA + Na]+ peak intensity significantly unless the proteins were partially removed by curdling to produce whey, which allowed BPA desorption during ESI for quantitative analysis by ITMS.

Cross-linked chitosan/zeolite as a fixed-bed column for organic micropollutants removal from aqueous solution, optimization with RSM and artificial neural network

Organic micropollutants (MPs) in low concentrations can affect aquatic ecosystems and human health. Adsorption technique is one of the promising methods to remove MPs. Chitosan and zeolites are environmentally friendly and low-cost adsorbents. Thus, removal of organic MPs (such as bisphenol A (BPA), carbamazepine (CBZ), ketoprofen (KTF) and tonalide (TND) from aqueous solution via cross-linked chitosan/zeolite, as a fixed-bed column, was investigated in the current study. Hydraulic retention time was set at 0.8 h pH and concentration of organic MPs ranged from 4 to 8 and 0.50 mg/L to 2.0 mg/L, and they were considered as factors in optimizing the removal of pollutants via response surface methodology (RSM). Approximately 1.4560 mg/L (89.0%) of BPA, 1.4724 mg/L (90.0%) of CBZ, 1.4920 mg/L (91.2%) of KTF and 1.4118 mg/L (86.3%) of TND were removed at 5.1 pH and 1.636 mg/L initial concentration as the optimum removal efficiency on the basis of RSM. Artificial neural network (ANN) was used to optimise removal effectiveness for each MP. The high R² values and reasonable mean squared errors indicated that ANN optimized MP removal in a logical aspect. Adsorption isotherm studies revealed that organic MP removal through chitosan/zeolite could be explained with Freundlich and Langmuir isotherms.

Graphene Oxide Based Magnetic Nanocomposites with Polymers as Effective Bisphenol-A Nanoadsorbents

Magnetic graphene oxide was impregnated with polymers for the preparation of nanocomposite adsorbents to be examined for the adsorptive removal of a typical endocrine disruptor, bisphenol–A (BPA) from aqueous solutions. The polymers used were polystyrene, chitosan and polyaniline. The nanocomposites prepared were characterized for their structure, morphology and surface chemistry. The nanocomposites presented an increase adsorptive activity for BPA at ambient conditions, compared to pure magnetic oxide, attributed to the synergistic effect of the polymers and the magnetic graphene oxide. The increased adsorption of BPA exhibited by the nanocomposites with chitosan and polyaniline could be attributed to the contribution of amine groups.