Acetaminophen removal by calcium alginate/activated hydrochar composite beads: Batch and fixed-bed studies

Competitive adsorption of acetaminophen and caffeine onto activated Tingui biochar: characterization, modeling, and mechanisms

Tingui biochar (TB) activated with potassium hydroxide (TB-KOH) was synthesized in the present study. The adsorption capacity of TB-KOH was evaluated for the removal of acetaminophen and caffeine in monocomponent and bicomponent solutions. As a result, the study of the TB-KOH characterization as well as the adsorption kinetics, isotherm, thermodynamics, and a suggestion of the global adsorption mechanism are presented. TB-KOH was characterized through physical-chemical analysis to understand its surface morphology and how it contributes to the adsorption of these drugs. Furthermore, modelling using advanced statistical physical models was performed to describe how acetaminophen and caffeine molecules are adsorbed in the active sites of TB-KOH. Through the characterizations, it was observed that the activation with KOH contributed to the development of porosity and functional groups (-OH, C-O, and C = O) on the surface of TB. The monocomponent adsorption equilibrium was reached in 90 min with a maximum adsorption capacity of 424.7 and 350.8 mg g-1 for acetaminophen and caffeine, respectively. For the bicomponent solution adsorption, the maximum adsorption capacity was 199.4 and 297.5 mg g-1 for acetaminophen and caffeine, respectively. The isotherm data was best fitted to the Sips model, and the thermodynamic study indicated that acetaminophen removal was endothermic, while caffeine removal was exothermic. The mechanism of adsorption of acetaminophen and caffeine by TB-KOH was described by the involvement of hydrogen bonds and π-π interactions between the surface of TB-KOH and the molecules of the contaminants.

Novel activated carbon from Magonia pubescens bark: characterization and evaluation of adsorption efficiency

In this work, the synthesis of activated carbon from the bark of the Magonia pubescens (known as Tingui) and its efficiency in the removal of diclofenac sodium through batch adsorption tests and physical-chemical characterizations were investigated. The phytotoxicity of this material was also evaluated through germination and root growth of Lactuca sativa seeds. According to the experimental design performed for the synthesis of Tingui carbon, the optimized temperature and residence time for the production of this adsorbent were 550 °C and 120 min, respectively. The equilibrium time was reached in 600 min and the theoretical model that best fitted the kinetic data was the Elovich model. The BET was the best fit for the adsorption isotherm dataThis indicates that the adsorption process of sodium diclofenac by activated carbon can occur by two different mechanisms, monolayer and/or multilayer adsorption, depending on the conditions employed in the process, such as temperature and adsorbate concentration. The thermodynamic study showed that the process was favourable and spontaneous in the temperature range evaluated. Furthermore, the characterizations showed by TG/DTG and FTIR analyses that the temperature throughout the process had a marked impact on the degradation of the organic constituents of the biomass and the appearance of distinct functional groups that contributed to the adsorption process of diclofenac sodium. Finally, the toxicity tests recognized that this adsorbent does not affect the germination of L. sativa species. Thus, this adsorbent may become a novel and viable option to be used in the removal of sodium diclofenac.

Green electrospun Janus membrane of polyether block amide (PEBA) doped with hierarchical magnesium hydrogen phosphate for the removal of pharmaceuticals and personal care products

It has been a challenge to prepared polyether block amide (PEBA) fibrous membrane via solution electrospinning. The only few reported methods though involved hazardous solvents and surfactants which were against the principle of green chemistry. In this work, uniform fibrous membrane of PEBA was successfully fabricated by solution electrospinning with a bio-based solvent dihydrolevoglucosenone (Cyrene). To further improve the mechanical strength and adsorption performance of the PEBA membrane, a hierarchical magnesium hydrogen phosphate (MgHPO4·1.2H2O, MHP) was synthesized to blend evenly into the PEBA matrix. A Janus MHP/PEBA membrane with one side of hydrophobic surface and the other side of hydrophilic surface was subsequently prepared, which exhibited fast adsorption, high capacity, good selectivity and reusability towards ibuprofen, acetaminophen, carbamazepine and triclosan. In addition, the Janus membrane showed high removal efficiency of the above contaminants in secondary wastewater effluent with good long term stability. It demonstrated that this Janus MHP/PEBA membrane had a good potential in practical wastewater treatment.

Efficient removal of sertraline hydrochloride from wastewater using banana peels functionalized: performance adsorption, mechanisms and applicability

The presence of sertraline hydrochloride (SER) has been detected in water bodies and wastewater, which encourages the search for alternative treatments for its control and removal. Agro-industrial residues are considered efficient adsorbents and functionalization with magnetic nanoparticles improve the adsorptive properties of these materials, in addition to facilitating their separation from a fluid by an external magnetic field. Thus, this study developed and characterized a new material via the functionalization of the banana peel with iron oxide nanoparticles (BANFunc) for the adsorption of SER in batch experiments. Physicochemical and spectroscopic techniques indicated that the BANFunc functionalization method was effective and improved the adsorption capacity (0.68 and 39.96 mg g-1 for BANPure and BANFunc, respectively). The adsorption studies revealed a maximum adsorptive capacity of 142.85 mg g-1 at 240 min and 318 K. Furthermore, the process presented spontaneous and endothermic behaviour, with a better fit to the pseudo-first-order and Langmuir models for the kinetic and isothermal, respectively. The reuse of the biosorbent was effective for five cycles, and even in the 3rd cycle, the adsorbent showed more than 80% SER removal. The adsorption process can be explained by hydrogen bonds and π-interactions. In the synthetic mixture treatment, the biosorbent demonstrated a satisfactory removal rate, of 86.91%, and individual removals of 83.23%, 89.36% and 88.15% for SER, safranine orange and chloroquine, respectively. Therefore, BANFunc is a promising material for large-scale applications, considering its sustainable character and high treatment efficiency.

Green magnetic carbon/alginate biocomposite beads from iron scrap waste for efficient removal of textile dye and heavy metal

The circular economy can help enhance the value of industrial waste and remediate the environment. This study considers the application of iron scrap from steel production as a free resource to produce magnetic adsorbent beads to remove methylene blue dye and lead (II) ions from wastewater. Composite beads were prepared by incorporating iron scrap and activated carbon into a calcium alginate gel using a simple 'mix and drop' synthesis. The optimized magnetic beads were stable and offered a large specific surface area. The maximum adsorption capacity of the adsorbent, calculated from the Langmuir isotherm model, was 476.19 mg g-1 for methylene blue and 163.93 mg g-1 for lead (II) ions. This study places emphasis upon the zero-waste principle and employs a scalable synthetic approach for the conversion of waste iron scrap into an adsorbent material capable of delivering significant environmental benefits.

Immobilization of hydrochar in cellulose beads for eradicating paracetamol from synthetic and sewage water

Sodium carboxymethyl cellulose polymer was used as a support matrix in immobilizing activated hydrochar derived from bamboo using hydrothermal carbonization. The structural and textural morphology of the beads were studied using FTIR, XRD, SEM/EDS, BET and TGA. Activated hydrochar showed a rough surface with irregular spherical shaped structure. Various oxygenated functional groups in composite beads and activated hydrochar were identified that assist in interaction with PARA pollutant. TGA analysis showed weight loss at three stages 200 °C, 365 °C and 710 °C that leads to complete disintegration of composite beads. BET analysis showed a variation in the surface area between activated hydrochar and beads which could be due to air drying process. Batch adsorption test was conducted for investigating the efficiency of beads in removing PARA from water. Pseudo-second order and Langmuir isotherm fitted the best highlighting chemical mode of adsorption with homogenous interaction on the adsorbent surface. 48.12 mg g-1 was the maximum adsorption capacity estimated from sorption between beads and PARA. For practical applications beads were effectively used in reducing COD levels of PARA spiked sewage water with the defined experimental parameters. Ethanol would be effectively used as regenerating solvent in recycling the beads for the betterment of cost reduction. The activated hydrochar immobilized cellulose beads would be successfully applied as adsorbent in removing target pollutants from water thereby reducing the hurdles faced with respect to fine particles in water treatment.

Removal of Diclofenac and Heavy Metal Ions from Aqueous Media Using Composite Sorbents in Dynamic Conditions

Pharmaceuticals and heavy metals pose significant risks to human health and aquatic ecosystems, necessitating their removal from water and wastewater. A promising alternative for this purpose involves their removal by adsorption on composite sorbents prepared using a conventional layer-by-layer (LbL) method or an innovative coacervate direct deposition approach. In this study, four novel composite materials based on a silica core (IS) and a polyelectrolyte coacervate shell were used for the investigation of dynamic adsorption of three heavy metals (lead, nickel and cadmium) and an organic drug model (diclofenac sodium salt, DCF-Na). The four types of composite sorbents were tested for the first time in dynamic conditions (columns with continuous flow), and the column conditions were similar to those used in wastewater treatment plants. The influence of the polyanion nature (poly(acrylic acid) (PAA) vs. poly(sodium methacrylate) (PMAA)), maintaining a constant poly(ethyleneimine) (PEI), and the cross-linking degree (r = 0.1 and r = 1.0) of PEI chains on the immobilization of these pollutants (inorganic vs. organic) on the same type of composite was also studied. The experiments involved both single- and multi-component aqueous solutions. The kinetics of the dynamic adsorption process were examined using two non-linear models: the Thomas and Yoon-Nelson models. The tested sorbents demonstrated good adsorption capacities with affinities for the metal ions in the following order: Pb2+ > Cd2+ > Ni2+. An increase in the initial diclofenac sodium concentration led to an enhanced adsorption capacity of the IS/(PEI-PAA)c-r1 sorbent. The calculated sorption capacities were in good agreement with the adsorption capacity predicted by the Thomas and Yoon-Nelson models. The substantial affinity observed between DCF-Na and a column containing composite microparticles saturated with heavy metal ions was explained.

Construction of ACNF/Polypyrrole/MIL-100-Fe composites with exceptional removal performance for ceftriaxone and indomethacin inspired by "Ecological Infiltration System"

Developing advanced adsorbents for removing the alarming level of pharmaceuticals active compounds (PhACs) pollution is an urgent task for environmental treatment. Herein, a novel acid-treated carbon nanofiber/polypyrrole/MIL-100-Fe (ACNF/PPy/MIL-100-Fe) with stable 3D-supporting skeleton and hierarchical porous structure had been fabricated to erasure ceftriaxone (CEF) and indomethacin (IDM) from aqueous solution. ACNF as scaffold achieved the highly uniform growth of MIL-100-Fe and PPy. Viewing the large BET surface area (SBET, 999.7 m2/g), highly exposed accessible active sites and copious functional groups, ACNF/PPy/MIL-100-Fe separately showed an excellent adsorption capacity for CEF (294.7 mg/g) and IDM (751.8 mg/g), outstripping the most previously reported adsorbents. Moreover, ACNF/PPy/MIL-100-Fe reached rapid adsorption kinetics and standout reusability property. Further, the redesigned easy-to-recyclable ACF/PPy/MIL-100-Fe inspired by the electrode formation craft achieved prominent adsorption capacity and good reusability property. The adsorption mechanism was evaluated via Fourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The outcomes revealed that the splendid adsorption capability mainly depended on the electrostatic interactions, hydrogen bonding and π-π interactions. This work sheds light on one facile practical strategy to exploit advanced materials in water environmental remediation.

Sodium-alginate-laden MXene and MOF systems and their composite hydrogel beads for batch and fixed-bed adsorption of naproxen with electrochemical regeneration

Sodium alginate (SA)-laden two-dimensional (2D) Ti3C2Tx MXene (MX) and MIL-101(Fe) (a type of metal-organic framework (MOF)) composites were prepared and used for the removal of naproxen (NPX), following the adsorption and electrochemical regeneration processes. The fixed-bed adsorption column studies were also conducted to study the process of removal of NPX by hydrogels. The number of interactions via which the MX-embedded SA (MX@SA) could adsorb NPX was higher than the number of pathways associated with NPX adsorption on the MIL-101(Fe)-embedded SA (MIL-101(Fe)@SA), and the MX and MIL-101(Fe) composite embedded SA (MX/MIL-101(Fe)@SA). The optimum parameters for the electrochemical regeneration process were determined: charge passed and current density values were 169.3 C g-1 and 10 mA cm-2, respectively, for MX@SA, and the charge passed and current density values were 16.7 C g-1 and 5 mA cm-2, respectively, for both MIL-101(Fe)@SA and MX/MIL-101(Fe)@SA. These parameters enabled excellent regeneration, consistent over multiple adsorption and electrochemical regeneration cycles. The mechanism for the regeneration of the materials was proposed that the regeneration of MX@SA and MIL-101(Fe)@SA involved the indirect electrooxidation process in the presence of OH radicals, and the regeneration of MX/MIL-101(Fe)@SA involved the indirect oxidation process in the presence of active chlorine species.

Separable alginate gel spheres encapsulated with La-Fe modified biochar for efficient adsorption of Sb(III) with high capacity

Sb and its compounds have been widely used in various industrial applications. Therefore, the preparation of Sb adsorbents with easy recovery and excellent adsorption levels is an urgent problem that must be resolved. By calcining and treating La/Fe metal-organic frameworks (MOF) biochar as a precursor, a loaded La-Fe-modified water hyacinth biochar was synthesised and used as a filler to synthesise iron alginate composite gel spheres, MBC/algFe. Through a series of static adsorption experiments, the effects of different filler addition ratios, solution pH, reaction time, coexisting ions, and other factors on the adsorption of Sb(III) were investigated. According to the Langmuir model, the maximum adsorption capacity of MBC/algFe at 25 ℃ was 277.8 mg·g-1. The adsorption mechanism mainly involved hydrogen bonding and metal-organic complexation interactions.

Reswellable alginate/activated carbon/carboxymethyl cellulose hydrogel beads for ibuprofen adsorption from aqueous solutions

In this study, alginate (Alg) composite beads were prepared by blending with activated carbon (AC) to enhance adsorption capacity for ibuprofen and carboxymethyl cellulose (CMC) to create a reswellable hydrogel. The dried Alg/AC/CMC composite beads could be recovered to sizes and morphologies similar to the initial hydrogel states via a simple reswelling process; however, the dried Alg/AC composite beads without CMC could not be recovered to the initial hydrogel state. Following the reswelling process, the dried Alg/AC/CMC beads demonstrated an 86 % recovery (qe = 34.0 mg/g) in the adsorption capacity for ibuprofen compared to the initial hydrogel beads (qe = 39.6). In contrast, the reswelled Alg/AC beads exhibited only 18 % (qe = 8.6) of the initial adsorption capacity (qe = 48.1). We elucidated the effects of the substitution degree of CMC, AC content, and solution pH on the reswelling property and ibuprofen adsorption capacity of the Alg/AC/CMC composite beads. The adsorption kinetics and isotherms of the prepared composite beads in the hydrogel and reswelled states fit the pseudo-second-order and Langmuir models, respectively. Furthermore, the reswelled Alg composite beads exhibited high adsorption capacity (>93 %) after 10 cycles. Taken together, our findings indicate that the Alg/AC/CMC composite beads can be used as adsorbents without a considerable decrease in adsorption performance by reswelling the beads with distilled water after long-term storage in a dry state.

Insights into Recent Advances of Biomaterials Based on Microbial Biomass and Natural Polymers for Sustainable Removal of Pharmaceuticals Residues

Pharmaceuticals are acknowledged as emerging contaminants in water resources. The concentration of pharmaceutical compounds in the environment has increased due to the rapid development of the pharmaceutical industry, the increasing use of human and veterinary drugs, and the ineffectiveness of conventional technologies to remove pharmaceutical compounds from water. The application of biomaterials derived from renewable resources in emerging pollutant removal techniques constitutes a new research direction in the field. In this context, the article reviews the literature on pharmaceutical removal from water sources using microbial biomass and natural polymers in biosorption or biodegradation processes. Microorganisms, in their active or inactive form, natural polymers and biocomposites based on inorganic materials, as well as microbial biomass immobilized or encapsulated in polymer matrix, were analyzed in this work. The review examines the benefits, limitations, and drawbacks of employing these biomaterials, as well as the prospects for future research and industrial implementation. From these points of view, current trends in the field are clearly reviewed. Finally, this study demonstrated how biocomposites made of natural polymers and microbial biomass suggest a viable adsorbent biomaterial for reducing environmental pollution that is also efficient, inexpensive, and sustainable.

Encapsulation of activated carbon into calcium alginate microspheres toward granular-activated carbon adsorbents for elemental mercury capture from natural gas

Activated carbon (AC) is an effective adsorbent for removing environmental pollutants. However, the traditional powder form of AC shows difficulty in handling during application which widely limits its utilization on the industrial scale. Herein, to avoid such limitation, traditional AC powder was encapsulated into calcium alginate (CA) microspheres. Calcium alginate/activated carbon (CAA) composite microspheres were prepared via cross-linking of sodium alginate/activated carbon composite solutions in a calcium chloride solution. Furthermore, in order to boost adsorption affinity of CAA composite microspheres toward elemental mercury (Hg°), ammonium iodide (NH₄I)-treated calcium alginate/activated carbon (NCA) composite microspheres were obtained by a simple impregnation method using NH₄I treatment. The morphological, structural, and textural properties of the microspheres were characterized and their Hg° adsorptive capacity was tested at different temperatures. Interestingly, the maximum adsorption capacity of NCA adsorbent composite microspheres was determined as 36,056.5 μg/g at a flow rate of 250 mL/min, temperature of 25 °C, and 500 μg/Nm³ of Hg° initial concentration. The Gibbs free energy (ΔG°) for NCA adsorbent composite microspheres varied from - 8.59 to - 10.54 kJ/mol indicating a spontaneous adsorption process with an exothermic nature. The experimental Hg° breakthrough curve correlated well with Yoon‒Nelson and Thomas models. The breakthrough time (t_b) and equilibrium time (t_e) were found to be 7.5 days and 23 days, respectively. Collectively, the findings of this work indicate a good feasibility of using NCA composite microspheres as potential adsorbents for removing Hg° from natural gas.

Efficient Removal of Analgesic and Anti-Inflammatory Drugs from Sewage Treatment Plant Effluents Using Magnetite Nanoparticles Synthesized Red Mud

Due to the COVID-19 epidemic, the consumption of pharmaceuticals, especially paracetamol, has sharply increased on a global scale. The increasing concentration of analgesic and anti-inflammatory drugs (AAIDs) in the aquatic medium is a global problem for human and aquatic life. Therefore, simple and effective treatment options for removing AAIDs from wastewater after the COVID-19 pandemic are needed. The removal of AAIDs (acetaminophen, acetylsalicylic acid, codeine, diclofenac, ibuprofen, indomethacin, ketoprofen, mefenamic acid, naproxen, and phenylbutazone) from sewage treatment plant (STP) effluents by the prepared magnetite nanoparticles synthesized from red mud (mNPs-RM) is presented for the first time in this study. The removal efficiencies of AAIDs onto mNPs-RM were determined to be between 90% (diclofenac) and 100% (naproxen, codeine, and indomethacin). Acetaminophen (paracetamol) was used as a model compound in kinetic and isotherm model studies. The adsorption of acetaminophen was matched well with the pseudo second order kinetic model. Film diffusion governed its rate mechanism. The Freundlich isotherm model preferably fitted the adsorption data with an adsorption capacity of 370 mg/g at 120 min contact time at pH 7.0 at 25 °C. Furthermore, the regenerated mNPs-RM were used four times without affecting the adsorption capacity and the magnetic separability. mNPs-RM can be used as a simple, inexpensive and effective adsorbent for removing AAIDs from STP effluents. Also, low cost adsorbent obtained from industrial waste could be employed to replace the high cost activated carbons for the adsorption of other micro pollutants in STP effluents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11270-023-06404-7.

Effective removal of selected pharmaceuticals from sewerage treatment plant effluent using natural clay (Na-montmorillonite)

The consumption of pharmaceuticals has rapidly increased on a global scale due to the serious increase in Covid-19, influenza and respiratuar sinsityal virus, which is called "triple epidemic" in the world. The use of non-prescription analgesic and anti-inflammatory drugs (AAIDs), especially paracetamol, is higher compared to pre-pandemic. This increased the AAIDs load discharged to the aqueous media through sewerage treatment plant (STP). Therefore, simple and effective treatment options for removing AAIDs from STP effluents are needed. The aim of the study was to remove AAIDs (paracetamol, acetylsalicylic acid, codeine, diclofenac, ibuprofen, indomethacin, ketoprofen, mefenamic acid, naproxen, and phenylbutazone) from STP effluents by nearly pure natural clay Na-montmorillonite. The Na-montmorillonite taken from the Ordu region in the northern part of Turkey. Surface area of the Na-montmorillonite is 99.58 m2/g and CEC is 92.40 meq/100 g. The removal efficiencies of AAIDs using Na-montmorillonite were between 82 ± 5% (ibuprofen) and 94 ± 4% (naproxen). Paracetamol was used as a model compound in kinetic and isotherm model studies. Freundlich isotherm model and the pseudo second order kinetic model were the best-fit using the obtained experimental data. Film diffusion governed its rate mechanism. The paracetamol adsorption capacity was acquired as 244 mg/g at 120 min contact time at pH 6.5 at 25 °C. With this study, it could be shown that montmorillonite can be used effectively to eliminate paracetamol from STP effluent. Natural clay can be used as a simple, inexpensive and effective adsorbent for removing AAIDs from STP effluents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13201-023-01930-5.

Natural Polymer-Based Graphene Oxide Bio-nanocomposite Hydrogel Beads: Superstructures with Advanced Potentials for Drug Delivery

The current study sought to create graphene oxide-based superstructures for gastrointestinal drug delivery. Graphene oxide has a large surface area that can be used to load anti-cancer drugs via non-covalent methods such as surface adsorption and hydrogen bonding. To enhance the bio-applicability of graphene oxide, nano-hybrids were synthesized by encapsulating the graphene oxide into calcium alginate hydrogel beads through the dripping-extrusion technique. These newly developed bio-nanocomposite hybrid hydrogel beads were evaluated in structural analysis, swelling study, drug release parameters, haemolytic assay, and antibacterial activity. Doxorubicin served as a model drug. The drug entrapment efficiency was determined by UV-spectroscopy analysis and was found to be high at ⁓89% in graphene oxide hybrid hydrogel beads. These fabricated hydrogel beads ensure the drug release from a hybrid polymeric matrix in a more controlled and sustained pattern avoiding the problems associated with a non-hybrid polymeric system. The drug release study of 12 h shows about 83% release at pH 6.8. In vitro drug release kinetics proved that drug release was a Fickian mechanism. The cytotoxic effect of graphene oxide hybrid alginate beads was also determined by evaluating the morphology of bacterial cells and red blood cells after incubation. Additionally, it was determined that the sequential encapsulation of graphene oxide in alginate hydrogel beads hides its uneven edges and lessens the graphene oxide's negative impacts. Also, the antibacterial study and biocompatibility of fabricated hydrogel beads made them potential candidates for gastrointestinal delivery.