Adsorption Of Pharmaceuticals Research Articles

Miscanthus x giganteus biochar: Effective adsorption of pharmaceuticals from model solution and hospital wastewater

This study investigated the adsorption of pharmaceuticals, including atenolol (AT), 17-α-ethinylestradiol (EE2), and sulfamethoxazole (SMX), in model solutions and in the effluent from a hospital wastewater treatment plant. The pharmaceuticals were adsorbed on biochar prepared from Miscanthus x giganteus biomass obtained from the phytoremediation of contaminated or marginal soil. The feedstock was pyrolyzed at 360 °C (M-3) and 500 °C (M-5). The representation of functional groups, specific surface area, porosity, and pore volume were lower for M-5. Pore diameters were comparable, but their depth decreased for M-5. The specific surface area and porosity surface area of M-5 were 30 times higher after 4 h of shaking compared to properties without shaking. The biochar leachate pH was 9.8 ± 1.0 (M-3), and 11.1 ± 1.1 (M-5). No desorption of potentially risk organic compounds was detected. M-3 was generally a better adsorption material. The removal of EE2, AT and SMX was greater than 90%, 70% and 30 % respectively after 4 h in model waters. There was no evidence of a linear relationship between the sorption efficiency of pharmaceuticals and the biochar dose. Sorption experiments with real wastewater from a hospital wastewater treatment plant demonstrated high removal rates of monitored pharmaceuticals, including e.g. SMX (80%), trimethoprim (91%), venlafaxine (100%), clarithromycin (96%), tramadol (93%), diclofenac (86%). It was proven that the efficiency of the adsorption process is influenced not only by the dose or physico-chemical properties of the biochar, but also by the initial concentration of the pharmaceutical and its properties. The presence of other components of real wastewater, which can cause competitive sorption and overlapping of active centers on the surface of the biochar, also decreased the efficiency. The results demonstrate that both biochars are suitable for tertiary or quaternary water treatment for pharmaceutical removal. Due to the lower energetic, and therefore economic, costs of pyrolysis, a lower pyrolysis temperature can be preferred.

How the chitosan structure can affect the adsorption of pharmaceuticals from wastewaters: An overview

The disposal of pharmaceutical compounds in wastewater is a significant environmental and health challenge. These drug residues can have adverse effects on aquatic ecosystems and human health. Chitosan, a natural polysaccharide derived from chitin, is promising as an effective material for adsorbing pharmaceutical waste due to its unique chemical structure containing amino and hydroxy functional groups that facilitate interactions with organic molecules in wastewater. Chitosan can adopt various structural forms, such as hydrogels, nanoparticles, beads, membranes, fibers, and aerogels, which offer opportunities to optimize its performance in adsorbing drug waste. In this review, which includes articles published in the last 5 years, the influence of chitosan's structural forms, particularly on the adsorption of pharmaceutical compounds in wastewater is explored. Furthermore, the different synthesis and fabrication methods for each chitosan form and highlight their characteristics, advantages, and specific applications, are discussed. Additionally, this review delves into the adsorption mechanisms involved in each form.

Hydroxyalkyl Amination of Agarose Gels Improves Adsorption of Bisphenol A and Diclofenac from Water: Conceivable Prospects

The hydroxyalkyl amination of agarose gels was studied as an approach to improve adsorption of polyphenols and pharmaceuticals from water. Three commercially available agarose gels, Zetarose FlashFlow4, ZetaCell-CL6B and Sepharose 4B were chemically modified using tris-(hydroxymethyl)aminomethane, TRIS, and ethanolamine, EA. The adsorbed amounts of bisphenol A and diclofenac were significantly higher on TRIS- and EA-derivatives compared with the parent gels. Regarding bisphenol A adsorption on TRIS-ZetaCell-CL6B, a maximal adsorption capacity, Q max of 16 μmol/mL gel and an equilibrium dissociation constant KL of 2.7 × 10−4 mol/L were observed. Filtration of diclofenac-contaminated water through TRIS-Zetarose FlashFlow 4 resulted in a 10-fold reduction of the pollutant concentration within 64 column volumes of the effluent. The moderate binding affinity of polyphenols to TRIS- and EA-adsorbents facilitates efficient polyphenol desorption and column regeneration. The effects of TRIS- and EA-substituents in agarose gels, can be harnessed for the development of environmental adsorbents, as well as for the preparative separation of polyphenols and pharmaceuticals. We consider the physical shapes and textures of the prospective adsorbents with a particular focus on spongy macroporous cryogels. These innovative materials hold promise for future applications in liquid and air filtration.

Preparation of Chladophora‐Based Biochar and Its Adsorption Properties for Antibiotics

AbstractThe biochar prepared by Chladophora (CB) was used to adsorb the ibuprofen and ofloxacin in sewage. SEM showed that CB preserved the natural tubular structure and increased its specific surface area. According to the BET results, the specific surface area of CB was 296.831 m2 g‐1. The adsorption of ibuprofen and ofloxacin on biochar conformed to the pseudo second‐order kinetic model, indicating that their adsorption rate was controlled by the chemical adsorption mechanism. According to the adsorption isotherms study, the adsorption of ibuprofen on CB met the Dubin‐Radushkevich model, while it fitted well with the Freundlich model for ofloxacin adsorption, making their adsorption onto biochar relating to non‐uniform surface and adsorption layer, respectively. The pore filling and electrostatic interaction were considered the main mechanism for the adsorption of pharmaceuticals and personal care products on CB, whereas the π‐π electron donor acceptor (EDA) interaction and hydrogen bond would also partially contribute to the adsorption process.

Adsorption of contaminants by nanomaterials synthesized by green and conventional routes: a critical review.

Nanomaterials, due to their large surface area and selectivity, have stood out as an alternative for the adsorption of contaminants from water and effluents. Synthesized from green or traditional protocols, the main advantages and disadvantages of green nanomaterials are the elimination of the use of toxic chemicals and difficulty of reproducing the preparation of nanomaterials, respectively, while traditional nanomaterials have the main advantage of being able to prepare nanomaterials with well-defined morphological properties and the disadvantage of using potentially toxic chemicals. Thus, based on the particularities of green and conventional nanomaterials, this review aims to fill a gap in the literature on the comparison of the synthesis, morphology, and application of these nanomaterials in the adsorption of contaminants in water. Focusing on the adsorption of heavy metals, pesticides, pharmaceuticals, dyes, polyaromatic hydrocarbons, and phenol derivatives in water, for the first time, a review article explored and compared how chemical and morphological changes in nanoadsorbents synthesized by green and conventional protocols affect performance in the adsorption of contaminants in water. Despite advances in the area, there is still a lack of review articles on the topic.

Comparative removal of pharmaceuticals in aqueous phase by agricultural waste-based biochars.

The intensification of pharmaceutical use globally has led to an increase in the number of water bodies contaminated by drugs, and an effective strategy must be developed to address this issue. In this work, several biochars produced from Miscanthus straw pellets (MSP550, MSP700) and wheat straw pellets (WSP550, WSP700) at 550 and 700°C, respectively, were selected as adsorbents for removing various pharmaceuticals, such as pemetrexed (PEME), sulfaclozine (SCL), and terbutaline (TBL), from the aqueous phase. The biochar characterizations (physicochemical properties, textural properties, morphological structures, and zeta potentials) and adsorptive conditions (contact times, temperatures, and pH effect) were investigated. The infrared and Raman spectra of biochars before and after pharmaceutical adsorption, as well as quantum chemical computations, were carried out to explore the adsorption mechanisms. The results showed that the general adsorption abilities of biochars for pharmaceuticals were in the order of WSP700 > MSP700 > MSP550 > WSP550. Both the higher drug concentration and higher temperature improved biochar adsorption. By decreasing the pH, the adsorption amounts increased for PEME and SCL. However, TBL exhibited the best adsorption at pH7, whereas a weakening of affinity occurred at lower or higher pH values. Electrostatic interactions and hydrogen bonding were the main adsorptive mechanisms between all biochars and pharmaceuticals. π-π interactions played a role in the adsorption process of low-temperature-prepared biochars (MSP550 and WSP550). This work can provide new insights into the control of pharmaceuticals from water with low-cost adsorbents. PRACTITIONER POINTS: Use of biochars for pharmaceuticals removal from aqueous phase. Characterization of biochars : physical and chemical properties, textural and surface properties. Simulation calculation for characterization of pharmaceuticals. Kinetic studies of pharmaceuticals adsorption on biochars. DRIFTS and Raman analysis for the understanding of adsorption process.

Aging microplastics enhances the adsorption of pharmaceuticals in freshwater

Plastic pollution is an increasing environmental concern. Pollutants such as microplastics (< 5 mm) and pharmaceuticals often co-exist in the aquatic environment. The current study aimed to elucidate the interaction of pharmaceuticals with microplastics and ascertain how the process of photo-oxidation of microplastics affected the adsorption of the pharmaceuticals. To this end, a mixture containing ibuprofen, carbamazepine, fluoxetine, venlafaxine and ofloxacin (16 μmol L−1 each) was placed in contact with one of six either virgin or aged microplastic types. The virgin microplastics were acquired commercially and artificially aged in the laboratory. Polypropylene, polyethylene, polyethylene terephthalate, polyamide, polystyrene, and polyvinyl chloride microparticles at two sizes described as small (D50 < 35 μm) and large (D50 95–157 μm) were evaluated. Results demonstrated that the study of virgin particles may underestimate the adsorption of micropollutants onto microplastics. For virgin particles, only small microparticles of polypropylene, polyethylene, polyvinyl chloride, and both sizes of polyamide adsorbed pharmaceuticals. Aging the microplastics increased significantly the adsorption of pharmaceuticals by microplastics. Fluoxetine adsorbed onto all aged microplastics, from 18 % (large polyethylene terephthalate) to 99 % (small polypropylene). The current investigation highlights the potential of microplastics to act as a vector for pharmaceuticals in freshwater, especially after aging.

Pharmaceutical adsorption on NaOH-treated rice husk-based activated carbons: Kinetics, thermodynamics, and mechanisms

This study aims to explore the adsorption behavior of four pharmaceuticals: ciprofloxacin (CIP), sulfamethoxazole (SUL), diclofenac (DIC), and acetaminophen (ACE) on activated carbons produced from rice husk using different NaOH-based protocols at 800 °C. The main objective is to assess and compare the efficiency of activated carbons synthesized by solid-solid and wet treatment methods on pharmaceutical adsorption. All three activated carbons displayed strong affinity towards pharmaceutical adsorption, but the material produced with wet protocol after the carbonization process demonstrated the highest adsorption capacity and the lowest equilibrium time (15 min) due to its superior textural properties and higher surface area (1671 ± 31 m2 g−1). Further investigation of pharmaceutical adsorption in synthetic urine was carried out using the mentioned material. The results revealed that in both mono and multicomponent systems, CIP, SUL, and DIC did not exhibit any significant competition with each other or with the urine matrix. However, ACE showed competition for adsorption sites. For both CIP and ACE, the diffusion boundary layer and the adsorption process were identified as the velocity-limiting steps for adsorption in urine. To better understand the adsorption mechanism, both experimental and computational tools were employed. The results revealed that ACE exhibited typical Langmuir-like adsorption behavior with an exothermic nature on the mentioned material with an adsorption capacity of 209.6 ± 5.6 mg g−1. Regarding CIP, its adsorption displayed a non-typical endothermic nature, which was attributed to steric hindrance due to its zwitterionic structure and the porosity in the adsorbent. Analyzing the combination of Redlich-Peterson and Langmuir models with computational analysis supported this finding. However, the material exhibited an impressive adsorption capability of 584.4 ± 21.5 mg g−1. The parameter φ (cncreased cost associated with enhancing the adsorption process) revealed an augmentation in adsorption capacities of 45.1 and 125.6 mg USD−1 for ACE and CIP, respectively, compared to the raw rice husk. This research underscores the prospect of employing agricultural and industrial byproducts to create activated carbons capable of efficiently extracting pharmaceuticals from intricate mixtures, such as urine.

High content of low molecular weight organics does not always affect pharmaceutical adsorption on activated carbon: The case of acetate, propionate and ethanol in source-separated urine

Adsorption on activated carbon is a common process to remove pharmaceuticals in wastewater treatment. Activated carbon adsorption is usually applied to wastewater with a low content of biological degradable organics, i.e. after biological treatment. Especially low molecular weight (LMW) compounds are known to compete with pharmaceuticals for adsorption sites. The goal of this study was to test the hypothesis that biological treatment is necessary for efficient pharmaceutical removal. Source-separated urine after anaerobic storage (anaerobically stored urine) and after aerobic biological removal of organics without nitrification (organics-depleted urine) were used in this study. In anaerobically stored urine 60% of the organic compounds were LMW organics, of which about 40% were acetate and propionate. 74% of the DOC and 100% of acetate and propionate were removed during aerobic biological treatment. To investigate the effect of the organic compounds on pharmaceutical removal, sorption experiments with 19 spiked pharmaceuticals and one artificial sweetener were conducted with powdered activated carbon. Ethanol, another LMW organic, was included in the study, as it is regularly used for pharmaceutical spiking thereby strongly increasing the DOC content. The experiments showed that the adsorption of the pharmaceuticals and the sweetener were hardly affected by the easily biodegradable LMW organics or ethanol. Therefore, it was concluded that biological pre-treatment is not necessary for efficient pharmaceutical adsorption. Since acetate, propionate and ethanol contribute substantially to the DOC content but do not absorb UV light, the latter is recommended as indicator for pharmaceutical removal in solutions with high contents of biodegradable LMW organics.

The Influences of Pore Blockage by Natural Organic Matter and Pore Dimension Tuning on Pharmaceutical Adsorption onto GO-Fe3O4.

The ubiquitous presence of pharmaceutical pollution in the environment and its adverse impacts on public health and aquatic ecosystems have recently attracted increasing attention. Graphene oxide coated with magnetite (GO-Fe3O4) is effective at removing pharmaceuticals in water by adsorption. However, the myriad compositions in real water are known to adversely impact the adsorption performance. One objective of this study was to investigate the influence of pore blockage by natural organic matter (NOM) with different sizes on pharmaceutical adsorption onto GO-Fe3O4. Meanwhile, the feasibility of pore dimension tuning of GO-Fe3O4 for selective adsorption of pharmaceuticals with different structural characteristics was explored. It was shown in the batch experiments that the adsorbed pharmaceutical concentrations onto GO-Fe3O4 were significantly affected (dropped by 2-86%) by NOM that had size ranges similar to the pore dimensions of GO-Fe3O4, as the impact was enhanced when the adsorption occurred at acidic pHs (e.g., pH 3). Specific surface areas, zeta potentials, pore volumes, and pore-size distributions of GO-Fe3O4 were influenced by the Fe content forming different-sized Fe3O4 between GO layers. Low Fe contents in GO-Fe3O4 increased the formation of nano-sized pores (2.0-12.5 nm) that were efficient in the adsorption of pharmaceuticals with low molecular weights (e.g., 129 kDa) or planar structures via size discrimination or inter-planar π-π interaction, respectively. As excess larger-sized pores (e.g., >50 nm) were formed on the surface of GO-Fe3O4 due to higher Fe contents, pharmaceuticals with larger molecular weights (e.g., 296 kDa) or those removed by electrostatic attraction between the adsorbate and adsorbent dominated on the GO-Fe3O4 surface. Given these observations, the surface characteristics of GO-Fe3O4 were alterable to selectively remove different pharmaceuticals in water by adsorption, and the critical factors determining the adsorption performance were discussed. These findings provide useful views on the feasibility of treating pharmaceutical wastewater, recycling valuable pharmaceuticals, or removing those with risks to public health and ecosystems.

Removal, Adsorption, and Cleaning of Pharmaceutical on Polyamide RO and NF Membranes.

Pharmaceuticals are present in various waters and can be almost completely rejected by membrane separation processes, i.e., nanofiltration (NF) and reverse osmosis (RO). Nevertheless, the adsorption of pharmaceuticals can decrease their rejection, so adsorption can be considered a very important removal mechanism. In order to increase the lifetime of the membranes, the adsorbed pharmaceuticals must be cleaned from the membrane. The used pharmaceutical (albendazole), the most common anthelmintic for threatening worms, has been shown to adsorb to the membrane (solute-membrane adsorption). In this paper, which is a novelty, commercially available cleaning reagents, NaOH/EDTA solution, and methanol (20%, 50%, and ≥99.6%) were used for pharmaceutical cleaning (desorption) of the NF/RO membranes used. The effectiveness of the cleaning was verified by Fourier-transform infrared spectra of the membranes. Of all the chemical cleaning reagents used, pure methanol was the only cleaning reagent that removed albendazole from the membranes.

Green Synthesis of Nanoparticles Mediated by Deep Eutectic Solvents and Their Applications in Water Treatment

The use of environmentally friendly deep eutectic solvents (DES) in green synthesis of different types of nanoparticles has garnered increasing interest in recent years. The application of these materials in water treatment, mainly by adsorption or degradation, is emerging as a sustainable alternative to conventional methodologies. However, the information about the green synthesis of nanoparticles (NPs) using DES is dispersed in the literature. This review is focused on compiling and systematizing information regarding DES-mediated NP synthesis, the application of these NPs in water treatment, and future perspectives of these technologies. DES represent an excellent alternative to traditional solvents in NP synthesis due to their low toxicity, low cost, and being environmentally friendly. The possible NP surface functionalization with DES is also attractive as it plays a pivotal role in processes related to water treatment. Modification and synthesis of carbon nanotubes, graphene oxides, magnetic iron oxides, among others, for the adsorption and degradation of organic dyes, pharmaceuticals, metal ions, herbicides, pesticides, and other water contaminants found in recent literature are presented in this work. Finally, the possibility to control NP size and shape can be helpful in the design of new materials for a specific application.

Dissolving Activated Carbon Pellets for Ibuprofen Removal at Point-of-Entry

The increased usage of pharmaceuticals coupled with the desire for greywater reuse to reduce the freshwater demand for potable water requires a user-friendly engineered solution. Activated carbon is a proven technology that is typically used for organic pollutant removal at water treatment plants. Lignite, coconut, and a blend of activated carbon powders were used to develop rapid-dissolving pellets with an inorganic binder. Ibuprofen was the model compound chosen for pharmaceutical adsorption in deionized water and synthetic hydrolyzed and synthetic fresh urine at rapid contact times (0.5 to 30 min) and using various pellet dosages (0.5 to 10 g/L). A cost analysis was performed to determine the feasibility of the engineered solution. With an increase in contact time, the coconut pellets outperformed both the blend and lignite pellets in deionized water at a set pellet dosage. The lignite pellets were the most cost-effective with rapid adsorption in fresh urine and a capacity of 0.089 g ibuprofen/g pellet. Additional optimization parameters include pellet dissolvability, pellet dosage in relation to different pharmaceuticals, and the impact of activated carbon on the household sewage system, and each of these are necessary to determine application feasibility.

Synergetic effect on the adsorption of cationic and anionic emerging contaminants on polymeric membranes containing Modified-Graphene Oxide: Study of mechanism in binary systems

The growing need to explore the adsorption potential of new materials in real water samples triggered the evolution from single to multicomponent systems in the area of adsorption. In this study, PAN membranes containing graphene oxide functionalized with safranin dye (hPAN@GO-SF) were applied in the adsorption of complex dyes, pharmaceuticals and surfactants from water and real samples, in single and binary systems, to evaluate the competitive or cooperative effects of adsorbate mixture on the adsorption mechanism. This is the first time that polymeric membranes containing GO have been used as adsorbent in multicomponent systems. The results obtained in single systems indicated that electrostatic interactions and H-bonding are the main mechanism, but chemisorption is also present. For the multicomponent systems, the adsorption potential of the membrane increased due to cooperative effects, reaching a percentage increase of 141% for DB22, a more than 3X increase for BB7 and exponential increase for SIL and PRO. Suggestion of mechanisms based on adsorbent/adsorbate and adsorbate/adsorbate interactions supported by ion exchange, π-π, H-bonding and electrostatic interactions. Comparing the adsorption capacity of hPAN@GO-SF for contaminants in binary system with other materials in the literature used in single systems, this indicate that membrane is a potential adsorbent for wastewater treatment.

Evaluation of hydroxyapatite-chitosan-magnetite nanocomposites for separation of pharmaceuticals from water: A mechanistic and comparative approach

Binary and ternary composites of hydroxyapatite (HAP), chitosan (CT) and magnetite (MNP) were fabricated to assess the individual role of each constituent and to estimate their optimized proportion for maximizing the adsorption of pharmaceuticals (PCs) from aqueous phase. Batch studies carried out with model ibuprofen (IBU) reveal the significant role of HAP in enhancing the adsorption to binary composites (HAP@CT, HAP@MNP, CT@MNP). Among the HAP@CT composites fabricated with varying proportion, CT proportion of ≧ 50% showed improved adsorptive performance. Highest adsorption of IBU was achieved by the ternary composite of NC6 having a HAP: CT: MNP of 2:5:3. FTIR, VSM, Fe-SEM, TEM studies revealed NC6 to possess magnetic properties, better aqueous phase stability, higher surface area, higher crystallite sized nanoparticles with less agglomeration, and adequate surface functionality as compared to its precursors. The high efficiency and fast kinetics for Ibuprofen (IBU), Deflazacort (DEF), Methylprednisolone (MET) and Norfloxacin (NOR) could be corelated with the structural and physico-chemical nature of the PCs in aqueous phase. Langmuir adsorption capacity of 535.6 mg/g, 833 mg/g, 625 mg/g and 714 mg/g for NOR IBU, MET and DEF respectively was reported with NC6 dosage of 0.01 g/L. NC6 demonstrated faster equilibration time of 30–90 mins with > 85% PCs removal as compared to other reported composites. The results of this study reveal the efficacy of NC6 for fast and high adsorptive removal of diverse types of PCs from both model and hospital wastewater. Also, the reusability and biogenic nature of NC6 is established.

Characterization, evaluation, and mechanism analysis of the functionalization of kaolin with a surfactant for the removal of diclofenac from aqueous solution

Trace pharmaceutical concentrations are commonly found in wastewater worldwide. The high polarity of these pollutant molecules and their low concentrations in the order of micro- nanograms per liter make them difficult to remove by conventional separation units installed in wastewater treatment plants and advanced purification processes. The accumulation of these pollutants in ecosystems has become a critical issue because they pose major threats to flora, fauna, and human health. Diclofenac (DCF) is a pharmaceutical product that belongs to this category, and its adsorption onto clay minerals, notably kaolin, provides an economical and effective approach for addressing wastewater pollution. In this study, kaolin modified with cetylpyridinium chloride (K-CPC) was characterized and evaluated for DCF removal. This modified clay sample had a surface area, pore size, and volume of 5.57 m2/g, 191.6 Å and 0.03 cm3/g, respectively. Under the best operating conditions, 93.53% removal and 392.3 µg/g of DCF adsorption capacity were obtained. Redlich-Peterson and pseudo-second-order equations correlated the pharmaceutical adsorption data. The estimated DCF adsorption enthalpy was −27.87 kJ/mol, which corresponds to an exothermic process. Advanced modelling based on statistical physics was used for a steric analysis of the DCF adsorption mechanism, concluding that it was multi-molecular. DCF adsorption on K-CPC involves physical adsorption, in which hydrogen bonding, π – π interactions, and electrostatic forces play important roles in the removal mechanism. Thus, DCF removal from polluted streams in large-scale applications using this new adsorbent is promising.

Trends in removal of pharmaceuticals in contaminated water using waste coffee and tea-based materials with their derivatives.

The introduction of large amounts of pharmaceuticals into the environmental waters is well-documented in literature with their occurrence reported in all different water matrices accessible to humans and animals. At the same time, the increasing consumption of coffee and tea-based beverages results in the generation of solid waste, which is mostly disposed-off in the environment. To minimize environmental pollution, coffee and tea-based materials have been proposed as suitable options to remove pharmaceuticals in environmental waters. Therefore, this article provides a critical review on the preparation and applications of coffee and tea-based materials in removing pharmaceuticals from contaminated water. In this context, most studies in literature focused on the applications of these materials as adsorbents, while only limited work on their role in degradation of pharmaceuticals is discussed. The successful application in adsorption studies is attributed to high surface areas of adsorbents and the ability to easily modify the adsorbent surfaces by incorporating functional groups that provide additional oxygen atoms, which promote easy interactions with pharmaceuticals. Hence, the adsorption mechanisms are mostly described by hydrogen bonding, electrostatic and π-π interactions with sample pH playing a dominant role in the adsorption process. Overall, the present article focused on the developments, trends and future research direction on the preparations and applications of coffee and tea-based materials for efficient removal of pharmaceuticals in water. PRACTITIONER POINTS: Review of tea and coffee wastes application for removal of pharmaceuticals in water Key applications in adsorption and degradation of pharmaceuticals in water Removal mostly explained by hydrogen bonding, electrostatic, and π-π interactions Trends, gaps, and future research to be explored are reviewed and highlighted.

Synthesis and characterization of super high surface area silica-based nanoparticles for adsorption and removal of toxic pharmaceuticals from aqueous solution

Tetracycline is a broad-spectrum antibiotic that is commonly applied to cure common illnesses in both people and animals. Tetracycline is still one of the most enduring micro-pollutants in the environment due to its indiscriminate misuse. In this study, a high surface area nanoadsorbent aminopropyltriethoxysilane@silica nanoparticles (3-APTS@SNPs) were synthesized and characterized through XRD, BET, XPS, HR-TEM, and FE-SEM. Then it was tested to see if it could adsorb tetracycline from an aqueous solution. The maximal tetracycline adsorption capability of the nanoadsorbent 3-APTS@SNPs was 875.47 mg/g. Additionally, the batch adsorption experiments revealed that 3-APTS@SNPs' adsorption followed and fit the Langmuir isotherm (R2 = 0.999) and pseudo-second-order kinetics (R2 = 0.999), respectively. At pH 7.0, additional tuning using response surface methods and a genetic algorithm increased the 3-APTS@SNPs' overall removal efficiency. The thermodynamic parameter was determined through a study of the effect of temperature, and the reactions were endothermic and chemisorption processes. The mechanism analysis showed that the majority of the adsorption was chemical adsorption (π-π interaction, electrostatic interaction, ion exchange, and chemical bonds) and physical adsorption. An important factor that ensured the adsorbent's significant potential for useful wastewater treatment was that it had exceptional cycle stability and could be quickly recovered from aqueous media using a simple centrifuge.

Recent advances in new generation nanocomposite materials for adsorption of pharmaceuticals from aqueous environment.

With rapid increase in the human population, a large amount of wastewater is generated every year. The availability of fresh water is decreasing at an alarming rate due to rapid industrialization and agricultural development. Pharmaceutical drugs which are credited for improving standards of life worldwide have emerged as major water contaminants, raising global concern about their potential risk to human health and environment. The presence of pharmaceutical compounds is detected in surface water (sea, river, lakes, etc.), groundwater, effluents from municipal, hospitals, and wastewater treatment plants, and even in drinking water. Efficient removal of pharmaceutical pollutants still remains a challenging task. Many techniques, including photodegradation, photocatalysis, oxidation, reverse osmosis, biodegradation, nanofiltration, adsorption, etc., have been used for the remediation of wastewater. Adsorption of pharmaceutical compounds on nanoadsorbents, as a low-cost and feasible technology, has gained immense popularity for wastewater treatment over the last decade. Adsorption techniques can be integrated with wastewater treatment plants to achieve efficient removal on an industrial level. Herein, we review the literature on the remediation techniques used for the pharmaceutical waste treatment using carbon nanotubes, metal oxides, nanoclay, and new-generation MXenes via adsorption. These materials show excellent adsorptive properties owing to their high surface area, low cost, high porosity, easy functionalization, and high surface reactivity. The adsorption mechanism of the nanoadsorbents and their reusability as a factor of sustainability have also been included in the review. The factors affecting the adsorption, including pH, the concentration of adsorbate, ionic strength, and adsorbate dose, have also been discussed.

Ex-situ magnetic activated carbon for the adsorption of three pharmaceuticals with distinct physicochemical properties from real wastewater.

Pharmaceuticals are able to evade conventional wastewater treatments and therefore, are recurrently found in the environment with proven potential to cause harm to human and wildlife. Adsorption onto activated carbon (AC) is a promising complement. However, AC production from non-renewable resources and its difficult after-use recuperation are prohibitive. Hence, a waste-based magnetic activated carbon (MAC) was produced from paper mill sludge, via an ex-situ synthesis, for the adsorptive removal of carbamazepine (CBZ), sulfamethoxazole (SMX) and ibuprofen (IBU) from ultrapure water and wastewater. The MAC was obtained through the promotion of electrostatic interactions between magnetic and activated carbon particles in a water suspension at controlled pH between the points of zero charge of both surfaces. The optimized condition (MACX3) presented remarkable properties regarding specific surface area (SBET=795m2 g-1) and saturation magnetization (MS=19emug-1). Kinetic and equilibrium adsorption studies were performed under batch conditions. Adsorption equilibrium was reached in up to 30min for all pharmaceuticals in both matrices, proving the low dependence on the adsorbate and the broad applicability of MACX3 in pharmaceutical adsorption. Regarding equilibrium experiments, high Langmuir maximum adsorption capacities (qm) were achieved in ultrapure water (up to 711 ± 40 µmol g-1). Equilibrium studies in wastewater revealed a decay in qm when compared to ultrapure water: 28% for CBZ (468 ± 20 µmol g-1 (111 ± 5 mg g-1)), 78% for SMX (145±10 µmol g-1 (37 ± 3 mg g-1)) and 62% for IBU (273 ± 8 µmol g-1 (56 ± 2 mg g-1)), attributed to the wastewater pH, which dictates the speciation of the pharmaceuticals and controls electrostatic interactions between pharmaceuticals and MAC, and to competition effects by organic matter. It was demonstrated the promising applicability of a waste-based ex-situ MAC, rapidly retrievable from water, as an alternative tertiary wastewater treatment for pharmaceuticals removal.