Synthesis of a molecularly imprinted polymer and its application in selective extraction of fenoprofen from wastewater

Insights into the efficiencies of different biological treatment systems for pharmaceuticals removal: A review

This review presents a comprehensive analysis of current research on biological treatment processes for removing pharmaceutical compounds (PhCs) from wastewater. Unlike previous studies on this topic, our study specifically delves into the effectiveness and drawbacks of various treatment approaches such as traditional wastewater treatment facilities (WWTP), membrane bioreactors (MBRs), constructed wetlands (CW), and moving bed biofilm reactors (MBBR). Through the examination and synthesis of information gathered from more than 200 research studies, we have created a comprehensive database that delves into the effectiveness of eliminating 19 particular PhCs, including commonly studied compounds such as acetaminophen, ibuprofen, diclofenac, naproxen, ketoprofen, indomethacin, salicylic acid, codeine, and fenoprofen, amoxicillin, azithromycin, ciprofloxacin, ofloxacin, tetracycline, atenolol, propranolol, and metoprolol. This resource provides a depth and scope of information that was previously lacking in this area of study. Notably, among these pharmaceuticals, azithromycin demonstrated the highest removal rates across all examined treatment systems, with the exception of WWTPs, while carbamazepine consistently exhibited the lowest removal efficiencies across various systems. The analysis showcases the diverse results in removal efficiency impacted by factors such as system configuration, operation specifics, and environmental circumstances. The findings emphasize the critical need for continued innovation and research, specifically recommending the integration of advanced oxidation processes (AOPs) with existing biological treatment methods to improve the breakdown of recalcitrant compounds like carbamazepine. PRACTITIONER POINTS: Persistent pharmaceuticals harm aquatic ecosystems and human health. Biological systems show varying pharmaceutical removal efficiencies. Enhancing HRT and SRT improves removal but adds complexity and costs. Tailored treatment approaches needed based on contaminants and conditions.

Development and application of a new QuEChERS-molecularly imprinted solid phase extraction (QuEChERS-MISPE) technique for analysis of DDT and its derivatives in vegetables

The current study synthesized a molecularly imprinted polymer, combined it with the QuEChERS method to form a new hybrid technique, the QuEChERS-MISPE as an alternative to the QuEChERS-dSPE for analysis of DDTs as model pesticides. Batch studies confirmed that the binding of the DDTs to the MIP cavities formed a monolayer formation through chemisorption resulting in an adsorption capacity of 429 ng g-1. A study of matrix effects indicated signal suppression for both techniques. However, the new QuEChERS-MISPE technique is less affected by matrix effects, has better sensitivity and recoveries compared to the conventional QuEChERS-dSPE technique. Application of the new QuEChERS-MISPE technique detected trace levels of DDTs in vegetables in South Africa. However, a health risk assessment indicated that potential risks for consumers was minimal. Although the risk is minimal, the detection of DDTs in vegetables in South Africa should be a concern and more constant monitoring is required.

Recent Developments in the Detection of Organic Contaminants Using Molecularly Imprinted Polymers Combined with Various Analytical Techniques

Molecularly imprinted polymers (MIPs) encompass a diverse array of polymeric matrices that exhibit the unique capacity to selectively identify a designated template molecule through specific chemical moieties. Thanks to their pivotal attributes, including exceptional selectivity, extended shelf stability, and other distinct characteristics, this class of compounds has garnered interest in the development of highly responsive sensor systems. As a result, the incorporation of MIPs in crafting distinctive sensors and analytical procedures tailored for specific analytes across various domains has increasingly become a common practice within contemporary analytical chemistry. Furthermore, the range of polymers amenable to MIP formulation significantly influences the potential utilization of both conventional and innovative analytical methodologies. This versatility expands the array of possibilities in which MIP-based sensing can be employed in recognition systems. The following review summarizes the notable progress achieved within the preceding seven-year period in employing MIP-based sensing techniques for analyte determination.

A sensitive fluorescent assay based on gold-nanoclusters coated on molecularly imprinted covalent organic frameworks and its application in malachite green detection

Malachite green (MG), as a parasiticide, is widely used in aquaculture to increase the production of the fishery industry. It poses a great danger to both the food system and the human body. In this study, a one-pot reverse microemulsion polymerization was employed to combine the gold nanoclusters (AuNCs) with molecularly imprinted polymers (MIPs) and covalent organic frameworks (COFs) to synthesize an efficient fluorescent hybrid probe (AuNCs@COFs@MIPs) for selective detection of MG. The specific recognition of AuNCs@COFs@MIPs towards MG triggers the fluorescence quenching of AuNCs. The fluorescent response was linearly related to the concentration over the range of 10-150 nmol/L with a limit of detection of 2.78 nmol/L. In addition, the proposed probe was further applied to fish and water samples. A favorable recovery ranged from 97.34 to 101.51 % toward trace amounts of MG indicating its promising application for detecting residue of veterinary drugs.

Overview of African water resources contamination by contaminants of emerging concern

This review look at several classes of contaminants of emerging concern (CECs) in conventional and non-conventional water resources across the African continent's five regions. According to the review, pharmaceuticals, endocrine-disrupting chemicals, personal care products, pesticides, per- and polyfluoroalkyl compounds, and microplastics were found in conventional and non-conventional water resources. Most conventional water resources, such as rivers, streams, lakes, wells, and boreholes, are used as drinking water sources. Non-conventional water sources, such as treated wastewater (effluents), are used for domestic and agricultural purposes. However, CECs remain part of the treated wastewater, which is being discharged to surface water or used for agriculture. Thus, wastewater (effluent) is the main contributor to the pollution of other water resources. For African countries, the prevalence of rising emerging pollutants in water poses a severe environmental threat. There are different adverse effects of CECs, including the development of antibiotic-resistant bacteria, ecotoxicological effects, and several endocrine disorders. Therefore, this needs the urgent attention of the African Union, policymakers, Non-Governmental Organizations, and researchers to come together and tackle the problem.

Molecularly imprinted polymers for environmental adsorption applications

Molecular imprinting polymers (MIPs) are synthetic materials with pores or cavities to specifically retain a molecule of interest or analyte. Their synthesis consists of the generation of three-dimensional polymers with specific shapes, arrangements, orientations, and bonds to selectively retain a particular molecule called target. After target removal from the binding sites, it leaves empty cavities to be re-occupied by the analyte or a highly related compound. MIPs have been used in areas that require high selectivity (e.g., chromatographic methods, sensors, and contaminant removal). However, the most widely used application is their use as a highly selective extraction material because of its low cost, easy preparation, reversible adsorption and desorption, and thermal, mechanical, and chemical stability. Emerging pollutants are traces of substances recently found in wastewater, river waters, and drinking water samples that represent a special concern for human and ecological health. The low concentration in which these pollutants is found in the environment, and the complexity of their chemical structures makes the current wastewater treatment not efficient for complete degradation. Moreover, these substances are not yet regulated or controlled for their discharge into the environment. According to the literature, MIPs, as a highly selective adsorbent material, are a promising approach for the quantification and monitoring of emerging pollutants in complex matrices. Therefore, the main objective of this work was to give an overview of the actual state-of-art of applications of MIPs in the recovery and concentration of emerging pollutants.

Development and application of a membrane assisted solvent extraction-molecularly imprinted polymer based passive sampler for monitoring of selected pharmaceuticals in surface water

In this work, we demonstrate the development, evaluation and pre-liminary application of a novel passive sampler for monitoring of selected pharmaceuticals in environmental waters. The samplers were calibrated in laboratory-based experiments to obtain sampling rates (Rs) for carbamazepine, methocarbamol, etilefrine, venlafaxine and nevirapine. Passive sampling was based on the diffusion of the target pharmaceuticals from surface water through a membrane bag which housed an ionic liquid as a green receiving solvent and a molecularly imprinted polymer. Effects of biofouling, deployment time and solvent type for the receiver phase were optimized for selective uptake of analytes in surface water. Notably, there was a decrease in the uptake of selected pharmaceuticals and consequently a decrease in their sampling rates in the presence of biofouling. The optimum matrix-matched sampling rates ranged from 0.0007 - 0.0018 L d^-1 whilst the method detection and quantification limits ranged from 2.45 - 3.26 ng L^-1 and 8.06 - 10.81 ng L^-1, respectively. The optimized passive sampler was deployed in a dam situated in the heart of a typical highly populated township in the Gauteng Province of South Africa. Only etilefrine and methocarbamol were detected and quantified at maximum time weighted average concentrations of 12.88 and 72.29 ng L^-1, respectively.

Method optimisation and application based on solid phase extraction of non steroidal anti-inflammatory drugs, antiretroviral drugs, and a lipid regulator from coastal areas of Durban, South Africa

This study presents an optimized method that is applicable in monitoring the occurrence of pharmaceuticals in a wide range of aquatic environments. The optimised Solid Phase Extraction method is based on Bond Elut Plexa cartridges for the identification and quantification of three non-steroidal anti-inflammatory drugs, three antiretroviral drugs and a lipid regulator in the coastal area of Durban city, South Africa covering four seasons. The extracted compounds are qualitatively and quantitatively detected by a high-performance liquid phase chromatographic instrument coupled to a photodiode array detector. The recoveries range from 62 to 110% with a Relative Standard Deviation of 0.56−4.68%, respectively, for the determination of emtricitabine, tenofovir, naproxen, diclofenac, ibuprofen, efavirenz, and gemfibrozil. The analytical method is validated by spiking estuarine water samples with 5 µg L− 1 of a mixture containing the target pharmaceuticals and the matrix detection limit is established to be 0.62–1.78 µg L− 1 for the target compounds. The optimized method is applied to seasonal monitoring of pharmaceuticals at chosen study sites from winter and spring of 2019 and summer and autumn of 2020. The results indicate the concentration of the pharmaceuticals studied varies with the type of aquatic environment and season.

Application of Molecularly Imprinted Polymers in the Analysis of Waters and Wastewaters

The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications.

Occurrence and ecotoxicological risk assessment of non-steroidal anti-inflammatory drugs in South African aquatic environment: What is known and the missing information?

Non-steroidal anti-inflammatory drugs (NSAIDs) are medications used individually or as mixtures with other pharmaceuticals for the treatment of various illnesses. Their easy accessibility and high human consumption have resulted to their detection at high concentrations in South African water resources. In the present work, an extensive review of the occurrence and ecotoxicological risk assessment of NSAIDs in South African aquatic environment is provided. Reviewed literature suggested ibuprofen, naproxen, diclofenac, ketoprofen and fenoprofen as the most prominent NSAIDs in the South African aquatic environment. Among these NSAIDs, higher concentrations of ibuprofen are common in South African waters. As a result, this drug was found to pose high ecotoxicological risks towards the aquatic organisms with the highest risk quotients of 14.9 and 11.9 found for algae in surface water and wastewater, respectively. Like in other parts of the world, NSAIDs are not completely removed in wastewater treatment plants. Removal efficiencies below 0% due to higher concentrations of NSAIDs in wastewater effluents rather than influents were observed in certain instances. The detection of NSAIDs in sediments and aquatic plants could serve as the important starting step to investigate other means of NSAIDs removal from water. In conclusion, recommendations regarding future studies that could paint a clearer picture regarding the occurrence and ecotoxicological risks posed by NSAIDs in South African aquatic environment are provided.

Solid-phase optimisation for simultaneous determination of thirteen pharmaceuticals in Ethiopian water samples with HPLC-DAD detection: an initial assessment

Pharmaceutical consumption is increasing worldwide as it is essential to treat and prevent health issues but they end up in the environment. However, in many African countries like Ethiopia, the status of these compounds in various environmental samples is not very well known. In this study, a simple method for the extraction and determination of thirteen pharmaceutical compounds of different therapeutic classes in water samples using solid-phase extraction and HPLC-DAD was developed. Different parameters affecting extraction were optimised and obtained as hydrophilic-lipophilic balance (HLB) extraction cartridge, water sample pH of 5, elution solvent of 2% formic acid in water with methanol (20:80%, v/v), a sample volume of 150 mL and addition of 0.5% w/v EDTA in the sample. The limits of detection and quantification of the optimised method were in the range of 0.1-0.8 µg/L and 0.2-2.6 µg/L, respectively. The relative recovery in the spiked environmental water sample was in the range of 70-117% except for amoxicillin and acetylsalicylic acid in influent wastewater. The precision for all ranged from 0.3 to 11%. The proposed method was successfully tested for the detection and quantification of different environmental water samples collected from Addis Ababa, Ethiopia. Trimethoprim, caffeine and albendazole concentrations of 7.8 (1.1), 3.2 (0.4) and 2.1 (0.1) µg/L were quantified in hospital wastewater, respectively. The concentration of norfloxacin was found to be below the limit of quantification in the same water. Trimethoprim and ciprofloxacin were also found in the sewage treatment plant influent sample at a concentration of 0.5 (0.02) and 0.3 (0.01) µg/L, respectively.

Imprinting Technology for Effective Sorbent Fabrication: Current State-of-Art and Future Prospects

In the last 10 years, we have witnessed an extensive development of instrumental techniques in analytical methods for determination of various molecules and ions at very low concentrations. Nevertheless, the presence of interfering components of complex samples hampered the applicability of new analytical strategies. Thus, additional sample pre-treatment steps were proposed to overcome the problem. Solid sorbents were used for clean-up samples but insufficient selectivity of commercial materials limited their utility. Here, the application of molecularly imprinted polymers (MIPs) or ion-imprinted polymers (IIPs) in the separation processes have recently attracted attention due to their many advantages, such as high selectivity, robustness, and low costs of the fabrication process. Bulk or monoliths, microspheres and core-shell materials, magnetically susceptible and stir-bar imprinted materials are applicable to different modes of solid-phase extraction to determine target analytes and ions in a very complex environment such as blood, urine, soil, or food. The capability to perform a specific separation of enantiomers is a substantial advantage in clinical analysis. The ion-imprinted sorbents gained interest in trace analysis of pollutants in environmental samples. In this review, the current synthetic approaches for the preparation of MIPs and IIPs are comprehensively discussed together with a detailed characterization of respective materials. Furthermore, the use of sorbents in environmental, food, and biomedical analyses will be emphasized to point out current limits and highlight the future prospects for further development in the field.

Synthesis of magnetic covalent organic framework molecularly imprinted polymers at room temperature: A novel imprinted strategy for thermo-sensitive substance

Molecularly imprinted polymers (MIPs) with specific selective recognition have shown excellent performance in the rapid and efficient separation and enrichment of targets in complex systems. Unfortunately, it is not suitable for thermosensitive substances with biological functions. To this end, an imine-linked MIPs with covalent organic frameworks and magnetic nanoparticles was developed by using a room temperature synthesis strategy for the purification of Cyaninin-3-O-glucoside (C3G) from black chokeberry. The prepared material recognized C3G through π-π interaction, assisted by hydrogen bond, and will not be disturbed by water environment. The adsorption capacity and equilibrium binding constant were 86.92 mg g^-1 and 1.46 L mg^-1, respectively. Based on this special structure, it can also act as a "protective umbrella" and improve the stability of C3G. Furthermore, it exhibited high selectivity compared with dummy template imprinting technique. After purification, the purity of C3G was obviously improved (from 11.96% to 84.72%). This work provided a new strategy for the selective separation of anthocyanin and a method to develop MIPs for thermosensitive substances.

Optimization and application of hollow fiber liquid-phase microextraction and microwave-assisted extraction for the analysis of non-steroidal anti-inflammatory drugs in aqueous and plant samples

Human consumption of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing, which poses a great risk of pollution by these pharmaceuticals on the aquatic environment. Therefore, this study reports the optimization of microwave-assisted extraction using water as a green solvent and hollow fiber liquid-phase microextraction (HF-LPME) methods followed by high-performance liquid chromatography-high resolution mass spectrometry analysis of NSAIDs in wastewater and aquatic plant, Eichhornia crassipes. The optimized MAE resulted in efficient transfer of selected NSAIDs from plant samples into the aqueous phase yielding the recoveries ranging from 91 to115%. A multivariate approach based on half fractional factorial and central composite design was used during the optimization of HF-LPME. Under the optimized conditions, the maximum enrichment factors for naproxen, fenoprofen, diclofenac, and ibuprofen were 49, 126, 93 and 156, respectively. The overall analytical method recoveries ranged from 86 to 116% while the limits of quantitation for wastewater and plant samples ranged from 0.09 to 0.59 μg L^-1 and from 0.11 to 0.59 μg kg^-1, respectively. The precision of the proposed analytical method which was measured in terms of RSD values did not exceed 5%. Naproxen was the most abundant compound in both wastewater and the Eichhornia crassipes plant samples with concentrations of up to 3.30 μg L^-1 and 10.97 μg kg^-1, respectively. The detection of NSAIDs in Eichhornia crassipes means this plant has the ability to bioaccumulate pharmaceutical load in surface water.

Analysis, occurrence and removal of pharmaceuticals in African water resources: A current status

Pharmaceuticals are organic compounds used in medicines for alleviation of pain. Since 2017, there has been a steady increase on the availability of information on contamination of water resources caused by pharmaceuticals in some African countries. Thus far, most environmental monitoring studies of pharmaceuticals are conducted in South Africa while there is still no available data in majority of the African countries. Therefore, the knowledge on the presence of pharmaceuticals in African water resources is still lacking. In an attempt to provide more information in this aspect, this review article seeks to critically evaluate the progress made thus far by the African scientists in the environmental monitoring and assessment of pharmaceuticals. The most studied groups of pharmaceuticals in Africa are non-steroidal anti-inflammatory drugs, antibiotics, antiretroviral drugs and steroid hormones. Various remediation studies for selected pharmaceuticals in Africa are documented in literature. In the present review, the challenges facing the African researchers or countries on providing more scientific data on the occurrence of pharmaceuticals in water are discussed. Furthermore, the gaps and recommendations for future work are given.