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This work describes a simple and sensitive method for the simultaneous isolation, enrichment, identification and quantitation of selected antiretroviral drugs; emtricitabine, tenofovir disoproxil and efavirenz in aqueous samples and plants. The analytical method was based on microwave extraction and hollow fibre liquid phase microextraction technique coupled with ultra-high pressure liquid chromatography-high resolution mass spectrometry. A multivariate approach via a half-fractional factorial design was used focusing on six factors; donor phase pH, acceptor phase HCl concentration, extraction time, stirring rate, supported liquid membrane carrier composition and salt content. The optimal enrichment factors for emtricitabine, tenofovir disoproxil and efavirenz from aqueous phase were 78, 111 and 24, respectively. The analytical method yielded recoveries in the range of 86 to 111%, and quantitation limits for emtricitabine, tenofovir disoproxil and efavirenz in wastewater were 0.033, 0.10 and 0.53 μg L -1 , respectively. The drugs were detected in most samples with concentrations up to 37.6 μg L -1 recorded for efavirenz in wastewater effluent. Roots of the water hyacinth plant had higher concentrations of the investigated drugs ranging from 7.4 to 29.6 μg kg -1 . Overall, hollow fibre liquid phase microextraction proved to be an ideal tool for isolating and pre-concentrating the selected antiretroviral drugs from environmental samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A technique that combines membrane assisted solvent extraction and molecularly imprinted polymer into a single step format has been successfully developed and evaluated for the extraction of the 16 US-EPA priority polycyclic aromatic hydrocarbons in wastewater samples followed by determination using gas chromatography coupled with time of flight mass spectrometry. The technique involves placing the polymer particles into a hydrophobic polypropylene membrane bag which is in contact with an aqueous donor phase. The technique was optimized for various parameters that include presence of an organic modifier in the donor phase, stirring rate and extraction time. The optimum conditions were 25% of dimethyl sulfoxide as an organic modifier and stirring at 1000 rpm for 120 min. The limits of detection using the technique were in the 0.01-0.45 ng mL -1 range. Linearity values determined in the 10-1 000 ng mL -1 calibration range were all above 0.9972. Extraction efficiencies of the sixt analytes calculated as averages for three spiking concentrations ranged from 62.8 to 96.8% (RSD = 3.1-12.3%). The optimized method was tested for the extraction of polycyclic aromatic hydrocarbons in wastewater samples in the presence of surrogate standards. The developed method showed great reproducibility with inter day repeatability values ranging from 0.6 to 24.9%. The analytes were quantified in the nanogram level showing that the developed technique is a viable alternative in the analysis of trace organic compounds in complex aqueous samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The present paper reports a detailed study that is based on the monitoring of naproxen, ibuprofen, and diclofenac in Mbokodweni River and wastewater treatment plants (WWTPs) located around the city of Durban in KwaZulu-Natal Province of South Africa. Target compounds were extracted from water samples using a multi-template molecularly imprinted solid-phase extraction prior to separation and quantification on a high-performance liquid chromatography equipped with photo diode array detector. The analytical method yielded the detection limits of 0.15, 1.00, and 0.63 μg/L for naproxen, ibuprofen, and diclofenac, respectively. Solid-phase extraction method was evaluated for its performance using deionized water samples that were spiked with 5 and 50 μg/L of target compounds. Recoveries were greater than 80% for all target compounds with RSD values in the range of 4.1 to 10%. Target compounds were detected in most wastewater and river water samples with ibuprofen being the most frequently detected pharmaceutical. Maximum concentrations detected in river water for naproxen, ibuprofen, and diclofenac were 6.84, 19.2, and 9.69 μg/L, respectively. The concentrations of target compounds found in effluent and river water samples compared well with some studies. The analytical method employed in this work is fast, selective, sensitive, and affordable; therefore, it can be used routinely to evaluate the occurrence of acidic pharmaceuticals in South African water resources.

The influence of temperature on the extraction and selectivity of naproxen, ibuprofen, and triclosan by a thin-walled hollow fiber silicone rubber membrane was investigated. Determination of the diffusion coefficients and flux values at 25, 40, and 60 degrees Celsius was undertaken. The diffusion coefficient and flux were found to increase with temperature. It was also observed that at higher temperatures, mass transfer was influenced by the amount extracted in the acceptor phase. However, diffusion from the bulk donor phase through the hollow fiber silicone rubber membrane was shown to control the transport of analytes at lower temperatures. When applied to wastewater, the hollow fiber silicone rubber showed remarkable selectivity toward the analytes. However, at high temperatures, the amount of matrix components extracted also increased slightly. The amount extracted nearly doubled when extraction was performed at 40 degrees Celsius compared to 25 degrees Celsius, indicating that temperature increased the efficiency of the hollow fiber silicone rubber membrane. The application of the technique to municipal wastewater showed remarkable selectivity and reproducibility. The concentrations of these compounds were from 18.4 (1.37 percent) micrograms per liter for triclosan to 1.1 (0.16 percent) micrograms per liter for naproxen in the influent and 2.7 (0.29 percent) micrograms per liter for triclosan to 0.4 (0.01 percent) micrograms per liter for naproxen in the effluent. [ABSTRACT FROM AUTHOR]

In this study, the occurrence in wastewater of two non-steroidal anti-inflammatory drugs (NSAIDs), naproxen and ibuprofen, and one personal care product, triclosan, was assessed using the polar organic chemical integrative sampler (POCIS). The samplers were initially calibrated in the laboratory to obtain sampling rates (Rs) for each target compound followed by deployment in the influent and effluent of Goudkoppies and Northern Wastewater Treatment Plants (WWTPs), South Africa. Exposure was done for 14 days in 2012. High performance liquid chromatography (HPLC) system with ultraviolet (UV) and fluorescence (FLD) detectors was used to analyse POCIS extracts. Laboratory calibration of POCIS yielded Rs values for the three compounds that were between 0.087 and 0.383 ⨏·d-1 in quiescent conditions, and 0.125 and 0.936 ⨏·d-1 in stirred conditions. From the accumulated amounts in field-deployed samplers, estimated freely dissolved concentrations of the studied compounds in wastewater influent ranged from 55.0 to 78.4 μg·⨏-1 and 52.3 to 127.7 μg·⨏-1 in Goudkoppies and Northern WWTPs, respectively. Average concentrations of these compounds in the treated effluent ranged from 10.7 to 13.5 μg·⨏-1 in Goudkoppies WWTP, and 20.4 to 24.6 μg·⨏-1 in Northern WWTP. Analyte removal efficiencies varied between 68 and 86% in Goudkoppies WWTP and 61 and 82% in Northern WWTP. Grab samples processed by SPE method yielded higher analyte concentrations (up to three-fold) as compared to POCIS-derived estimates. This discrepancy was attributed to SPE's ability to extract both the free dissolved, and particle sorbed fractions of the contaminants. [ABSTRACT FROM AUTHOR]

Chromium (Cr) is an important raw material in some chemical industries including paint, pigments, textiles, leather tanning, steel fabrication, electroplating, cement preservation, and canning industries. Once in the environment, Cr exists in various oxidation states depending on pH and concentration. Trivalent [Cr(III)] and hexavalent [Cr(VI)] forms are the most common with Cr(VI) being the most toxic to biota. The review discusses various types of polymeric sorbents that have been prepared for the extraction of Cr(VI) from environmental samples, mostly aqueous samples. Sorbents are categorized into biosorbents, hybrid sorbents, synthetic polymeric, and modified natural polymeric sorbents. Most of the emphasis will be on the advantages and disadvantages of different synthetic polymeric sorbents. Important parameters that define the performance of the sorbents, that is, binding capacity, equilibration time, optimum sample pH, and selectivity, are compared. [ABSTRACT FROM AUTHOR]

• Recovery of Pd(II), Ir(III) and Rh(III) using functionalised bentonite was studied. • Bentonite was successfully functionalised by brewer's spent yeast. • Maximum adsorption capacity for all elements was achieved at pH 2 and 10 g L−1. • The Fe-Pd interaction in the presence of other ions increased the Pd(II) uptake. • Yeast-functionalised bentonite can successfully recover Pd(II), Ir(III) and Rh(III). The scarcity of precious elements such as Pd(II), Ir(III) and Rh(III) has been increasing over the years hence, their recovery from wastewaters using efficient and cheap recovery techniques is becoming more important. In this study, the spent yeast collected after brewing was used to functionalise bentonite clay material to obtain very cheap material for recovery. The functionalised bentonite was characterised using Fourier transform infrared (FTIR) spectroscopy and element analyser. The textural properties of the natural and functionalised bentonite were determined. The effect of adsorbent dosage, pH, concentration, contact time and competing ions on the adsorption of Pd(II), Ir(III) and Rh(III) by yeast-functionalised bentonite was determined. The adsorbent dosage of 10 g L−1 and 360 min were chosen as optimum for this study. The pH of 2 was used since; it is the typical pH of the processing plant wastewater under investigation. The adsorption of Pd(II) and Ir(III) decreased as the pH increased whilst that of Rh(III) increased with pH. The adsorption of Pd(II) increased with concentration and this was attributed to the ability of Pd(II) to adsorb on different active sites of the adsorbent. This was substantiated by the adsorption isotherm study since, the adsorption of Pd(II) onto the adsorbent was best described by the Freundlich isotherm, meaning that the adsorption occurs on different active sites. Beyond 2 mg L−1, the adsorption capacity of Ir(III) and Rh(III) remained the same. In the presence of other ions, Pd(II) adsorption increases due to the synergistic Fe-Pd interaction but, the adsorption of Ir(III) and Rh(III) decreased by 57 and 17%, respectively. Therefore, to significantly recover Ir(III) and Rh(III), the old adsorbent which contains a significant amount of other elements should constantly be replaced by the new one and as other elements decrease, the adsorption of Ir(III) and Rh(III) will increase. The yeast-functionalised bentonite is a potential cheap adsorbent for the adsorption of precious elements. [ABSTRACT FROM AUTHOR]

• NSAIDs are predominant water pollutants and their removal strategies are examined. • Several adsorbents reported for NSAIDs removal from water are re-usable. • Toxicity of some NSAIDs degradation products in aquatic environment is not known. • Adsorbents with higher surface area resulted in greater adsorption capacities. • Few plant species have the ability to remove selected NSAIDs from water. In the past few decades, there has been a rapid growth in the number of published articles that have focused on the environmental monitoring of non-steroidal anti-inflammatory drugs (NSAIDs). This is due to their extensive usage for the treatment of various diseases such as arthritis, musculo-skeletal pain and other various acute pains, because of their availability over the counter without a medical prescription. NSAIDs consumption is followed by excretion through fecal matter and urine which increases their concentration in the aquatic environment. Review articles focusing on the occurrence, fate, and removal of pharmaceuticals in the water environment have been reported. This review focusses on adsorbents and various ways of NSAIDs reduction in the environment that include activated carbon, ligninolytic enzymes, graphene-based adsorbents, molecularly imprinted polymers, electrochemical methods, sonochemical processes and photocatalytic degradation. The applicability of each adsorbent in removing NSAIDs from environmental surface water are deliberated in this review. Generally, it is observed that many adsorbents and processes are yet to be investigated for removal of NSAIDs in the large scale such as wastewater treatment plants. Other remedial approaches such as constructed wetlands have shown great potential for elimination of NSAIDs in wastewater effluent and are also discussed in this review. Also, the attainments and challenges, as well as views for future studies, are outlined and discussed in the current review. [ABSTRACT FROM AUTHOR]

Ketoprofen is a nonsteroidal anti-inflammatory drug widely consumed by humans as it possesses analgesic activities. A selective molecularly imprinted polymer (MIP) for ketoprofen was synthesized and applied as a solid-phase extraction sorbent. MIP was synthesized using 2-vinylpyridine, ethylene glycol dimethacrylate, 1,1′-azobis(cyclohexanecarbonitrile), toluene/acetonitrile (9:1, v/v), and ketoprofen as a functional monomer, cross-linker, initiator, porogenic mixture, and template, respectively. The polymerization was performed at 60 °C for 16 h, and thereafter the temperature was increased to 80 °C for 24 h to achieve a solid monolith polymer. Nonimprinted polymer was synthesized in a similar manner with the omission of ketoprofen. Characterization with thermogravimetric analysis and X-ray diffraction showed that the synthesized polymers were thermally stable and amorphous. Solid-phase extraction cartridges packed with MIP were used with high-performance liquid chromatography for quantitative analysis of ketoprofen in wastewater. The analytical method gave detection limits of 0.23, 0.17, and 0.09 μg/L in wastewater influent, effluent, and deionized water, respectively. The recovery for the wastewater influent and effluent spiked with 5 μg/L of ketoprofen was 68%, whereas 114% was obtained for deionized water. The concentrations of ketoprofen in the influent and effluent samples were in the ranges of 22.5–34.0 and 1.14–5.33 μg/L, respectively. Overall, the analytical method for the analysis of ketoprofen in wastewater was rapid, affordable, accurate, precise, sensitive, and selective. [ABSTRACT FROM AUTHOR]