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Concentrations of pharmaceuticals (sulfamethoxazole, sulfamethoxazole hydroxylamine, prednisolone and ivermectin) showed good correlation with the number of COVID-19 infections in South Africa.

This study aimed to assess the impact of the eThekwini Municipality reforestation project on the quality of the soil within the reforestation sites, and water from the nearby rivers (White and Black Mhlasini Rivers) situated at the reforested Buffelsdraai area in KwaZulu-Natal, South Africa. This was the first evaluation of the effect of reforestation on the reduction of selected organic pollutants to be conducted in this area. The sixteen polyaromatic hydrocarbons analysed are on the Environmental Protection Agency (EPA) list of priority pollutants. The soil and sediment samples were extracted using ultrasonication, and liquid-liquid extraction was utilised for the water samples. Gas chromatography mass spectrometry (GCMS) was used to analyze the PAHs. PAH recoveries ranged between 60 and 110%. The PAH LOD values were between 0.30 and 0.69 μg g

A simple spectrophotometric method for the determination of low levels of the orthophosphate (PO43-) in environmental water systems is reported. The method is based the formation of the phosphomolybdate from the condensation of molybdate and orthophosphate in aqueous acid medium followed by reduction with sodium thiosulphate to form phosphomolybdenum blue. The system obeys Beer’s law at 880 nm (λmax) in the 0.005–0.06 mg P mL-1 phosphate concentration range. Molar absorptivity, Sandell’s sensitivity and correlation coefficient values for the determination were 57526 L mol-1 cm-1, 0.2835 μg cm-2 and 0.9948 respectively. The limit of detection was 2.213 x 10-3 mg P mL-1. The results of PO43- determination in water samples obtained using the spectrophotometric method developed in this study, compare favourably with those generated using the Murphy and Riley method which is commonly used for this analysis. Therefore, the study ably demonstrates the suitability of the present spectrophotometric method for analysis of the orthophosphate in environmental water samples.

This study focuses on the sorption efficiency of porewater–sediment of eight selected polychlorinated biphenyls (PCBs) most monitored in the environment as recommended by the Environmental Protection Agency. Five river sediment samples were collected along the Umgeni River of KwaZulu-Natal province of South Africa that contained different soil contents. The Walkley–Black method was employed for the determination of soil organic matter in the sediments, while sediment mineralogy and morphology, as well as elemental composition, were evaluated using powder X-ray diffraction and scanning electron microscopy equipped with energy-disperse X-ray, respectively. The sorption studies between porewater and sediment systems were carried out using batch adsorption experiments. The results showed that sediment samples containing high clay and silt content (13.90%, 30.43% and 18.58%, 19.93%) (site AWW and IDI) have the highest sorption percentage between 65.86–89.81% and 61.39–70.43%, respectively, for all the PCBs, while sites IDO and BL with high sand content (86.29% and 85.20%) sorbed the least amount of PCBs (32.32–53.06% and 43.23–59.77%, respectively). Among the sediment physicochemical parameters, soil organic matter was observed to correlate positively and play an important role in the sorption of PCBs. Also, a decrease in the ratio of Si:(Al + Fe) was noticed to have a positive impact on the sorption of PCBs. This is the first study done on this river to critically evaluate the porewater–sediment distribution and transportation of PCBs. Sorption efficiency of sediments of known physicochemical properties similar to this study area can be predicted by the sorption results of the present study.

The leaves of Polydora serratuloides, with the synonym Vernonia perrottetii are widely used as purgative agents for gastrointestinal problems, and other members of Vernonieae have been used in Afri...

The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl (PCB) congeners between aqueous solution and soil particles with different grain sizes was studied. The mineral properties of a model soil sample were determined, and Brunauer-Emmett-Teller (BET) adsorption-desorption isotherms were employed to observe the surface characteristics of the individual modeled soil particles. Batch adsorption experiments were conducted to determine the sorption of PCBs onto soil particles of different sizes. The results revealed that the sorption of PCB congeners onto the soil was dependent on the amount of soil organic matter, surface area, and pore size distribution of the various individual soil particles. Low pH favored the sorption of PCBs, with maximum sorption occurring between pH6.5 and 7.5 with an equilibration period of 8hr. Changes in the ionic strength were found to be less significant. Low temperature favored the sorption of PCBs onto the soil compared to high temperatures. Thermodynamic studies showed that the partition coefficient (Kd) decreased with increasing temperature, and negative and low values of ΔH° indicated an exothermic physisorption process. The data generated is critical and will help in further understanding remediation and cleanup strategies for polluted water.

The role of initial aqueous humic acid concentrations (dose), as well as secondary environmental conditions on the sorption of PCB congeners PCB 28, 52, 77, 101, 105, 138, 153, and 180 onto soil particle grain sizes, was investigated in this study. Scanning electron microscopy equipped with energy dispersive X-ray and Fourier transform infrared spectroscopy were used for the internal morphology and qualitative elemental analysis, as well as identification of possible functional groups found in commercial HA. Batch adsorption experiments were used for sorption studies. The results showed that the sorption of PCBs onto soil decreased with an increase in the aqueous HA concentrations. The adsorption of the selected PCBs onto the soils was found to decrease with an increase in the solution pH of humic acid. Thermodynamic studies showed that the partition coefficient values increased with an increase in solution temperature. All the standard free energy were negative indicating the spontaneity and feasibility of the sorption process with positive and high enthalpy and entropy values of the system. The sorption was best fitted with the Freundlich isotherm with the intensity parameter 1/n found to be greater than 1. The outcome of this study revealed that secondary pollution of river water may possibly be altered depending on variations in the environmental conditions such as pH and temperature. The presence of organic pollutants in alkaline soils having less organic matter content could increase the chances of leaching of organic pollutants causing groundwater contamination.

In this study, various low cost mesoporous silica (MS) were synthesised from elephant grass (EG) a biowaste material often regarded as a weed, by varying synthesis conditions, such as temperature and surfactant concentration (cetyltrimethyl ammonium bromide (CTAB)), thus revealing the transformation of mesoporous silica from silica nanoparticles to silica nanotubes. MS obtained were extensively characterised. Highly porous silica nanoparticles (SNP) were obtained at 2 wt. percent of surfactant to silica and at 45 wt. silica nanotubes (SNT) were obtained. It was observed that 600 °C was the optimum temperature in MS synthesis as it gave higher surface area and an all-round better textural property in the sorption of methylene blue (cationic dye) and methyl orange (anionic dye) from wastewater. Batch adsorption was carried out to determine the effect of time, temperature, initial concentration, pH and adsorbent dose. SNP had a higher qm value of 123.5 mg/g for MB and 83.3 mg/g for MO which may be attributed to its larger surface area. Adsorption mechanism was through ion exchange and pore filling. Thermodynamic study revealed the adsorption process was exothermic. This study showed the transformation of EG into highly efficient sorbents with desorption studies showing that adsorbents could be reapplied in adsorption.

As-synthesised MCM-48 (ASM48), graphene oxide encapsulated MCM-48 (M48GO) and reduced graphene oxide encapsulated MCM-48 (M48G) was synthesised and applied in remediation of caffeine (CAF) and phenacetin (PHE) from aqueous solution. Effects of surfactant template (cetyltrimethylammonium bromide) on MCM-48 on the removal of CAF and PHE from wastewater samples was also investigated. Adsorbents were characterized with the following techniques; FTIR, TGA, XRD, SEM, TEM, BET, EA. Elemental analysis revealed ASM48 had improved hydrophobic properties and the successful synthesis of M48GO and M48G. All adsorbents were applied in batch sorption studies of CAF and PHE to determine the effects of adsorbent dose, pH and initial concentration. Adsorption mechanism was through π-π interaction, EDA interaction and hydrophobic effects. Sorption kinetics showed that the data fitted pseudo-second order and intraparticle diffusion models. Equilibrium data obtained fitted the Freundlich and Langmuir adsorption isotherm. M48G had the best adsorption capacity of 153.8 and 212.7 mg/g for CAF and PHE, respectively and ASM48 showed significant adsorption which was attributed to increased hydrophobicity created by the surfactant template in ASM48. Thermodynamic studies revealed adsorption process as spontaneous and exothermic. Desorption studies revealed that adsorbents could be regenerated and reused for adsorption.

In this study, ASM41 (as-synthesised MCM-41), MCM-41, MCM-41 encapsulated with graphene oxide (MCM-41-GO) and reduced graphene oxide (MCM-41-G) were fabricated and utilized in the remediation of acetaminophen and aspirin from water. A surfactant template (cetyltrimethylammonium bromide) was added to ASM41 to make it more hydrophobic and its effects on the remediation of acetaminophen and aspirin from wastewater was studied. To further improve the adsorption capacity of the adsorbent, MCM-41 was encapsulated with GO and G which also aided in easy separation of the adsorbent from the aqueous solution. Comparative studies of the adsorption of acetaminophen and aspirin on all four adsorbents were investigated. Batch adsorption studies of acetaminophen and aspirin were carried out to determine the effects of pH, initial concentration, time and adsorbent dose. Adsorption mechanism was through EDA, π-π interactions, and hydrophobic effects. Data from sorption kinetics showed ASM41 had the highest q m value for aspirin (909.1 mg/g) and MCM-41-G had the highest q m value for acetaminophen (555.6 mg/g). The significant adsorption by ASM41 can be attributed to increased hydrophobicity due to the retention of the surfactant template. Thermodynamic studies revealed the adsorption process as spontaneous and exothermic. Desorption studies revealed that adsorbents could be regenerated and reused for adsorption.

Incorporation of graphene/graphene oxide on a low-cost support has been established to improve adsorption performance. This study reports the synthesis of silica nanotubes (SNT) from elephant grass, its encapsulation by reduced graphene oxide (RGO)/graphene oxide (GO) and its application as a highly efficient adsorbent for the remediation of sulfamethoxazole from wastewater. The SNT was synthesized and encapsulated with GO and RGO, to obtain silica nanotubes graphene oxide (SNTGO) and silica nanotubes reduced graphene oxide (SNTG), respectively. The adsorbents were characterized with FTIR, CHN elemental analysis, thermogravimetric analysis, XRD, field emission scanning electron microscopy, and transmission electron microscopy. The FTIR, elemental analysis, and XRD results confirmed successful synthesis of the materials. SNTGO had an adsorption capacity of 125 mg/g, which increased to 248 mg/g when it was reduced to SNTG in the adsorption of sulfamethoxazole. The pseudo-second-order model best described th...

Ionic liquid modified sorbent materials derived from peanut shell were prepared and used in the sorption of Congo red (CR) and reactive blue 4 (RB) dyes from aqueous solution. 1-methyl-3-decahexyl imidazolium ionic liquid (IL) was used to modify peanut shell (NS) and activated carbon (AC) from NS, to produce IL modified peanut shell (ILNS) and IL modified AC (ILAC), respectively. The adsorbents were characterised by fourier transform infrared (FTIR), Brunauer−Emmett−Teller (BET), x-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of sorbent dosage, initial solution pH and contact time (min) were evaluated. Adsorption was pH dependent, the modified materials (ILNS and ILAC) showed improved adsorption capacities of 136.4 and 150.0 mg g−1 for CR and 290.0 and 364.4 mg g−1 for RB respectively. Adsorption followed pseudo-second order. Also, adsorption of CR and RB onto ILAC followed the Freundlich isotherm, while ILNS was described by Freundlich and Langmuir.

The occurrence of eight pharmaceuticals was monitored during four seasons (spring, summer, autumn, and winter) along a 250-km stretch of the Msunduzi and Mgeni rivers in KwaZulu-Natal, South Africa. This paper describes an optimized method for the determination of nonsteroidal anti-inflammatory drugs (NSAIDs) in sediments. The method combines ultrasonic, centrifuge, and gas chromatography-mass spectrometry for the detection of these drugs in solid samples. Most of the parameters that affect the extraction step were optimized. Solid samples were placed in a centrifuge tube and extracted with ethyl acetate:acetone (1:1, two cycles), followed by clean-up with Oasis HLB cartridge and derivatization with N, O-bis(trimethylsilyl) trifluoroacetamide (BSTFA). Satisfactory recoveries were obtained ranging from 66 to 130%, depending on the analyte. Precision expressed as RSD (%) (n = 3) was less than 20% for all analytes. The LODs and LOQs were in the range of 0.024 to 1.90 ng g−1 which allowed to be applied in the analysis solid samples in Msunduzi and Mgeni rivers. In the solid samples analyzed, NSAID concentration ranged from not detected to 221 ng g−1.

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There is growing interest in determining the unidentified peaks within a sample spectra besides the analytes of interest. Availability of reference standards and hyphenated instruments has been a key and limiting factor in the rapid determination of emerging pollutants in the environment. In this work, polar compounds were silylated and analyzed with gas chromatography mass spectrometry (GC-MS) to determine the abundant fragments within the single ion monitoring (SIM) mode and methodology. Detection limits and recoveries of the compounds were established in river water, wastewater, biosolid and sediment matrices. Then, specific types of polar compounds that are classified as emerging contaminants, pharmaceuticals and personal care products, in the environment were targeted in the Mgeni and Msunduzi Rivers. We also performed suspect and non-target analysis screening to identify several other polar compounds in these rivers. A total of 12 compounds were quantified out of approximately 50 detected emerging contaminants in the Mgeni and Msunduzi Rivers. This study is significant for Africa, where the studies of emerging contaminants are limited and not usually prioritized.

is study investigated the presence and distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in soil collected along the banks of the Umgeni River, one of the largest rivers in the province of KwaZulu-Natal, South Africa. e analysis was performed using gas chromatography-mass spectrometry (GC-MS). e results showed that the levels of OCPs ranged from 3.58±0.09 ng/g for hexachlorobenzene (HCB) to 82.65±2.82 ng/g for HCH, with an individual mean concentration of 24.33±2.00 ng/g dry weight (dw). e levels of PCBs ranged from 10.46 ng/g for PCB105 to 89.46 ng/g for PCB180, with an average PCB value of 25.47±1.26 ng/g, dw. e highest levels of OCPs and PCBs were found at Northern Wastewater Treatment Plant (mean OCP: 32.39±3.97 ng/g and PCB: 67.87±1.67 ng/g). e two most abundant contaminants in the river were endrin and PCB180. Keywords : Umgeni River, bank soil, OCPs, PCBs, gas chromatography mass spectrometry

In this study, citric acid (CA) grafted MCM-41 (SCA-MCM-41) was synthesized for improvement of its adsorptive capacity for methylene blue (MB), malachite green (MG) and brilliant green (BG). Characterization of the adsorbent was carried out using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), elemental analysis (EA), X-ray diffraction analysis (XRD), textural analysis, thermo-gravimetric analysis (TGA), solid state nuclear magnetic resonance analysis (SSNMR) and fourier transform infrared analysis (FTIR). MB, MG and BG adsorption studies were carried out on citric acid modified MCM-41, varying parameters such as initial dye concentration, pH, adsorbent dose, contact time and temperature. The maximum adsorption capacity of the modified material improved considerably for all the dyes with a basic pH and temperature of 25 °C for all the adsorbates. The qm values obtained were 204.08 mg/g, 334 mg/g and 227 mg/g for MB, MG and BG, respectively. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models were used in analyzing equilibrium data. The adsorption kinetics favoured the pseudo-second-order model. Adsorption of the dyes into SCA-MCM-41 was spontaneous and exothermic.

Adsorption studies were carried out to determine the efficiency of kaolin modified with a novel long chain ionic liquid (IL) 1-hexyl, 3-decahexyl imidazolium. Synthesis of IL was carried out and characterised with NMR and fourier transform infrared (FT-IR) spectroscopy. Kaolin was modified with IL to form hydrophobic kaolin (modified–kaolin) by adding IL in excess of the cation exchange capacity of kaolin. Modified–kaolin was characterised using FT-IR, x-ray diffraction (XRD), Brunauer−Emmett−Teller (BET), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Modified–kaolin was used in column and batch adsorption studies for phenanthrene and acid red dye. Modified–kaolin was an efficient material for the removal of phenanthrene and acid red dye. For column studies, the adsorption capacity, depth of exchange zone, time required for the pollutant to move through the exchange zone which is the height of the adsorbent in the column and adsorption rates were investigated using the Adams-Bohart, Yoon-Nelson model flow and Thomas sorption model. Column adsorption capacity at the same flow rate (5.0 mL min−1) and different concentrations (50, 100 and 200 mg L−1) for phenanthrene were 222.9, 611.8 and 1093.5 mg g−1, while that of acid red dye were 877.0, 1337.4 and 1350.7 mg g−1, respectively. Thomas and Yoon–Nelson models best explained the column studies. Data from both batch studies fitted well to pseudo-second order. The Langmuir isotherm had the best fit with an adsorption capacity of 842.7 mg g−1 for dye and the Freundlich isotherm best described phenanthrene with an adsorption capacity of 188.9 mg g−1.

BACKGROUND The global use of antibiotics has become a serious concern because of its variety of potential adverse effects when present in the environment. Acute and chronic toxicity, impact on aquatic organisms, disruption of microbial populations, and dissemination into antibiotic-resistant genes have reportedly been linked to pharmaceuticals. Therefore, the aim of this study was to investigate the mechanism of remediation of some selected pharmaceuticals in aqueous medium on ionic liquid modified biomass. RESULTS The mechanism of sorption of pharmaceuticals on biomass and biomass modified with an ionic liquid (IL) was investigated. Kigelia pinnata (KP) was modified with IL to form modified biomass (KP-IL). The pharmaceuticals investigated were ibuprofen (IBU), ketoprofen (KET), ampicillin (AMP) and diclofenac (DCL). Optimum adsorption was at pH 2.5 for AMP and pH 5 for IBU, KET and DCL. Sorption data for all the pharmaceuticals were best described by pseudo-second-order kinetics and the Langmuir adsorption isotherm. Maximum sorption capacities of 251.2, 197.1, 276.8 and 73 mg g−1 were obtained for KET, DCL, IBU and AMP, respectively. CONCLUSION The study showed that KP-IL is a good material for the remediation of pharmaceuticals, and the adsorption capacity was far better than that of the unmodified KP and biomasses previously reported in literature. © 2016 Society of Chemical Industry

A new facile ionic liquid mediated proficient method is developed for the synthesis of structurally new thiazepine and oxazepine derivatives of thiazolidine 2,4-dione. This protocol proceeds through, one-pot three component reaction between fused cyclic ketone, substituted aromatic aldehyde, 2-amino phenol and 2-amino thiobenzene at room temperature to yield structurally new derivatives.

Organochlorinated pesticide (OCP) concentrations were evaluated in sediment, soil and surface water of the Msunduzi River as well as the influent, effluent and biosolids from the Darvill wastewater treatment plant (WWTP) of Pietermaritzburg, South Africa. Samples were extracted with dichloromethane using an ultra-sonication method, and cleaned up using multilayered silica gel and analysed using gas chromatography-mass spectrometry. The results showed that all 13 selected OCPs were detected in all the environmental media as well as in the wastewater treatment plant samples. The results revealed that the OCP concentrations along the sites varied based on the anthropogenic activities of the area. The influent of the Darvill WWTP and Du Toit (DUT) site were found to be the most polluted sites. The results from the winter sampling showed highest concentrations of OCPs compared to the spring season. Sediment was found to contain significant amounts of all the selected OCPs with water samples containing the lowest concentrations for both winter and spring seasons. Among the OCPs evaluated, dichlorodiphenyltrichloroethane (DDT) and its metabolites were predominant in all.

Water pollution by pharmaceuticals is a global issue and its remediation is important. To overcome this, we synthesised super hydrophobic nanoporous 3-dimensional ordered nanomaterials with multi-functional binding chemistry for highly efficient adsorption of estrogen (17β-estradiol). Graphene oxide (GO) was synthesised via Tours method and methoxylether polyethylene glycol (mPEG) was covalently introduced onto GO surface via facile amidation mild process to give GO-mPEG. GO-mPEG was anchored on nanoporous SBA-15 and homogenously reduced in-situ to SBA-rGO-mPEG. XRD analysis confirmed successful synthesis of SBA-15 and cross-linked GO/rGO-mPEG on SBA-15 surface. Image analysis revealed the architecture of SBA-15 as porous 3-dimensional silica network and presence of interwoven/crosslinked thin-films of GO-mPEG on SBA-15 surface. EDX mapping/elemental analysis showed expected elements were present. FTIR and textural analysis revealed the presence of different functional groups and high surface area as well as porosity, respectively. Optimal molar ratio experiments showed that 0.5SBA-rGO-mPEG had the highest sorption capacity. The relatively large surface area, 3-dimensional nanoprous silica structure and excess of polyamide/amido-carbonic functional groups on nanocomposites were suited for adsorption of 17β-estradiol. Equilibrium time was 30 min and effect of pH on adsorption was negligible. Sorption kinetic process of SBA-rGO-mPEG suited the pseudo-second-order model and equilibrium data fitted both Freundlich and Langmuir models. Qm values of 57.1, 78.5, 102.6 and 192.3 mg/g was recorded for SBA-GO, 0.1SBA-rGO-mPEG, 0.25SBA-rGO-mPEG and 0.5SBA-rGO-mPEG, respectively. H-bond, hydrophobic and π−π interactions were the sorption mechanism of SBA-rGO-mPEG after detailed analysis of data. Adsorbents was regenerated/re-used after 4 cycles with high remediation from environmental/real water samples.

The importance of improving adsorbent's adsorption efficiency in organic pollutants has been reported by many researchers. Surfactant-based modified adsorbents were a tasteful choice. As a result, the use of surfactants as a modifier for removing organic pollutants has shown to play a very big role in enhancing the adsorption efficiency of different materials. Ionic liquids are receiving extensive interest as green multipurpose compounds, primarily as a replacement for traditional chemicals that are used in many chemical processes. This work gives a brief bibliometric analysis of application of ionic liquid from 1930 to 2017, documents were collected from Scopus database and keywords from the abstracts and titles were analyzed using VOSviewer software. Furthermore, the work presents a review of conventionally known surfactants and the recent likelihood of ionic liquids for modifying adsorbents for adsorption of organic pollutants. Over the period of years between 1930 and 2017, 13,144 documents were published on the application of ionic liquids. VOSviewer software further confirms that adsorption is one of the leading areas in applications of ionic liquids. Review also showed that ionic liquid is a good modifier of adsorbents.

The adsorption of sulfamethoxazole (SMZ) and ketoprofen (KET) using carbon nanotubes (CNTs) and CNTs modified with ionic liquids (ILs) was investigated. Two ionic liquids (1-benzyl, 3-hexyl imidazolium, IL1 and 1-benzyl, 3-decahexyl imidazolium, IL2) were synthesized, and characterized by nuclear magnetic resonance (1H and 13C NMR) and high resolution-mass spectrometry (HR-MS). CNTs and modified CNTs were characterized using FT-IR, X-ray diffraction (XRD), surface area and porosity analysis, thermal gravimetric analysis (TGA), Zeta potential, Raman and scanning electron microscopy (SEM). Kinetics, isotherm and computational studies were carried out to determine the efficiency and adsorption mechanism of SMZ and KET on modified CNTs. A density functional theory (DFT) method was applied to shed more light on the interactions between the pharmaceutical compounds and the adsorbents at the molecular level. The effects of adsorbent dosage, concentration, solution pH, energetics and contact time of SMZ and KET on the adsorption process were investigated. The adsorption of SMZ and KET on CNTs and modified CNTs were pH dependent, and adsorption was best described by pseudo-second-order kinetics and the Freundlich adsorption isotherm. Ionic liquid modified CNTs showed improved adsorption capacities compared to the unmodified ones for both SMZ and KET, which is in line with the computational results showing performance order; CNT+KET/SMZ

Organochlorine pesticides (OCPs) were analysed in surface water, pore water and surface sediment samples collected from the uMngeni River, which is one of the largest rivers in the province of KwaZulu-Natal, South Africa. Liquid-liquid extraction was used to extract the analytes from water and pore water samples and soxhlet extraction was used to extract sediment samples with subsequent florisil clean-up and gas chromatography-mass spectrometry (GC-MS) analysis. Twelve selected OCPs were analysed and their total concentrations were found to range from 8.04–21.06 ng/mL, 36.06–188.43 ng/mL and 148.17–554.73 ng/g in unfiltered surface water, unfiltered pore water and surface sediment (dry weight (dw)), respectively. The results indicated that the concentrations of these selected pesticides were far higher in sediment (72%) than in pore water (25%) and water (3%). The most polluted sites were Northern Wastewater Treatment influent (NWTI) for water (Σ12OCP = 19.41 ± 1.43 ng/mL) and Northern Wastewater Treatment effluent (NWTE) for pore water (Σ 12 OCP = 166.23 ± 7.16 ng/mL) and sediment (Σ 12 OCP = 495.21 ± 32.38 ng/g). The most abundant individual OCPs and their average concentrations in general in the river were p,p′-DDE in unfiltered water (1.62 ±0.22 ng/mL) and unfiltered sediment pore water (17.09 ±7.96 ng/mL), and endrin in surface sediment (55.57 ± 19.01 ng/g, dw). Keywords : uMngeni River, pore water, sediment, organochlorine pesticides, gas chromatography-mass spectrometry

The paucity of information on the occurrence of pharmaceuticals in the environment in African countries led the authors to investigate 8 acidic pharmaceuticals (4 antipyretics, 3 antibiotics, and 1 lipid regulator) in wastewater, surface water, and sediments from the Msunduzi River in the province of KwaZulu-Natal, South Africa, using solid-phase extraction (SPE) and liquid chromatography–mass spectrometry (LC/MS). The method recoveries, limits of detection (LOD), and limits of quantification were determined. The method recoveries were 58.4% to 103%, and the LODs ranged between 1.16 ng/L and 29.1 ng/L for water and between 0.58 ng/g and 14.5 ng/g for sediment. The drugs were all present in wastewater and in most of the surface water and sediment samples. Aspirin was the most abundant pharmaceutical observed, 118 ± 0.82 μg/L in wastewater influent, and the most observed antibiotic was nalidixic acid (25.2–29.9 μg/L in wastewater); bezafibrate was the least observed. The distribution pattern of the antipyretic in water indicates more impact in suburban sites. The solid–liquid partitioning of the pharmaceuticals between sediment and water, measured as the distribution coefficient (log KD) gave an average accumulation magnitude of 10× to 32× in sediments than in water. The downstream distribution patterns for both water and sediment indicate discharge contributions from wastewater, agricultural activities, domestic waste disposal, and possible sewer system leakages. Although concentrations of the pharmaceuticals were comparable with those obtained from some other countries, the contamination of the present study site with pharmaceuticals has been over time and continues at present, making effective management and control necessary. Environ Toxicol Chem 2016;35:36–46. © 2015 SETAC

The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53–128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21–610.45 ng/g dw at the Du Toit sampling site and 30.86–444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53–397.75 ng/g dw at the Msunduzi Town sampling site and 20.84–443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68–22.37 and 2.53–35.69 ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.

The removal of amaranth dye using montmorillonite modified with an ionic liquid (IL) was investigated. An ionic liquid (1-methyl, 3-decahexyl imidazolium) was synthesised, and characterised by nuclear magnetic resonance (1H and 13C NMR), Fourier transform infrared (FT-IR) spectroscopy, high resolution mass spectroscopy (HR-MS) as well as thermal gravimetric analysis and differential thermal (TGA/DCS) analysis. The ionic liquid was thereafter used to modify sodium montmorillonite (Na+-Mt) to form a hydrophobic montmorillonite that has a positively charged surface, by adding IL in excess of the cation exchange capacity (CEC) of Na+-Mt. Energy dispersive X-ray analyser (EDX) was used to determine the chemical composition of Na+-Mt. Modified montmorillonite (Mt-IL) and Na+-Mt was characterised using FT-IR, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) method, and used in the adsorption study of an anionic amaranth dye. A higher CEC of the Mt-IL (112 meq per 100 g) than Na+-Mt (89 meq per 100 g) was observed. The effects of sorbent dosage, dye concentration, solution pH and contact time were investigated in order to determine optimal experimental conditions. Optimum adsorption was obtained at pH 2 and adsorption data was better described by the pseudo-second-order kinetics and Langmuir adsorption isotherm. A maximum adsorption capacity of 263.2 mg g−1 was calculated. The thermodynamic parameters ΔG°, ΔH° and ΔS° were also investigated at temperatures of 313, 303 and 293 K. Column studies were performed on the modified material and the data generated was applied to the Thomas model where high column adsorption capacities of 393.7, 580.9 and 603.6 mg g−1 at different concentrations were obtained.

A new and straightforward synthetic method was developed for the facile synthesis of heterocycle-fused pyridine derivatives in aqueous media from Knoevenagel condensation between an aromatic aldehyde and an active methylene compound. This was followed by Michael type addition of a ketone to the activated double bond of the arylidene via intramolecular cyclization in the presence of diamine functionalized [N-(2 amino ethyl)-3-amino propyl trimethoxy silane (AAPTMS)] mesoporous ZrO2 (AAPTMS/m-ZrO2) to synthesize fused pyridines in high yield. This one-pot conversion, which involves multiple steps and requires no toxic/organic solvents, produced new C–C and C–heteroatom bonds with all reactants efficiently utilized.

A one-pot efficient synthetic protocol is described for the synthesis of carbapenem chalcone derivatives using AAPTMS@MCM-41 heterogeneous catalyst. Various substituted aromatic aldehydes were attached to highly chiral and reactive carbapenem using this approach. The cytotoxic activity evaluation of all synthesized compounds was performed against lung cancer cell lines (A-549) and breast cancer cell lines (MCF-7) using the MTT assay. Among the tested compounds, compound CPC-2 showed better activity against MCF-7 cell lines with an IC50 value 2.52 μM mL(-1); whereas compound CPC-4 showed good activity against A-549 cell lines with an IC50 value 1.59 μM mL(-1). In order to support the observed activity profiles, the representative compounds were flexibly docked into the active sites of the Anaplastic Lymphoma Kinase (ALK) enzyme and the Estrogen receptor (ERβ). The most active anticancer compounds exhibited stronger binding affinities for proteins.

The adverse effect of organic pollutant such as dyes and pharmaceuticals on aquatic life is of great concern. Thus, in this work, a highly hydrophobic composite made up of graphene oxide (GO) and ionic liquid (IL) was synthesized for the removal of reactive blue 19 (RB19) and sulfamethoxazole (SMZ). GO was first synthesized with the Tour method and the long chain C14 imidazolium IL through a green technique. 13C, 1H NMR and HRMS were used to determine the structure of the synthesized ionic liquid. GO-IL was produced by co-precipitation of GO and IL. FTIR confirmed the presence of the new functional groups on GO-IL. XRD confirmed GO synthesis and the crystalline nature of GO-IL. SEM and TEM confirmed the sheet like morphology of GO and GO-IL and showed enmeshment of IL in the lateral GO sheets. The experimental conditions for the adsorption of RB19 on GO was at 25℃, with pH 2.04 and 3 g/L dose of adsorbent. For GO-IL the optimum dose of 0.5 g/L and 0.9 g/L at pH of 4.01 and 6.28 for RB19 and SMZ adsorption, respectively. Maximum adsorption ( q m ) of 27.25 mg/g and 416.7 mg/g were obtained for adsorption of SMZ and RB19, respectively on GO-IL. Thermodynamic studies revealed adsorption was exothermic and the data obtained supported the pseudo-second order kinetic model, and both Langmuir and Freundlich isotherm models. The adsorption mechanism was attributed to hydrophobic effects, hydrogen bonding, electrostatic and π - π interaction. Regeneration studies showed adsorbent reusability. This is the first report that shows the adsorption study of RB19 and SMZ on GO modified with a C14 long chain imidazolium IL. The hybrid adsorbent improved dispersion in aqueous medium, thus enhancing efficiency and cost effectiveness for the removal of RB19 and SMZ. This study helps to provide mechanistic insight into the adsorption process of RB19 and SMZ.

Organic solvents such as ethanol, find a wide range of applications in fuel, pharmaceutical industries, food industries, and paint formulations, among others. The removal of Ag(I), Co(II), and Mn(II) ions in ethanol by cation exchange resin, Dowex 50W-x8, was investigated. The adsorption characteristics of metal ions onto Dowex 50W-x8 resin were described by Langmuir isotherms. The maximum sorption exchange capacities at 298 K were obtained as 47.4 mg g−1, 52.6 mg g−1, and 58.5 mg g−1 for Ag(I), Co(II), and Mn(II), respectively. The data was also fitted to Temkin and Dubinin-Radushkevich adsorption isotherm models to evaluate other adsorption properties. The ion exchange of silver, cobalt, and manganese on cation exchange resin followed pseudo-second-order kinetics, and the intraparticle diffusion was rate-determining step. The thermodynamic parameters indicated that the sorption of metal ions onto Dowex 50W-x8 resin was spontaneous (negative ΔG°) and endothermic in nature (positive ΔH°) implying that the...

The occurrences of pharmaceuticals and personal care products as emerging organic contaminants (EOCs) have been reported in several countries of the world except from African countries. This study was therefore conducted to investigate the occurrence of nine antibiotics, five antipyretics, atenolol, bezafibrate, and caffeine in wastewater and surface water samples from the Umgeni River. The water samples were extracted with solid-phase extraction using hydrophilic-lipophilic balance (HLB) and C-18 cartridges for the acidic and neutral drugs, respectively. The quantification was carried out with high-performance liquid chromatography-diode array detector (HPLC-DAD) using the standard addition method. The method limits of detections were in the range of 0.14-0.97 μg/L while the recoveries were between 53.8 and 108.1 %. The wastewater had 100 % occurrence of the analytes studied, with caffeine having the highest concentration at 61 ± 5 μg/L and nalidixic acid being the most observed antibiotic at 31 ± 3 μg/L. The waste treatment process reduced the influent concentrations by 43.0-94.2 % before discharge except for atenolol removal that is lower. The concentrations of the analytes were lower in the surface water with most compounds having concentrations below 10 μg/L except acetaminophen and atenolol. The estuary mouth and Blue Lagoon had the highest concentrations of some of the compounds in surface water which depict downstream load. The factors governing the fate and mobility of these compounds in this environment are not fully understood yet and will require further studies.

A hollow fiber-liquid phase microextraction (HF-LPME) method for the simultaneous extraction and preconcentration of Ag, Al, As, Mn and Ti as ammonium pyrrolidine dithiocarbamate (APDC) complexes in [C 6 MIM][PF 6 ] ionic liquid are reported. Multivariate techniques such as 2 4 factorial and Box–Behnken designs were used for the optimization of experimental parameters. Under optimized conditions, the limits of detection and quantification ranged from 0.04 to 0.09 and 0.15–0.29 μg L − 1 , respectively. The preconcentration factors of 150, 291, 112, 405, 367 for Ag, Al, As, Mn and Ti, respectively, were achieved. The precision of the HF-LPME method estimated as the relative standard deviation (RSD) for five replicate determinations of metal ions at a concentration of 10 μg L − 1 was less than 5%. The HF-LPME method was verified by analysis of the target analytes in commercial diesel and gasoline samples. The accuracy of the proposed method was confirmed by performing standard addition method (spike recovery experiments, that is, spiking the samples with known amount of the standard). The recovery values (96–101%) indicated a satisfactory accuracy.

Chelex-100, Dowex 50W-x8 and Dowex MAC-3 exchange resins were investigated for separation and pre-concentration of trace amounts of Cd, Cr, Cu, Fe, Mn, Pb, Ti and Zn in alcohols with respect to retention and desorption characteristics. Dowex 50W-x8 was found to be the best sorbent with percentages recoveries95%. In addition, Chelex-100 appeared to be suitable for the pre-concentration of Cu, Fe and Zn, whereas Dowex MAC-3 was selective for Cu and Fe. Therefore, Dowex 50W-x8 was used for further investigations. The relative standard deviations4% (n=20), limits of detection and quantification were 0.1-1.2 μg L(-1) and 0.3-1.5 μg L(-1), respectively. The SPE method was validated against a certified reference material and the results were in agreement with certified values. The accuracy of the optimized method was verified by the recovery test in the spiked alcohol samples. The accuracy and spike recovery test for different metal ions were in the range 98-102% and 95-105%, respectively. The optimized method was applied to the separation and pre-concentration of metal ions in different commercial alcohol samples.