Precious Nokwethemba Mahlambi

Abacavir sulphate residues reported in South African water resources highlight the need for monitoring pharmaceutical contaminants to assess wastewater treatment efficiency and protect aquatic ecosystems. This study aimed to determine whether combining molecularly imprinted polymers (MIPs) with a carbon paste electrode (CPE) could improve the selectivity and sensitivity of abacavir detection while providing a cost-effective alternative to conventional methods. The optimized MIP-CPE sensor was applied to determine abacavir sulphate in real water matrices. The MIP was attained by bulk polymerization and coupled with CPE. The MIP had thermal stability of greater than 300 °C. Using differential pulse voltammetry (DPV), it was possible to quantify abacavir sulphate using a redox probe; a linear response in a range of 2 to 14 µM with a correlation coefficient (R²) of 0.991 was observed, with lower limits of detection (LOD) and quantification (LOQ) of 1.47 µM and 4.47 µM, respectively. Thus, the developed MIP-CPE sensor can be used to detect analyte residues present at trace levels. The developed sensor demonstrated satisfactory accuracy and precision in real water matrices, achieving recoveries of 82.2–101.2% with RSD values of 1.27–7.34% for spiked abacavir sulphate concentrations of 8 and 12 µM. The presence of abacavir sulphate was only detected in uMhlathuzana wastewater effluent samples, with a concentration of 7.19 µM (RSD 7.40%, n = 3). The MIP-CPE showed high selectivity for abacavir sulphate when tested alongside common interferents (lamivudine, ibuprofen, nevirapine, and trimethoprim). Abacavir sulphate gave the lowest peak current (DPV) of the group (489 µA), due to the ferricyanide peak falling when the target rebinds and blocks the probe. A lower current for abacavir therefore means more rebinding, which is evidence of selectivity. The MIP-CPE sensor demonstrated rapid rebinding and strong affinity for abacavir sulphate, even in complex matrices. This study offers wastewater treatment plants as a cost-effective, sensitive, and selective analytical method for routine monitoring of antiretroviral contaminants before effluent discharge into environmental waters.

Heavy metal pollution, mainly from industrial wastewater, is an ongoing worldwide concern that threatens water quality. The present study investigated the potential of Cannabis sativa L . buds, both raw and chemically modified with glycine and sodium bicarbonate, to decontaminate Lead (Pb ²⁺ ) and Copper (Cu ²⁺ ) ions from wastewater. Fourier transform Infrared spectroscopy results showed that the chemical modification process altered the surface functional groups, as evidenced by shifts in the functional group peak intensities of the modified bio-adsorbents compared to those of the unmodified bio-adsorbent before adsorption. After the adsorption process, a reduction in peak intensities was observed due to adsorption interactions with metal ions. Scanning electron microscopy revealed an irregular and multi-layered surface with interconnected pore network structures of all assessed bio-adsorbents. However, sodium bicarbonate modified cannabis appeared to be more porous than both bio-adsorbents. Energy-dispersive X-ray spectroscopy identified carbon and oxygen as the major elemental components of the bio-adsorbents. X-ray diffraction spectroscopy revealed that the sodium bicarbonate modified bio-adsorbent exhibited a more crystalline form, while thermogravimetric analysis showed that it was more stable than glycine and raw cannabis biomaterial. These findings indicate that bio-adsorbents exhibit an enhanced adsorption capacity, whilst sodium bicarbonate modified cannabis is expected to perform better than the other bio-adsorbents. A batch adsorption method was employed and assessed by varying solution pH, temperature, mass dosage, initial metal concentration, and contact time in a binary system. The optimal adsorption conditions were determined to be a solution pH of 7, reaction time of 10 min, mass dosage of 10 mg, an initial adsorbate concentration of 10 mg/L, and an adsorption temperature of 25 ºC. According to the analysis of variance results, the effects of temperature and adsorbate concentration on the adsorption of metal ions showed the highest (> 61%) and lowest (> 3%) percentage contributions. The adsorption rates of Cu ²⁺ and Pb ²⁺ ions fitted a non-linear pseudo-first-order model, and the sorption mechanism was best described by a multilayered surface (the Freundlich isotherm). The metal ion adsorption process was found to be exothermic, spontaneous, and feasible. Sodium bicarbonate modified cannabis showed a larger maximum adsorption capacity (q _max ) (31.222–56.875 mg/g) than glycine modified cannabis (28.983–53.888 mg/g) and raw cannabis (26.151–30.527 mg/g) for Cu ²⁺ and Pb ²⁺ ions, respectively. The percentage removal efficiency in real wastewater samples was 74–88% for the raw bio-adsorbent, 80–100% for glycine, and 96–100% for the sodium bicarbonate-modified bio-adsorbent for Cu ²⁺ and Pb ²⁺ ions, respectively. Though all bio-adsorbents showed good performance in removing both metal ions, sodium bicarbonate-modified cannabis was shown to be superior. This study showed that Cannabis sativa L. buds can be efficiently applied and regenerated at least three times as bio-adsorbents for the removal of metal ions from wastewater samples. Cannabis sativa L . buds offer an efficient, affordable, and eco-friendly alternative for water monitoring compared with conventional adsorbents. Additionally, the potential applicability of Cannabis sativa buds could be further assessed on a large industrial scale analysis.

Pharmaceuticals have been the focus of research into South Africa’s water resources for the past ten years and more. Five pharmaceutical residues were examined in this investigation in plant, sediment, and river water samples from Durban, SA. Fenoprofen, diclofenac, naproxen, gemfibrozil, and ibuprofen were the compounds of interest; they are some of the most widely used and often prescribed medications globally. Compound concentrations found in sediments and river water ranged from 0.2 to 12.0 ng g⁻¹ and 0.2 to 5.1 µg L⁻¹, respectively. Different plant parts (roots, stems, and leaves) had varying quantities of the target compounds in the Stevia rebaudiana species. The most prevalent drug in Stevia rebaudiana was ibuprofen, which was discovered in roots at the highest concentration of 7.2 ng g⁻¹. Although there was no apparent trend in the amounts identified in different areas of Stevia rebaudiana in this preliminary analysis, it is hypothesized that these pharmaceuticals penetrate into the aquatic plant roots from water and then move into the stem and leaves. The partitioning coefficients (L kg⁻¹) varied from one sampling location to another; fenoprofen, diclofenac, naproxen, gemfibrozil, and ibuprofen and diclofenac ranged from 0.1 to 4.0, 0.9 to 6.8, 0.8 to 3.7, 0.2 to 8.5, and 0.6 to 5.6, respectively. This suggests that environmental factors, including climate and the existence of additional pollutants from water, as well as variations in physicochemical properties, may have an impact on the fates of these pharmaceuticals. Overall, it was found that the target compounds were present in river water, sediments, and Stevia rebaudiana. This suggests that Stevia rebaudiana may reduce water pollution by absorbing pharmaceuticals through its roots.

Food and nutrition insecurities remain major challenges in rural communities, highlighting the need to identify affordable and nutrient-dense indigenous food resources. Therefore, this study evaluated the nutritional composition, antioxidant activity, and phytochemical characteristics of Momordica balsamina and Hypoxis hemerocallidea collected from KwaZulu-Natal, South Africa. In this study, proximate composition, mineral content, antioxidant activity, FT-IR spectroscopy, and LC-MS analyses were conducted using standard analytical procedures. Results showed that M. balsamina contained significantly (p < 0.05) higher crude protein, fibre, ash, potassium, calcium, magnesium, total phenolics, flavonoids, carotenoids, and DPPH radical scavenging activity than H. hemerocallidea. In contrast, H. hemerocallidea exhibited higher carbohydrate and food energy content, indicating its value as an energy-rich indigenous food source. Both species demonstrated strong antioxidant activity, with DPPH inhibition exceeding 80%, confirming the presence of bioactive phytochemicals indicating antioxidant potential. FT-IR analysis identified several functional groups associated with phenolic compounds, flavonoids, and terpenes, while LC-MS analysis confirmed the presence of hypoxoside in H. hemerocallidea and suggested that detected ions are consistent with reported M. balsamina compounds without claiming confirmation of novel phytochemicals in the absence of MS/MS fragmentation and structural validation. These findings highlight the nutritional and nutraceutical potential of both plant species and support their promotion as affordable indigenous food resources capable of contributing to food, nutrition, and health security in rural communities.

Molecularly imprinted polymers (MIPs) have emerged as robust and versatile recognition elements for electrochemical sensing due to their high chemical and mechanical stability, cost-effective fabrication, and excellent selectivity toward target analytes. In recent years, MIP-based electrochemical sensors have gained significant attention for the detection of pharmaceutical contaminants in wastewater, addressing growing environmental and public health concerns. This review provides a comprehensive overview of the fundamental principles of molecular imprinting Emphasis is placed on fabrication strategies and electrochemical detection techniques, including cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Furthermore, it discusses imprinting mechanisms for different classes of contaminants, matrix effects, and other challenges. By critically analyzing recent applications, this work highlights key factors influencing sensor performance, such as sensitivity, selectivity, and detection limits. Finally, we touch on future perspectives, focusing on the development of more reliable, scalable, and environmentally sustainable sensing platforms for real-world wastewater monitoring.

A novel magnetized Lippia javanica (Fe‐ L. javanica ) biosorbent was synthesized and applied to address the environmental and health risks associated with the release of Cu(II), Pb(II), and Zn(II) ions into aquatic systems. Characterization confirmed successful modification of L. javanica , with Fe‐O groups detected by EDX, spherical nanoparticles observed via SEM, and enhanced thermal stability shown by TGA. The shift in pHpzc from 5.96 to 6.3 further indicated improved metal adsorption capacity. Adsorption studies showed higher removal efficiencies for Fe‐ L. javanica (up to 97%) compared to unmodified biomass. Statistical analysis (F‐test and ANOVA) confirmed that key parameters significantly affected performance. Kinetics followed a pseudo‐second‐order model ( R ² > 0.99), while the Freundlich and Weber–Morris models suggested multilayer adsorption and a multi‐step sorption mechanism. Equilibrium studies revealed higher maximum adsorption capacities ( Q _max ) for Fe‐ L. javanica (Cu: 119.04 mg/g, Zn: 142.85 mg/g, Pb: 181.81 mg/g) compared to unmodified L. javanica . Both biosorbents demonstrated high removal efficiencies in real water samples (81.26%–98.22%) and were successfully regenerated and reused over five cycles with 83%–97% efficiency. The study highlights Fe‐ L. javanica as a cost‐effective, sustainable, and magnetically separable adsorbent for efficient heavy metal removal from contaminated water.

The growing presence of pharmaceutical residues in the environment has aroused worries about their possible buildup and accumulation in the food chain, particularly in edible plants. Conventional analytical methods frequently fail to selectively isolate and quantify trace amounts of these chemicals in complex plant matrices. This study introduces an optimized methodology for the analysis of pharmaceuticals in vegetables. The enhanced molecularly imprinted solid phase extraction (MISPE) approach investigates the extraction of selected pharmaceuticals, fenoprofen, naproxen, diclofenac, ibuprofen, and gemfibrozil in vegetables. The extracted compounds were identified both qualitatively and quantitatively using a high‐performance liquid phase chromatographic (HPLC) system coupled with a photodiode array detector. This method was effectively implemented on vegetable samples collected from Durban, South Africa (SA), including lettuce, carrot, cucumber, and green pepper. The recovery rates varied from 45% to 103%, with relative standard deviation (%RSD) ranging from 0.9% to 13%. Fenoprofen was the most prevalent compound, exhibiting high concentrations in pepper and cucumber, with maximum concentrations of 6.44 and 4.99 mg kg ⁻¹ , respectively. The health index (HI) values for the vegetables ranged from 0.27 to 1.25. The pepper sample (1.25) surpassed the HI threshold value of 1, reflecting the health indicator risk associated with the consumption of peppers available within the area. The health risk assessment (HRI) values spanned from 0.00012 to 0.83 for both adults and children, suggesting no health risk associated with the consumption of these vegetables.

South Africa's widespread use of antiretroviral drugs and antibiotics generates significant pharmaceutical waste, overwhelming treatment plants and contaminating water. Therefore, improved wastewater treatment solutions are urgently needed. In this study, Chlorella spp. was investigated as a sustainable bioremediation agent for removing sulfamethoxazole, efavirenz and nevirapine from water. Results exhibited that extended light exposure enhanced photosynthetic activity and biomass accumulation. Furthermore, high algal concentrations accelerated growth, but excessively high densities led to overcrowding and nutrient depletion, while lower densities reduced cell‐to‐cell interactions and growth rates. Removal efficiencies ranged from 10% to 60% for efavirenz, 5% to 51% for nevirapine and 10% to 50% for sulfamethoxazole under controlled conditions (pH ~ 7, 23°C, 20:4 h light–dark cycle, 150 rpm orbital shaking, 10‐day incubation and initial pharmaceutical concentrations ranging from 0.25 to 5 mg/L). These rates were due to interactions between the pharmaceuticals and polar functional groups on the Chlorella spp. cell surface, enhancing adsorption. FTIR and SEM analyses confirmed these interactions, contributing to pollutant removal. The findings of this study highlight Chlorella spp. as a promising, low‐cost solution for mitigating pharmaceutical pollution, with strong potential for integration into existing wastewater treatment systems and scaling up for large‐scale municipal applications.

Microextraction methods such as hollow fibre‐liquid phase microextraction (HF‐LPME), dispersive liquid–liquid microextraction (DLLME), single‐drop microextraction (SDME) and ultrasound‐assisted emulsification microextraction (USAEME) have become prominent for analysing pharmaceuticals in wastewater. HF‐LPME, particularly the three‐phase system, excels in extracting pollutants with high efficiency. SDME, especially the direct immersion (DI) variant, is effective for moderately polar and non‐polar compounds. DLLME uses an immiscible dispersion and extraction solvent to separate analytes, while USAEME enhances extraction using ultrasonic waves. Recent research trends focus on incorporating ionic liquids and deep eutectic solvents to improve extraction performance. These miniaturized techniques offer high selectivity, efficient sample clean‐up and significant enrichment factors, making them superior to traditional methods like liquid–liquid extraction. Future developments are expected to further refine these methods for even better performance in pharmaceutical analysis. Complex‐Green Analytical Procedure Index (GAPI) is also used in research to assess the environmentally friendliness of the methodological approaches.

The presence of pharmaceuticals in water bodies has been reported to be mainly due to their incomplete removal by the conventional wastewater treatment processes, resulting to their release into the aquatic environment where they thratens to human health and aquatic life. Therefore, it is important to remove these pollutants from the aquatic environment using affordable highly efficient materials. The goal of this study was to incorporate silver nanoparticles (AgNPs) into MIPs for selective removal of sulfamethoxazole, nevirapine, and ibuprofen in wastewater. The AgNPs were synthesized using starch (St) and macadamia (MCD) as both reducing and stabilizing agents. Thermogravimetric analysis showed high stability for the St/MCD‐nanoMIPs. The ANOVA analysis revealed that the parameters affecting adsorption of St/MCD‐nanoMIPs have a significant difference (p70 %) and effective in removing the selected pharmaceuticals from wastewater.