For decades, there has been increasing interest in pharmaceuticals’ prevalence in water bodies. This represents a major challenge in providing clean water, free from pharmaceutical contaminants, in different parts of the world. The misuse and overuse of pharmaceuticals, their elevated concentrations in surface waters, and their negative impacts on humans, aquatic organisms, and ecosystems cannot be ignored. Significant efforts have been made toward the discovery of efficient water treatment techniques. Various technologies have been researched and applied, including co-precipitation, membrane separation, ion-exchange, oxidation, adsorption, and biochemical processes. Amidst these technologies, adsorption is considered a promising due to its unique advantages. This review discusses the pharmaceuticals that have been detected in surface waters in concentrations ranging from ng/L to μg/L. It also offers insights into the diverse applications of low-cost adsorbents to deal with pharmaceutical water pollutants and various parameters influencing the adsorption process. This article will assist in promoting the utilization of sustainable, low-cost adsorbents with high adsorption efficiencies in the water treatment process, and it will aid environmentalists in devising strategies for anticipated challenges and provide policymakers with valuable guidance.

The removal of excessive amounts of antibiotics from water systems is of great benefit due to their adverse effects on the ecosystems, living organisms and the persistent increase in antibiotic resistance cases. This study was focused on the adsorption of vancomycin from a simulated aqueous medium using seaweed, a sustainable and low-cost adsorbent. Also, the work focuses on assessing the influence of surface modification on adsorption behaviour and determining if chemical treatment provides improvements over untreated seaweed. In particular, chemically modified seaweed and raw (non-modified) seaweed were assessed as adsorbents suitable for removing traces of vancomycin from water, as gauged from the results of High-Performance Liquid Chromatography (HPLC). In addition, Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FT-IR) and the pH point of zero charge (pH_pzc) were used to measure the surface characteristics of these adsorbents. The degree of antibiotic adsorption was evaluated as a function of different factors, including the pH, adsorbent dosage, contact time, ionic strength and initial concentration of vancomycin. Thermodynamic parameters, such as the enthalpy change (∆H°), the entropy change (∆S°) and the free-energy change (∆G°), were calculated. The FTIR analysis indicates that functional groups, such as carbonyl and hydroxyl groups, were involved in the adsorption process, and their modification influenced adsorption behaviour. It was observed that the adsorption of vancomycin by the modified seaweed was slightly lower (±94%) compared to the level achieved for the raw seaweed (±97%). These figures were obtained with an initial concentration of vancomycin of 25 mg/L, a pH of the aqueous solution of 7.0, an adsorbent dose of 0.2 g and a contact time of 120 min. The results showed that untreated seaweed exhibited slightly higher adsorption efficiency than the treated seaweed, suggesting that chemical modification might not have enhanced adsorption performance. The thermodynamic parameters suggested that the adsorption process was exothermic and that adsorption was favourable for the untreated seaweed and less favourable for the treated seaweed. Regeneration studies showed a decrease in adsorption efficiency over repeated cycles. Although the adsorption capacity is lower than that of advanced nanomaterials, the use of seaweed offers an advantage in terms of low cost, availability and environmental sustainability. The comparable efficiency of the modified and untreated seaweed adsorbent suggests that seaweed adsorbents can be used as viable bio-adsorbents for the decontamination of water.