Ag and CuO nanoparticles decorated on graphene oxide/activated carbon as a novel adsorbent for the removal of cephalexin from water

Adsorption of chloroquine, propranolol, and metformin in aqueous solutions using magnetic graphene oxide nanocomposite

The work proposes the application of a nanocomposite formed by graphene oxide and magnetite to remove chloroquine, propranolol, and metformin from water. Tests related to adsorption kinetics, equilibrium isotherms and adsorbent reuse were studied, and optimization parameters related to the initial pH of the solution and the adsorbent dosage were defined. For all pharmaceuticals, adsorption tests indicated that removal efficiency was independent of initial pH at adsorbent dosages of 0.4 g L-1 for chloroquine, 1.2 g L-1 for propranolol, and 1.6 g L-1 for metformin. Adsorption equilibrium was reached within the first few minutes, and the pseudo-second-order model represented the experimental data well. While the equilibrium data fit the Sips isotherm model at 298 K, the predicted maximum adsorption capacities for chloroquine, propranolol, and metformin were 44.01, 16.82, and 12.23 mg g-1, respectively. The magnetic nanocomposite can be reused for three consecutive cycles of adsorption-desorption for all pharmaceuticals, being a promising alternative for the removal of different classes of pharmaceuticals in water.

Recent perspective of antibiotics remediation: A review of the principles, mechanisms, and chemistry controlling remediation from aqueous media

Antibiotic pollution is an ever-growing concern that affects the growth of plants and the well-being of animals and humans. Research on antibiotics remediation from aqueous media has grown over the years and previous reviews have highlighted recent advances in antibiotics remediation technologies, perspectives on antibiotics ecotoxicity, and the development of antibiotic-resistant genes. Nevertheless, the relationship between antibiotics solution chemistry, remediation technology, and the interactions between antibiotics and adsorbents at the molecular level is still elusive. Thus, this review summarizes recent literature on antibiotics remediation from aqueous media and the adsorption perspective. The review discusses the principles, mechanisms, and solution chemistry of antibiotics and how they affect remediation and the type of adsorbents used for antibiotic adsorption processes. The literature analysis revealed that: (i) Although antibiotics extraction and detection techniques have evolved from single-substrate-oriented to multi-substrates-oriented detection technologies, antibiotics pollution remains a great danger to the environment due to its trace level; (ii) Some of the most effective antibiotic remediation technologies are still at the laboratory scale. Thus, upscaling these technologies to field level will require funding, which brings in more constraints and doubts patterning to whether the technology will achieve the same performance as in the laboratory; and (iii) Adsorption technologies remain the most affordable for antibiotic remediation. However, the recent trends show more focus on developing high-end adsorbents which are expensive and sometimes less efficient compared to existing adsorbents. Thus, more research needs to focus on developing cheaper and less complex adsorbents from readily available raw materials. This review will be beneficial to stakeholders, researchers, and public health professionals for the efficient management of antibiotics for a refined decision.

Advances in solid-phase extraction techniques: Role of nanosorbents for the enrichment of antibiotics for analytical quantification

Antibiotics are life-saving medications for treating bacterial infections; however it has been discovered that resistance developed by bacteria against these incredible agents is the primary contributing factor to rising global mortality rates. The fundamental cause of the emergence of antibiotic resistance in bacteria is the presence of antibiotic residues in various environmental matrices. Although antibiotics are present in diluted form in environmental matrices like water, consistent exposure of bacteria to these minute levels is enough for the resistance to develop. So, identifying these tiny concentrations of numerous antibiotics in various and complicated matrices will be a crucial step in controlling their disposal in those matrices. Solid phase extraction, a popular and customizable extraction technology, was developed according to the aspirations of the researchers. It is a unique alternative technique that could be implemented either alone or in combination with other approaches at different stages because of the multitude of sorbent varieties and techniques. Initially, sorbents are utilized for extraction in their natural state. The basic sorbent has been modified over time with nanoparticles and multilayer sorbents, which have indeed helped to accomplish the desired extraction efficiencies. Among the current traditional extraction techniques such as liquid-liquid extraction, protein precipitation, and salting out techniques, solid-phase extractions (SPE) with nanosorbents are most productive because, they can be automated, selective, and can be integrated with other extraction techniques. This review aims to provide a broad overview of advancements and developments in sorbents with a specific emphasis on the applications of SPE techniques used for antibiotic detection and quantification in various matrices in the last two decades.

Investigation of two new low-cost adsorbents functionalized with magnetic nanoparticles for the efficient removal of triclosan and a synthetic mixture

Triclosan (TCS) is widely used in the production of antibacterial products, being often found in wastewater. Therefore, this study developed new materials via soybean hulls (SBH_F) and açaí seeds (AÇS_F) functionalization with iron oxide nanoparticles to be applied in the TCS adsorption. The characterization confirmed the functionalization of the materials. The adsorption results indicated that the equilibrium of the process occurred after 480 and 960 min for SBH_F and AÇS_F, respectively. The maximum adsorptive capacity values were 158.35 and 155.09 mg g^-1 for SBH_F and AÇS_F, respectively, at 318 K. The kinetic and isothermal data better fitted to the pseudo-second-order and Langmuir models. Thermodynamics indicated that the processes had an endothermic, spontaneous, and reversible character. The main adsorption mechanisms were H-bond and π-interactions. The pH and ionic strength studies indicated that the adsorption efficiency has not been reduced pronouncedly. The biosorbents reuse was effective for five cycles. In the synthetic mixture, the removal rate was satisfactory (92.53% and 57.02%, respectively for SBH_F and AÇS_F)_. These results demonstrate the biosorbents high potential for large-scale application.

Insights on synthesis and applications of graphene-based materials in wastewater treatment: A review

Graphene has excellent unique thermal, chemical, optical, and mechanical properties such as high thermal conductivity, high chemical stability, optical transmittance, high current density, higher surface area, etc. Due to their outstanding properties, the attention towards graphene-based materials and their derivatives in wastewater treatment has been increased in recent times. Different graphene-based materials such as graphene oxides, graphene quantum dots, graphene nanoplatelets, graphene nanoribbons and other graphene-based nanocomposites are synthesized through chemical vapor deposition, mechanical and electrochemical exfoliation of graphite. In this review, the specifics about the graphenes and their derivatives, the synthesis strategy of graphene-based materials are described. This review critically explained the applications of graphene-based materials in wastewater treatment. Graphene-based materials were utilized as adsorbents, electrodes, and photocatalysts for the efficient removal of toxic pollutants such as heavy metals, dyes, pharmaceutics, antibiotics, phenols, polycyclic aromatic hydrocarbons have been highlighted and discussed. Herein, the potential scope of graphene-based material in the field of wastewater treatment is critically reviewed. In addition, a brief perspective on future research directions and difficulties in the synthesis of graphene-based material are summarized.

Oxygen Scavenging Hybrid Nanostructure: Localization of Different Iron Nanoparticles on Montmorillonite Clays Host

According to the great potential of zero-valent iron nanoparticle applications in the environmental, medical, chemical, packaging and many other industries, there is still a need to tailor their production methods. This study reports the production of a hybrid nanostructure based on iron nanoparticles (INPs) produced in/on montmorillonite (MMT) nanoclays as an oxygen scavenger and barrier additive in polymeric packaging materials of oxygen-sensitive products. INPs and MMT were demonstrated to have effective mutual interactions in which the MMT host played a chemophysical trapping role for iron particles, causing smaller particles around 10 nm with 6.2 g/m² higher specific surface area by limiting particle growth and agglomeration. In return, the embedding of primary iron cations in/on clays and growth of these particles during the reduction reaction pushed the clay layers out and helped further clay intercalation-exfoliation. Effective study of solvent and primary cation (Fe²⁺/Fe³⁺) types showed different preferences in interacting with natural and alkylammonium-modified MMT, resulting in the different site selection. Fe²⁺ cations preferred to migrate to the interlayer space, whereas Fe³⁺ cations tended to bond to the clay surface. The obtained results in this study suggest tailoring the ultimate oxygen scavenging capacity, shelf life, and migration properties of a hybrid nanoparticle according to the application requirements.

Application of activated carbon functionalized with graphene oxide for efficient removal of COVID-19 treatment-related pharmaceuticals from water

Currently, the COVID-19 pandemic has been increasing the consumption of some drugs, such as chloroquine (CQN) and dipyrone (DIP), which are continuously discharged into water resources through domestic sewage treatment systems. The presence of these drugs in water bodies is worrisome due to their high toxicity, which makes crucial their monitoring and removal, especially by means of advanced technologies. Given this scenario, a new adsorbent material was synthesized through the combination of babassu coconut activated carbon and graphene oxide (GAC-GO). This study was evaluated in batch adsorption processes, aiming at the treatment of water contaminated with CQN and DIP. Characterization analyzes using physicochemical and spectroscopic techniques indicated that the GAC-GO functionalization was successfully performed. The equilibrium time of the adsorption process was 18 and 12 h for CQN and DIP, respectively. Kinetic and isothermal data better fitted to pseudo-second-order and Langmuir models for both drugs. Thermodynamic parameters showed that the process is endothermic and the maximum adsorption capacities of CQN and DIP were 37.65 and 62.43 mg g-1, respectively, both at 318 K. The study of the effect of ionic strength, which simulates a real effluent, demonstrated that the synthesized adsorbent has potential application for the treatment of effluents. Furthermore, satisfactory removal rates were verified for the removal of other contaminants in both simple solutions and synthetic mixtures, evidencing the versatile profile of the adsorbent.