A review of the adsorption method for norfloxacin reduction from aqueous media

Bacterial nanocellulose-clay film as an eco-friendly sorbent for superior pollutants removal from aqueous solutions

The persistent water treatment and separation challenge necessitates innovative and sustainable advances to tackle conventional and emerging contaminants in the aquatic environment effectively. Therefore, a unique three-dimensional (3D) network composite film (BNC-KC) comprised of bacterial nanocellulose (BNC) incorporated nano-kaolinite clay particles (KC) was successfully synthesized via an in-situ approach. The microscopic characterization of BNC-KC revealed an effective integration of KC within the 3D matrix of BNC. The investigated mechanical properties of BNC-KC demonstrated a better performance compared to BNC. Thereafter, the sorption performance of BNC-KC films towards basic blue 9 dye (Bb9) and norfloxacin (NFX) antibiotic from water was investigated. The maximum sorption capacities of BNC-KC for Bb9 and NFX were 127.64 and 101.68 mg/g, respectively. Mechanistic studies showed that electrostatic interactions, multi-layered sorption, and 3D structure are pivotal in the NFX/Bb9 sorption process. The intricate architecture of BNC-KC effectively traps molecules within the interlayer spaces, significantly increasing sorption efficiency. The distinctive structural configuration of BNC-KC films effectively addressed the challenges of post-water treatment separation while concurrently mitigating waste generation. The environmental evaluation, engineering, and economic feasibility of BNC-KC are also discussed. The cost estimation assessment of BNC-KC revealed the potential to remove NFX and Bb9 from water at an economically viable cost.

Seasonal variation and human health risk assessment of potentially toxic elements in pharmaceutical effluents around Ilorin metropolis, Nigeria

Potentially toxic elements (PTEs) are widely released into the environment as a result of increased urban and industrial development in recent years. The bulk of PTEs are cancer-causing and harm human health by producing free radicals. As a result, it is crucial to monitor, evaluate, and limit the effects of the elements on human health. In this study, levels of PTEs (As, Cr, Cd, Ni, Co, and Pb) in pharmaceutical effluents discharged along the Asa River around the Ilorin metropolis and their seasonal variations were evaluated. Water samples were collected from eight different locations over a two-season period along the river and analyzed for PTEs using atomic absorption spectrophotometry and an inductively coupled plasma optical emission spectrometer. As, Cd, Pb, Cr, Ni, and Co had mean PTE values in the effluents (both seasons) of 0.0258, 0.0233, 0.00193, 0.0176, and 0.0164 mg/L, respectively, with As and Pb surpassing the WHO standard. Maximum temperature and pH were measured for the physicochemical parameters in the wet season, whereas electrical conductivity and total dissolved solids were seen in the dry season. The average values of the metals in the human risk assessment for carcinogenicity were As > Cd > Pb > Cr > Ni > Co, with As above the recommended threshold in several locations. However, all of the metal hazard indices were < 1, indicating that the waters were suitable for domestic purposes. Nonetheless, the relevant authorities should mandate that pharmaceutical effluents be treated before being released into bodies of water.

Norfloxacin adsorption by torrefied coco peat biochar as a novel adsorbent in a circular economy framework

The current study reported torrefied coco-peat biochar treated at 200 °C, as a novel adsorbent exhibiting phenomenal norfloxacin (NFX) adsorption efficiency. The CHNS analysis confirmed the carbon abundance in the biochar (36.45%), however, XRF analysis indicated a significant presence of K2O (27.73%) and chlorine (7.49%). The XRD and Raman spectral analysis confirmed the amorphous structure of the biochar. Multilayer topology was evident in the SEM micrograph of biochar contributing to its large effective surface area. Additionally, the mesoporous structure of the adsorbent was verified by BET. The adsorption mechanism was predicted to be non-ionic since the zeta potential of both adsorbent and adsorbate was found negative. The process parameters were optimized at 30 °C, pH 6.9, dosage 7 g/L, antibiotic load 494.25 mg/L, and time of 89 min for a maximum of 99.52% adsorption of NFX using Central Composite Design, Analysis of Variance, and Response Surface Methodology. The adsorption process was exothermic, and spontaneous obeying the pseudo-second-order kinetics, while the bulk process was confined to surface adsorption. Isotherm study of NFX adsorption revealed the process to be a favorable, monolayer, and homogeneous adsorption. The NFX molecules were desorbed with an efficiency of 89.19% using 80% ethanol and upon recrystallization, 87.76% of the initial NFX was recovered as crude crystal. Moreover, the NFX removal efficiency was consistent across various water systems, tap water (99.02%), seawater (99.56%), river water (98.92%), pond water (98.26%), and distilled water (99.17%). The techno-economic analysis identified bulk expense as the biochar preparation ($0.82/kg) and the process will be profitable having recovered NFX sold at $6/kg instead of the present retail price ($71/kg). Thus, the study successfully demonstrated a zero-waste, self-sustainable, and revenue-generating water treatment process implementing the circular economy framework.

Recent Advances in Porous Bio-Polymer Composites for the Remediation of Organic Pollutants

The increasing awareness of the importance of a clean and sustainable environment, coupled with the rapid growth of both population and technology, has instilled in people a strong inclination to address the issue of wastewater treatment. This global concern has prompted individuals to prioritize the proper management and purification of wastewater. Organic pollutants are very persistent and due to their destructive effects, it is necessary to remove them from wastewater. In the last decade, porous organic polymers (POPs) have garnered interest among researchers due to their effectiveness in removing various types of pollutants. Porous biopolymers seem to be suitable candidates among POPs. Sustainable consumption and environmental protection, as well as reducing the consumption of toxic chemicals, are the advantages of using biopolymers in the preparation of effective composites to remove pollutants. Composites containing porous biopolymers, like other POPs, can remove various pollutants through absorption, membrane filtration, or oxidative and photocatalytic effects. Although composites based on porous biopolymers shown relatively good performance in removing pollutants, their insufficient strength limits their performance. On the other hand, in comparison with other POPs, including covalent organic frameworks, they have weaker performance. Therefore, porous organic biopolymers are generally used in composites with other compounds. Therefore, it seems necessary to research the performance of these composites and investigate the reasons for using composite components. This review exhaustively investigates the recent progress in the use of composites containing porous biopolymers in the removal of organic pollutants in the form of adsorbents, membranes, catalysts, etc. Information regarding the mechanism, composite functionality, and the reasons for using each component in the construction of composites are discussed. The following provides a vision of future opportunities for the preparation of porous composites from biopolymers.

Surface-Functionalized Magnetic Silica-Malachite Tricomposite (Fe-M-Si tricomposite): A Promising Adsorbent for the Removal of Cypermethrin

This study assessed the efficacy of adsorption for eliminating the agricultural pesticide cypermethrin (CP) from wastewater using various adsorbents: silica, malachite, and magnetite. Magnetic nanocomposites (NCs) (with varying amounts of Fe3O4 0.1, 0.25, 0.5, 1.0, and 1.5 wt/wt %) were synthesized, including Fe3O4 nanoparticles (NPs), bicomposites, and tricomposites, calcined at 300 and 500 °C, and then tested for CP removal. The study was conducted in two phases, with the objective of initially assessing how effectively each individual NP performed and then evaluating how effectively the NCs performed when used for the adsorption of CP. Notably, the Fe3O4-malachite combination exhibited superior CP removal, with the 0.25-Fe-M NC achieving the highest adsorption at 635.4 mg/g. This success was attributed to the large surface area, magnetic properties of Fe3O4, and adsorption capabilities of malachite. The Brunauer-Emmett-Teller (BET) isotherm analysis indicated that the NCs had potential applications in adsorption and separation processes. The scanning electron microscopy and transmission electron microscopy revealed the spherical, irregular shaped morphology of the synthesized NPs and NCs. However, the X-ray diffraction (XRD) pattern of surface functionalized materials such as surface functionalized malachite [Cu2CO3(OH)2] with Fe3O4 and SiO2 may be complicated by the specific functionalization method used and the relative amounts and crystallographic orientations of each component. Therefore, careful interpretation and analysis of the XRD pattern, along with other techniques, are necessary for accurate identification and characterization of the functionalized material. The originality of this study lies in its comprehensive investigation of several adsorbents and NCs for CP removal at neutral pH. The innovation stems from the synergistic action of Fe3O4 and malachite, which results in improved CP removal due to their combined surface properties and magnetic characteristics. The application of magnetic NCs in adsorption and separation, as validated by BET isotherm analysis, highlights the potential breakthrough in addressing pesticide contamination.

Environmental remediation of the norfloxacin in water by adsorption: Advances, current status and prospects

Antibiotics are considered as the new generation water pollutants as these disturb endocrine systems if water contaminated with antibiotics is consumed. Among many antibiotics norfloxacin is present in various natural water bodies globally. This antibiotic is considered an emerging pollutant due to its low degradation in aquatic animals. Besides, it has many side effects on human vital organs. Therefore, the present article discusses the recent advances in the removal of norfloxacin by adsorption. This article describes the presence of norfloxacin in natural water, consumption, toxicity, various adsorbents for norfloxacin removal, optimization factors for norfloxacin removal, kinetics, thermodynamics, modeling, adsorption mechanism and regeneration of the adsorbents. Adsorption takes place in a monolayer following the Langmuir model. The Pseudo-second order model represents the kinetic data. The adsorption capacity ranged from 0.924 to 1282 mg g-1. In this sense, the parameters such as the NFX concentration added to the adsorbent textural properties exerted a great influence. Besides, the fixed bed-based removal at a large scale is also included. In addition to this, the simulation studies were also discussed to describe the adsorption mechanism. Finally, the research challenges and future perspectives have also been highlighted. This article will be highly useful for academicians, researchers, industry persons, and government authorities for designing future advanced experiments.

Synergistic mechanisms for the superior sorptive removal of aquatic pollutants via functionalized biochar-clay composite

This study investigated the successful synthesis of functionalized algal biochar-clay composite (FBKC). Subsequently, the sorption performance of FBKC towards norfloxacin (NFX) antibiotic and crystal violet dye (CVD) from water was extensively assessed in both batch and continuous flow systems. A series of characterization techniques were carried out for FBKC and the utilized precursors, indicating that the surface area of FBKC was increased thirty-fold with a well-developed pore structure compared to the original precursors. FBKC demonstrated a maximum sorption capacity of 192.80 and 281.24 mg/g for NFX and CVD, respectively. The suited fitting of the experimental data to Freundlich and Clark models suggested multi-layer sorption of NFX/CVD molecules. The mechanistic studies of NFX/CVD sorption onto FBKC unveiled multiple mechanisms, including π-π interaction, hydrogen bonding, electrostatic attraction, and surface/pore filling effect. The estimated cost of 5.72 €/kg and superior sorption capacity makes FBKC an efficient low-cost sorbent for emergent water pollutants.

A recent overview of surfactant-drug interactions and their importance

This review focuses on the self-aggregation properties of different drugs, as well as on their interaction with anionic, cationic, and gemini surfactants. The interaction of drugs with surfactants has been reviewed concerning conductivity, surface tension, viscosity, density, and UV-Vis spectrophotometric measurements, and their relation with critical micelle concentration (CMC), cloud point, and binding constant. The conductivity measurement technique is used for the micellization of ionic surfactants. Cloud point studies can be used for the non-ionic, and also for certain ionic surfactants. Usually, surface tension studies are mostly employed for non-ionic surfactants. The degree of dissociation that is determined is used to evaluate thermodynamic parameters of micellization at various temperatures. The effect of external parameters like temperature, salt, solvent, pH, etc., is discussed for thermodynamics parameters using recent experimental works on drug-surfactant interactions. Consequences of drug-surfactant interaction, condition of drugs during interaction with surfactants, and applications of drug-surfactant interaction are being generalized which reflects current and future potential uses of drug-surfactant interactions.