Encapsulation of starch hydrogel and doping nanomagnetite onto metal-organic frameworks for efficient removal of fluvastatin antibiotic from water

Functionalizing natural polymers to develop green adsorbents for wastewater treatment applications

The present study provides an overview of scientific developments made in the last decade in the field of green adsorbents focusing on the modifications in natural polymers and their applications such as, wastewater treatment, and ion exchange. For this purpose, an introduction to the various methods of modifying natural polymers is first given, and then the properties, application, and future priorities of green adsorbents are also discussed. Methods of modification of natural polymers under homogeneous and heterogeneous conditions using modifiers with different properties are also described. Various methods for modifying natural polymers and the use of the obtained green adsorbents are reviewed. A comparison of the sorption properties of green adsorbents based on natural polymers and other adsorbents used in industry has also been carried out. With the participation of green adsorbents based on natural polymers, the properties of treated wastewaters having toxic metal ions, organic dyes, petroleum products, and other harmful compounds was analyzed. Future perspectives on green adsorbents based on natural polymers are as also highlighted.

Metal-organic gels: recent advances in their classification, characterization, and application in the pharmaceutical field

Metal-organic gels (MOGs) are a type of functional soft substance with a three-dimensional (3D) network structure and solid-like rheological behavior, which are constructed by metal ions and bridging ligands formed under the driving force of coordination interactions or other non-covalent interactions. As the homologous substances of metal-organic frameworks (MOFs) and gels, they exhibit the potential advantages of high porosity, flexible structure, and adjustable mechanical properties, causing them to attract extensive research interest in the pharmaceutical field. For instance, MOGs are often used as excellent vehicles for intelligent drug delivery and programmable drug release to improve the clinical curative effect with reduced side effects. Also, MOGs are often applied as advanced biomedical materials for the repair and treatment of pathological tissue and sensitive detection of drugs or other molecules. However, despite the vigorous research on MOGs in recent years, there is no systematic summary of their applications in the pharmaceutical field to date. The present review systematically summarize the recent research progress on MOGs in the pharmaceutical field, including drug delivery systems, drug detection, pharmaceutical materials, and disease therapies. In addition, the formation principles and classification of MOGs are complemented and refined, and the techniques for the characterization of the structures/properties of MOGs are overviewed in this review.

Biogenic adsorbents for removal of drugs and dyes: A comprehensive review on properties, modification and applications

This comprehensive review explores the potential and versatility of biogenic materials as sustainable and environmentally benign alternatives to conventional adsorbents for the removal of drugs and dyes. Biogenic adsorbents derived from plants, animals, microorganisms, algae and biopolymers have bioactive compounds that interact with functional groups of pollutants, resulting in their binding with the sorbent. These materials can be modified mechanically, thermally and chemically to enhance their adsorption properties. Biogenic hybrid composites, which integrate the characteristics of more than one material, have also been fabricated. Additionally, microorganisms and algae are analyzed for their ability to uptake pollutants. Various influential factors that contribute to the adsorption process are also discussed. The challenge, limitations and future prospects for research are reviewed and bridging gap between large scale application and laboratory scale. This comprehensive review, involves a combination of various biogenic adsorbents, going beyond the existing literature where typically only specific adsorbents are reported. The review also covers the isotherms, kinetics, and desorption studies of biogenic adsorbents, providing an improved framework for their effective use in removing pharmaceuticals and dyes from wastewater.

Starch-Based Polymer Materials as Advanced Adsorbents for Sustainable Water Treatment: Current Status, Challenges, and Future Perspectives

Over the past three decades, chemical and biological water contamination has become a major concern, particularly in the industrialized world. Heavy metals, aromatic compounds, and dyes are among the harmful substances that contribute to water pollution, which jeopardies the human health. For this reason, it is of the utmost importance to locate methods for the cleanup of wastewater that are not genuinely effective. Owing to its non-toxicity, biodegradability, and biocompatibility, starch is a naturally occurring polysaccharide that scientists are looking into as a possible environmentally friendly material for sustainable water remediation. Starch could exhibit significant adsorption capabilities towards pollutants with the substitution of amide, amino, carboxyl, and other functional groups for hydroxyl groups. Starch derivatives may effectively remove contaminants such as oil, organic solvents, pesticides, heavy metals, dyes, and pharmaceutical pollutants by employing adsorption techniques at a rate greater than 90%. The maximal adsorption capacities of starch-based adsorbents for oil and organic solvents, pesticides, heavy metal ions, dyes, and pharmaceuticals are 13,000, 66, 2000, 25,000, and 782 mg/g, respectively. Although starch-based adsorbents have demonstrated a promising future for environmental wastewater treatment, additional research is required to optimize the technique before the starch-based adsorbent can be used in large-scale in situ wastewater treatment.

Recent advances in adsorption of environmental pollutants using metal-organic frameworks-based hydrogels

Water pollution is increasing significantly owing to industrialization and population growth that lead to serious environmental and health issues. Therefore, the design and development of more effective wastewater treatment approaches are necessary due to a significant upsurge in demand for freshwater. More recently, metal-organic frameworks (MOFs) have attracted attention in environmental science owing to their tunable porosity, unique structure, flexibility, and various composition. Despite these attractive advantages, some drawbacks, including intrinsic fragility, unsatisfied processability, dust formation, and poor reusability, have greatly limited their applications. Therefore, MOFs are often designed as supported-based MOFs (e.g., MOFs-coated composites) or 3D structured composites, such as MOFs-based hydrogels. MOFs-based hydrogels are excellent candidates in the sorption process because of their appropriate adsorption capacity, porous structure, good mechanical properties, durability as well as biodegradable features. In this review, the removal of different pollutants (e.g., synthetic dyes, phosphates, heavy metals, antibiotics, and some organic compounds) from aqueous media has been studied by the adsorption process using MOFs-based hydrogels. The important advancements in the fabrication of MOFs-based hydrogels and their capacities in the adsorption of pollutants under experimental conditions have been discussed. Finally, problems and future perspectives on the adsorption process using MOFs-based hydrogels have been investigated.

Exploring eco-friendly approaches for mitigating pharmaceutical and personal care products in aquatic ecosystems: A sustainability assessment

Global water scarcity is exacerbated by climate change, population growth, and water pollution. Over half of the world's population will be affected by water shortages for at least a month annually by 2050 due toa lack of clean water sources. Even though recycling wastewater helps meet the growing demand, new pollutants, including pharmaceuticals and personal care products (PPCPs), pose a health threat since conventional methods cannot remove them and their environmental monitoring regulations are yet in place. Therefore, the current review aims to investigate and propose eco-friendly technologies for removing PPCPs from wastewater and their implementation strategies for ecosystem safety. Findings indicated the absence of a single wastewater treatment technology that can remove all PPCPs in a single operation. Instead, biotechnological methods are one of the alternatives that can remove PPCPs from aquatic environments. In this context, community involvement and knowledge transfer are identified keys to clean water resources' long-term sustainability.

A study on the adsorption property and mechanism of β-cyclodextrin/polyvinyl alcohol/polyacrylic acid hydrogel for ciprofloxacin

Polyvinyl alcohol (PVA), acrylic acid (AA), and β-cyclodextrin (β-CD) were used as monomers, and ammonium persulfate was used as an initiator. Orthogonal tests were optimized the experimental condition, and aqueous polymerization was used to prepare poly-β-cyclodextrin/polyvinyl alcohol/polyacrylic acid (β-CD/PVA/PAA) hydrogel. The samples were characterized by FT-IR (Fourier transform infrared), SEM (Scanning electron microscopy), and XRD (X-ray diffraction). β-CD/PVA/PAA hydrogel was analyzed, which influenced external environmental factors on the β-CD/PVA/PAA hydrogel adsorption performance, and the kinetic behavior of β-CD/PVA/PAA hydrogel on ciprofloxacin (CIP) adsorption was explored. The results concluded that the prepared β-CD/PVA/PAA hydrogel has a well-defined three-dimensional network structure. The decrease in the pH of the CIP solution and the adsorption temperature reduces the adsorption reaction of β-CD/PVA/PAA hydrogel on CIP. The kinetics of CIP adsorption by β-CD/PVA/PAA hydrogel confirmed the pseudo-second-order kinetic model (R 2 > 0.997), the maximum equilibrium adsorption amounts is 372.12 mg/g, the removal rate reaches 74.42%. The adsorption process was mainly chemisorption, the adsorption isotherm fits the Freundlich adsorption isotherm model (R 2 > 0.946), and the adsorption process was heterogeneous with multi-molecular layer adsorption. The adsorption process inclined more toward the adsorption of inhomogeneous multi-molecular layers. The β-CD/PVA/PAA hydrogel retained 80% adsorption properties after three adsorption-desorption under optimal conditions.

Recent advances in starch-based magnetic adsorbents for the removal of contaminants from wastewater: A review

Considerable concern exists regarding water contamination by various pollutants, such as conventional pollutants (e.g., heavy metals and organics) and emerging micropollutants (e.g., consumer care products and interfering endocrine-related compounds). Currently, academics are continuously exploring sustainability-related materials and technologies to remove contaminants from wastewater. Magnetic starch-based adsorbents (MSAs) can combine the advantages of starch and magnetic nanoparticles, which exhibit unique critical features such as availability, cost-effectiveness, size, shape, crystallinity, magnetic properties, stability, adsorption properties, and excellent surface properties. However, limited reviews on MSAs' preparations, characterizations, applications, and adsorption mechanisms could be available nowadays. Hence, this review not only focuses on their activation and preparation methods, including physical (e.g., mechanical activation treatment, microwave radiation treatment, sonication, and extrusion), chemical (e.g., grafting, cross-linking, oxidation and esterification), and enzymatic modifications to enhance their adsorption properties, but also offers an all-round state-of-the-art analysis of the full range of its characterization methods, the adsorption of various contaminants, and the underlying adsorption mechanisms. Eventually, this review focuses on the recycling and reclamation performance and highlights the main gaps in the areas where further studies are warranted. We hope that this review will spark an interdisciplinary discussion and bring about a revolution in the applications of MSAs.

Development of hybrid green nanocomposite polymeric beads doped with nano sulfated zirconia for effective removal of Cefotaxime antibiotic from aqueous solution

Adsorption efficiency of Cefotaxime by novel nanocomposites beads composed of iota carrageenan (IC), sulfonated poly vinyl alcohol (SPVA) and nano sulfated zirconia (SZrO₂) was evaluated in this study. SZrO₂ was synthesized from solvent-free and easy calcination technique then embedded with 1–2.5 wt.% into the polymeric matrix. A batch adsorption experiment was carried out to investigate the effects of dosage, pH, beginning concentration, and time on Cefotaxime antibiotic adsorption. The ideal conditions to achieve complete removal are 88.97 mg L⁻¹ initial cefotaxime concentration at time 3.58 h with 11.68 mg of beads composite with 2.5 wt.% of SZrO₂. The pseudo second order kinetics model better illustrated the adsorption of cefotaxime on nanocomposite beads, and the maximum adsorption capacity are 659 mg g⁻¹ for the composite with 2.5 wt.% of SZrO₂. The mechanism of adsorption process depend mainly on the interactions between the different functional groups of SPVA, IC and SZrO₂. The nanocomposites beads also exhibit excellent reproducibility after ten adsorption cycles. This type of nanocomposites beads can be easily separated from water without leaving any residue, verifying this novel nanocomposite beads has strong potential in water treatment for the antibiotic contaminant removal.

The pioneering role of metal-organic framework-5 in ever-growing contemporary applications - a review

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal–organic frameworks (MOFs), with unique physical, chemical and mechanical properties. MOF-5 based composites possess ample applications in modern chemistry. Huge surface area, suitable pore dimensions and scope of tunability make MOF-5 noteworthy in advanced materials. The extensive features of MOF-5 provided an opportunity for researchers to explore atomic/molecular scale materials. Various MOF-5 based composites have been designed with revamped properties appropriate to the application by altering and fabricating MOF-5 in situ or using a post-synthetic approach. Surface modification via the dispersion and impregnation of active substances into the pores of MOF-5 enhances its applicability. The boundless topologies and morphologies of MOF-5 combined with other chemical entities has provided opportunities in various fields, including catalysis, gas storage and sensors. The present review illuminates the leading role of MOF-5 and its composites in contemporary applications based on the current literature in heterogeneous catalysis, H₂ and CO₂ storage and sensors.

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal–organic frameworks (MOFs), with unique physical, chemical and mechanical properties.

Critical review on adsorptive removal of antibiotics: Present situation, challenges and future perspective

This review gives a proper dedicated understanding of the contamination level, sources, and biological dangers related with different classes of antibiotics in consumable water. The literature on the adsorption of antibiotics is relatively uncommon and developments are still under progression, especially for adsorbents other than activated carbon. Also, adsorption technique has already been applied vastly for water treatment. Notwithstanding significant progressions, designed natural wastewater treatment frameworks are just bearably effective (48-77%) in the expulsion of antibiotics. Hence, the compilation of available literature especially for antibiotic adsorption was much needed. Moreover, the conventional adsorbents have some limitations of their own. In this study, the main focus was laid on unconventional adsorbents such as Biochar, Biopolymers, Carbon Nanotubes, Clays, Metal-Organic Frameworks, Microalgae and some miscellaneous adsorbents. The mechanism of adsorption by the unconventional adsorbents includes electrostatic interactions, π-π bonding, weak Van der Waal forces, H-bonding and surface complexation, which was similar to that of conventional adsorbents and hence these unconventional adsorbents can easily replace the costlier conventional adsorbents with even better adsorption efficiency. This paper also briefly discussed the thermodynamics, adsorption equilibrium; isotherm and kinetics of adsorption. This review paper seizes the critical advances of adsorption phenomenon at various interfaces and lays the foundation for current scenario associated with further progress. Besides, this study would help in understanding the antibiotic adsorption, cost estimation and future goals that will attract the young the researchers of this field.

The Effectiveness of MOFs for the Removal of Pharmaceuticals from Aquatic Environments: A Review Focused on Antibiotics Removal

There is an increasing level of various pollutants and their persistence in aquatic environments. The improper use of antibiotics and their inefficient metabolism in organisms result in their release into aquatic environments. Antibiotic abuse has led to hazardous effects on human health. Thereby, efficient removal of pharmaceuticals, particularly antibiotics, from wastewater and contaminated water bodies is greatly interested in international research communities. Metal-organic framework (MOF) materials, as a hybrid group of material containing metallic center and organic linkers, offer a porous structure that is highly efficient for removing different pollutants from contaminated water and wastewater streams. This article aims to review the recent advancement in using MOF-based adsorbents and catalysts for the removal of pharmaceuticals, especially antibiotics, from polluted water. Applying MOFs-based structures for removing antibiotics using photocatalytic removal and adsorptive removal techniques will be discussed and evaluated in this review paper. Various MOF-based materials such as functionalized MOFs, MOF-based composites, magnetic MOF-based composites, MOFs templated-metal oxide catalysts for removing pharmaceuticals, personal care products, and antibiotics from contaminated aqueous media are discussed. Furthermore, effective operational parameters on the adsorption, adsorption mechanisms, adsorption isotherms, and thermodynamic parameters are explained and discussed. Finally, in the concluding remarks, the challenges and future outlooks of using MOFs-based adsorbents and catalysts for removing antibiotics are summarized.

Construction of hydrogels based on the homogeneous carboxymethylated chitin from Hericium erinaceus residue: Role of carboxymethylation degree

Carboxymethyl chitin hydrogels with different degree of substitution (DS) were prepared by the homogeneous carboxymethylation of chitin extracted from Hericium erinaceus residue. The effect of DS on gel structure and property were studied. Results showed that the DS of carboxymethyl chitin hydrogels can be increased by increasing the amount of sodium chloroacetate. The equilibrium swelling degree and pH swelling sensitivity of the hydrogels were enhanced as the increase of DS. Zeta potential, low-field nuclear magnetic resonance, contact angle and molecular dynamics simulation results suggested that the introduction of carboxymethyl functional group enhanced the negative charge, water mobility, surface hydrophilicity and the ability to form hydrogen bonds with water of the hydrogels, resulting in an increased swelling degree of the hydrogels. Moreover, the prepared hydrogels showed different adsorption capability to various dyes, and the adsorption performance of the prepared hydrogels for cationic dyes could be enhanced as the increase of DS.

A review of metal organic framework (MOFs)-based materials for antibiotics removal via adsorption and photocatalysis

Antibiotic abuse has led to serious water pollution and severe harm to human health; therefore, there is an urgent need for antibiotic removal from water sources. Adsorption and photodegradation are two ideal water treatment methods because they are cheap, simple to operate, and reusable. Metal organic frameworks (MOFs) are excellent adsorbents and photocatalysts because of their high porosity, adaptability, and good crystal form. The aim of this study is to suggest ways to overcome the limitations of adsorption and photocatalysis treatment methods by reviewing previous applications of MOFs to antibiotic adsorption and photocatalysis. The different factors influencing these processes are also discussed, as well as the various adsorption and photocatalysis mechanisms. This study provides a valuable resource for researchers intending to use MOFs to remove antibiotics from water bodies.

Interaction of Carboxyalkylated Cellulose Nanocrystals and Antibiotics

Although antibiotics are beneficial for treating infections, their release into the environment has raised global concerns. In this work, the interactions of cellulose nanocrystal (CNC) derivatives with sulfamethoxazole (SMX), ciprofloxacin (CIP), and doxycycline (DOX) antibiotics were studied fundamentally. CNC was carboxyalkylated to bear different carbon chain lengths but similar negative charges on its surface. The highest level of adsorption of DOX on the carboxypantadecanated CNC (i.e., carboxyalkylated CNC with more carbon spacer, PCNC) occurred at pH 6.0, which was due to the electrostatic and π interactions along with hydrogen bonding. The contact angle and quartz crystal microbalance (QCM) adsorption analyses revealed a faster interaction and adsorption of DOX than other antibiotics on PCNC. The results also depicted the diffusion of DOX into the porous structure of CNC derivatives, especially that of PCNC. Also, a more compact adsorbed layer of DOX was formed on PCNC than on other CNC derivatives. Carboxyalkylation was observed to slightly reduce the surface area of CNC, while the antibiotic adsorption drastically increased the surface area of CNC due to their adsorption on the surface. XPS analysis revealed that carboxyalkylation significantly enhanced the C-C/C-H bond, while antibiotic adsorption on PCNC enhanced C-N/C-O and C-C/C-H bonds in antibiotic-loaded CNC samples. Overall, carboxyalkylated CNC was observed to have an outstanding affinity for capturing antibiotics, especially DOX, which could pave the way for the use of CNC in such applications that surface/antibiotic interactions were essential.

Self-decoration of N-doped graphene oxide 3-D hydrogel onto magnetic shrimp shell biochar for enhanced removal of hexavalent chromium

In this work, a novel decorated and combined N-doped graphene oxide hydrogel with shrimp shell magnetic biochar (NGO3DH-MSSB) biosorbent was fabricated as an effective material for Cr(VI) removal. Three-dimensional self-assembled graphene oxide hydrogel was synthesized using nitrogen source, ethylenediamine (EDA). Characterizations of NGO3DH-MSSB biosorbent were established by FT-IR, TGA, SEM and BET, where high surface area (398.05 m²/g) compared with that of MSSB (138.64 m²/g) was characterized. The maximum achieved swelling ratio (800%) was only after 300 min. The binding mechanisms between Cr(VI) ions and NGO3DH-MSSB biosorbent were controlled by electrostatic adsorption (ion-pair), pore filling, and reduction-coordination reaction. Adsorption was described by the pseudo-second order kinetic (R² =0.9994, 0.9983 and 0.9992) at 10, 50 and 100 mg/L and Langmuir isotherm model (R² =0.9997, 0.9957 and 0.9912) at 25, 40 and 50 °C. The adsorption capacity (350.42 mg/g) was achieved at pH 1.0, using initial Cr(VI) concentration (100 mg/L) and contact time (180 min) at room temperature. NGO3DH-MSSB biosorbent could be successfully reused after eight cycles. The percentage removal of Cr(VI) were confirmed as 99.79%, 99.20% and 98.00% from tap water, sea water and wastewater, respectively.

Stepwise Assembly Protocols for the Rational Design of Lanthanide Functionalized Carbon Dots-Hydrogel and its Sensing Evaluation

Inorganic-organic optical probe based on lanthanide emission will provide a new way for specific applications. In this work, sarcosine and urea are selected as raw materials to synthesize carbon dots with cyan-emissive color. In the next step, indicator components (Ethylene Diamine Tetraacetic Acid and lanthanide ions) are incorporated onto carbon quantum dots (CQDs) and the flexible alginate hydrogel is employed as the host to accommodate the emissive species. The soft material can exhibit typical red and green emissions. Its luminescence is responsive to calcium ions and the detection limit has been calculated to be 0.84 μM and 0.92 μM respectively. Such optical device can be employed as a portable probe in a variety of scientific fields due to its convenience and flexibility.

Synthesis of Magnetic Metal-Organic Frame Material and Its Application in Food Sample Preparation

A variety of contaminants in food is an important aspect affecting food safety. Due to the presence of its trace amounts and the complexity of food matrix, it is very difficult to effectively separate and accurately detect them. The magnetic metal-organic framework (MMOF) composites with different structures and functions provide a new choice for the purification of food matrix and enrichment of trace targets, thus providing a new direction for the development of new technologies in food safety detection with high sensitivity and efficiency. The MOF materials composed of inorganic subunits and organic ligands have the advantages of regular pore structure, large specific surface area and good stability, which have been thoroughly studied in the pretreatment of complex food samples. MMOF materials combined different MOF materials with various magnetic nanoparticles, adding magnetic characteristics to the advantages of MOF materials, which are in terms of material selectivity, biocompatibility, easy operation and repeatability. Combined with solid phase extraction (SPE) technique, MMOF materials have been widely used in the food pretreatment. This article introduced the new preparation strategies of different MMOF materials, systematically summarizes their applications as SPE adsorbents in the pretreatment of food contaminants and analyzes and prospects their future application prospects and development directions.