Highlights in Interface of Wastewater Treatment by Utilizing Metal Organic Frameworks: Purification and Adsorption Kinetics

Evaluating the Effect of Resorcin[4]Arenes Conformational Structures on the Remediation of Methylene Blue in Water

In this study, the effects of resorcin[4]arenes/cavitand structural properties: (i) hydrophobicity, aliphatic alkyl tails elongation (methyl, propyl, hexyl, and nonyl) based on macrocycles 1-4 lower rims; (ii) H-bond and dipole-dipole importance, resorcin[4]arene 4 vs its rigid core structure cavitand 5; and (iii) cavity order/disorder, crown (C 4v) 4 vs chair (C 2h) 6 isomers on the remediation of methylene blue (MB) in water have been investigated. Additionally, the adsorption kinetics/isotherms of MB by octols 1-4 were studied, indicating that the adsorption process follows pseudo-second order and Langmuir models, respectively. Notably, the longest alkylated crown (C 4V) conformer 4 was found to be the best adsorbent among the studied macrocycle family with a remarkable adsorption capacity (Q max = 769.230 mg/g), owing to its unique structural features and tail-to-tail aggregation behavior in water. Hence, resorcin[4]arene 4 was further used to evaluate its adsorption efficiency toward other (non)ionic dyes, and the results were considerable. Also, its recoverability/reusability toward MB removal from water was examined for five consecutive cycles, and the results revealed a promising recovering capability with excellent adsorption efficiency, leading to confidence in its effective use for manifold adsorption/desorption cycles.

Tailored Fibrils Approach via Ag(I).Peptidomimetic-Based Interface Design: Efficient Encapsulation of Diverse Active Pharmaceutical Ingredients in Wastewater Remediation during Effluent Treatment Plant (ETP) Processing

Pharmaceutical pollution in wastewater poses significant environmental and public health concerns worldwide. Chloramphenicol (CP), an antibiotic widely used in medical and veterinary applications, is among the active pharmaceutical ingredients (APIs) frequently detected in aquatic environments. This study explored the encapsulation of chloramphenicol API in contaminated wastewater using rationally designed fibrations based on the silver metal ion-directed self-assembly of fibrillator-type self-assembling ligand (ANS-3). We further investigated the removal of various commonly prescribed drugs, including antibiotics such as β-lactam (amoxicillin), fluoroquinolone (ciprofloxacin), aminoglycoside (neomycin), and tetracycline; antiparasitic agents with antiprotozoal properties (praziquantel and metronidazole); nonsteroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone and ketoprofen; the vasodilator isoxsuprine; amphiphilic antidepressants (amitriptyline); and the antiviral drug amantadine. The findings validated the crucial influence of polar multifunctionality and structural complexity in enhancing interactions with Ag.ANS-3 matrix, emphasizing its potential for efficient drug sequestration. First, picolinic acid (PA) and phenylalanine (F) were evaluated for their ability to form fibrillar structures, and their morphological characterization revealed well-defined fibrillar networks with varying degrees of porosity and interconnectivity. Then, the strategic inclusion of leucine in synthesizing ANS-3 facilitated the formation of robust fibrillar networks, employing its hydrophobic interactions to drive the self-assembly process. Finally, the encapsulation of APIs was evaluated using Ag(I) metal ion-driven ANS-3 based self-assembled nanofibrous material. This research contributes to the development of innovative physicochemical wastewater treatment strategies for environmental remediation and validates the importance of rational design in encapsulation-based wastewater remediation technologies.

Facile Synthesis of Silsesquioxane-Based Hybrid Crosslinked Polymers via One-Step Amine-Ene Reaction for Efficient Adsorption of Various Pollutants

The rapid advancement of industrial production has led to an increase in water pollutants, posing a significant threat to public health. With the deepening of research on pollutant adsorbents. The application of silsesquioxane-based cross-linked polymer networks in water pollution treatment has gradually attracted people's attention. This study introduces two new crosslinked hybrid network, PCS-OB and PCS-OP, which were created through one-step amine-ene reaction between octa(aminophenyl) silsesquioxane (OAPS) and bismaleimide or N, N'-1,3-phenylenedimaleimide. The synthesized hybrid networks were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and solid-state nuclear magnetic resonance (NMR) spectroscopy. The successful synthesis of the material is proved. PCS-OB and PCS-OP exhibited remarkable efficiency in the adsorption and removal of contaminants such as antibiotics, dyes, and iodine from wastewater. The maximum adsorbents for Rhodamine B (RhB), iodine vapor and berberine hydrochloride (BCH) were 1069 mg g-1, 1590 mg g-1 and 294 mg g-1, respectively. In conclusion, this work proves that PCS-OB and PCS-OP have broad application prospects in pollutant treatment.

An Adsorbent for Efficient and Rapid Gold Recovery from Solution: Adsorption Properties and Mechanisms

Adsorption is an efficient and highly selective method for gold recovery. Introducing rich N/S organic groups to combine with metal-organic frameworks (MOFs) as adsorbents is regarded as a practical and efficient approach to enhance gold recovery. Herein, a MOF (zirconium isothiocyanatobenzenedicarboxylate MOF, UiO-66-NCS) was designed to combine with amidinothiourea (AT) to form UiO-66-AT (zirconium amidothiourea-benzenedicarboxylate MOF) for efficient and rapid adsorption. The prepared UiO-66-AT delivers an improved adsorption capacity (about 903.02 mg/g at 1000 mg·L-1 of the initial Au3+) and an impressive adsorption rate within minutes (about 10 min for 200 mg·L-1 Au3+). Meanwhile, it exhibits sustainable stability after 5 cycles with a retention rate of 99.52% and excellent adsorption selectivity of 98.76% in actual wastewater. According to advanced characterizations and Density Functional Theory (DFT) simulation, the mechanism might be elaborated as electrostatic adsorption, chelating coordination, and chemical reduction. The modified active groups of the MOF provide the adsorption sites for Au(III) and the rapid reduction of Au(0). UiO-66-AT maintains a large adsorption capacity and high surface reduction activity while realizing stable application in multiple cycles, which is of good practical application value.

Sustainable polymeric adsorbents for adsorption-based water remediation and pathogen deactivation: a review

Water is a fundamental resource, yet various contaminants increasingly threaten its quality, necessitating effective remediation strategies. Sustainable polymeric adsorbents have emerged as promising materials in adsorption-based water remediation technologies, particularly for the removal of contaminants and deactivation of water-borne pathogens. Pathogenetic water contamination, which involves the presence of harmful bacteria, viruses, and other microorganisms, poses a significant threat to public health. This review aims to analyze the unique properties of various polymeric materials, including porous aromatic frameworks, biopolymers, and molecularly imprinted polymers, and their effectiveness in water remediation applications. Key findings reveal that these adsorbents demonstrate high surface areas, tunable surface chemistries, and mechanical stability, which enhance their performance in removing contaminants such as heavy metals, organic pollutants, and emerging contaminants from water sources. Furthermore, the review identifies gaps in current research and suggests future directions, including developing multifunctional polymeric materials and integrating adsorption techniques with advanced remediation technologies. This comprehensive analysis aims to contribute to advancing next-generation water purification technologies, ensuring access to clean and safe water for future generations.

Standalone Highly Efficient Graphene Oxide as an Emerging Visible Light-Driven Photocatalyst and Recyclable Adsorbent for the Sustainable Removal of Organic Pollutants

Carbon-based nanostructures are promising eco-friendly multifunctional nanomaterials because of their tunable surface and optoelectronic properties for a variety of energy and environmental applications. The present study focuses on the synthesis of graphene oxide (GO) with particular emphasis on engineering its surface and optical properties for making it an excellent adsorbent as well as a visible light-active photocatalyst. It was achieved by modifying the improved Hummers method through optimizing the synthesis parameters involved in the oxidation process. This controlled synthesis allows for systematic tailoring of structural, optical, and surface functionality, leading to improved adsorption and photocatalytic properties for the sustainable removal of organic pollutants in water treatment. Several spectroscopic and microscopic characterization techniques, such as XRD, SEM, Raman, UV-visible, FTIR, TEM, XPS, BET, etc. were employed to analyze the degree of oxidation, surface chemistry/functionalization, morphological, optical, and structural properties of the synthesized GO nanostructures. The analyses showed excellent surface functionality with surface active sites for better adsorptive removal and a tunable band gap from 2.51 to 2.76 eV exhibiting excellent natural sunlight activity (>99%) for photocatalytic removal of the organic pollutant. Various adsorption isotherms have been studied with excellent adsorption capability (Qmax = 454.54 mg/g) as compared to the literature. The study introduces GO both as a proficient stand-alone (sole) nanoadsorbent as well as a nanophotocatalyst for the efficient removal of organic dye pollutants in water treatment. Additionally, the article highlights the sustainable solar light-induced green chemistry aspects of GO as an excellent recyclable adsorbent as a result of its self-cleaning ability under natural sunlight, demonstrating its potential in real eco-friendly environmental and practical applications.

Adsorption Behavior and Mechanism of Palladium on Diethylaminoethyl-Modified Polyglycidyl Methacrylate Macroporous Spheres

The recovery of precious metals, such as palladium (Pd), from wastewater, is an economically important field. The present study reports the application of polyglycidyl methacrylate (PGMA) macroporous spheres with diethylaminoethyl (DEAE) functional groups (PGMA-DEAE) for the adsorption of palladium ions [Pd(II)] from simulated wastewater solutions. The effects of pH, adsorption duration, and initial concentration of Pd(II) on the adsorption amount were evaluated systematically. The results revealed that within the experimental pH range, the adsorption efficiency of Pd(II) increased with increasing pH. In particular, between pH 4 and 6, the Pd(II) adsorption efficiencies were approximately 100%. At 298 K and pH ∼ 4, the adsorption capacity of PGMA-DEAE for Pd(II) was 1.22 mmol/g. The adsorption rates of PGMA-DEAE for Pd(II) were high, and the adsorption equilibrium was reached within 10 min. Ca(II), Mg(II), Co(II), Cu(II), Ni(II), and Fe(II) were selected as representative competitive adsorption metal ions. PGMA-DEAE had good separation selectivity for Pd(II) at pH 1-6 (all RPd/Me > 30), especially at pH ∼ 4 (all RPd/Me > 100). The SEM, TEM, EDS, TG, XRD, and XPS results indicated that in a high-acidity environment (CHCl ≥ 1 mol/L), Pd(II) was adsorbed on PGMA-DEAE through electrostatic attraction, while in a low-acidity environment (pH 1-6), Pd(II) was adsorbed on PGMA-DEAE through coordinated bonding between the Pd(II) ions and the N. PGMA-DEAE exhibited excellent stability and regeneration performance for five regeneration cycles.