Green and plant-based adsorbent from tragacanth gum and carboxyl-functionalized carbon nanotube hydrogel bionanocomposite for the super removal of methylene blue dye

Highly effective removal of basic fuchsin dye using carboxymethyl konjac glucomannan grafted acrylic acid-acrylamide/montmorillonite composite hydrogel

This study developed a nanocomposite hydrogel, CAM4-MMT, for efficiently removing basic fuchsin dye from water. The hydrogel was prepared by grafting a copolymer of acrylic acid (AA) and acrylamide (AM) onto carboxymethyl konjac glucomannan (CMKGM), and doped with montmorillonite (MMT), exhibited excellent thermal stability, a porous inner structure, large specific surface area (1.407 m2/g), and high swelling capacity (107.3 g/g). The hydrogel achieved a maximum adsorption capacity of 694.1 mg/g and a removal rate of 99.5 %. The Langmuir isotherm and pseudo-second-order kinetic model best described the adsorption process. Regeneration and reuse tests confirmed that the hydrogel has excellent recyclability. In conclusion, the CAM4-MMT composite hydrogel efficiently removed basic fuchsin from water solutions, offering a new scheme for eliminating basic fuchsin using natural polysaccharides with promising applications.

Recent advancements and prospects in carbon-based nanomaterials derived from biomass for environmental remediation applications

The conversion of waste biomass into a value-added carbonaceous nanomaterial highlights the appealing power of biomass valorization. The advantages of using sustainable and cheap biomass precursors exhibit the tremendous opportunity for boosting energy production and their application in environmental remediation processes. This review emphasis the development and production of carbon-based nanomaterials derived from biomass, which possess favourable characteristics such as biocompatibility and photoluminescence. The advantages and limitations of various nanomaterials synthesised from different precursors were also discussed with insights into their physicochemical properties. The surface morphology of the porous nanomaterials is also explored along with their characteristic properties like regenerative nature, non-toxicity, ecofriendly nature, unique surface area, etc. The incorporation of various functional groups confers superiority of these materials, resulting in unique and advanced functional properties. Further, the use of these biomass derived nanomaterials was also explored in different applications like adsorption, photocatalysis and sensing of hazardous pollutants, etc. The challenges and outcomes obtained from different carbon-based nanomaterials are briefly outlined and discussed in this review.

Natural gums and their derivatives based hydrogels: in biomedical, environment, agriculture, and food industry

The hydrogels based on natural gums and chemically derivatized natural gums have great interest in pharmaceutical, food, cosmetics, and environmental remediation, due to their: economic viability, sustainability, nontoxicity, biodegradability, and biocompatibility. Since these natural gems are from plants, microorganisms, and seaweeds, they offer a great opportunity to chemically derivatize and modify into novel, innovative biomaterials as scaffolds for tissue engineering and drug delivery. Derivatization improves swelling properties, thereby developing interest in agriculture and separating technologies. This review highlights the work done over the past three and a half decades and the possibility of developing novel materials and technologies in a cost-effective and sustainable manner. This review has compiled various natural gums, their source, chemical composition, and chemically derivatized gums, various methods to synthesize hydrogel, and their applications in biomedical, food and agriculture, textile, cosmetics, water purification, remediation, and separation fields.

Current trends in textile wastewater treatment-bibliometric review

A bibliometric study using 1992 to 2021 database of the Science Citation Index Expanded was carried out to identify which are the current trends in textile wastewater treatment research. The study aimed to analyze the performance of scholarly scientific communications in terms of yearly publications/citations, total citations, scientific journals, and their categories in the Web of Sciences, top institutions/countries and research trends. The annual publication of scientific articles fluctuated in the first ten years, with a steady decrease for the last twenty years. An analysis of the most common terms used in the authors' keywords, publications' titles, and KeyWords Plus was carried out to predict future trends and current research priorities. Adsorbent nanomaterials would be the future of wastewater treatment for decoloration of the residual dyes in the wastewater. Membranes and electrolysis are important to demineralize textile effluent for reusing wastewater. Modern filtration techniques such as ultrafiltration and nanofiltration are advanced membrane filtration applications.

Advances in gum-based hydrogels and their environmental applications

Gum-based hydrogels (GBHs) have been widely employed in diverse water purification processes due to their environmental properties, and high absorption capacity. More desired properties of GBHs such as biodegradability, biocompatibility, material cost, simplicity of manufacture, and wide range of uses have converted them into promising materials in water treatment processes. In this review, we explored the application of GBHs to remove pollutants from contaminated waters. Water resources are constantly being contaminated by a variety of harmful effluents such as heavy metals, dyes, and other dangerous substances. A practical way to remove chemical waste from water as a vital component is surface adsorption. Currently, hydrogels, three-dimensional polymeric networks, are quite popular for adsorption. They have more extensive uses in several industries, including biomedicine, water purification, agriculture, sanitary products, and biosensors. This review will help the researcher to understand the research gaps and drawbacks in this field, which will lead to further developments in the future.

Synthesis and Characterization of Orange Peel Modified Hydrogels as Efficient Adsorbents for Methylene Blue (MB)

In recent years, due to the developments in the textile industry, water contaminated with synthetic dyes such as methylene blue (MB) has become an environmental threat based on the possible impacts in terms of chemical and biochemical demand, which leads to disturbance in aquatic plants photosynthesis, besides their possible toxicity and carcinogenicity for humans. In this work, an adsorbent hydrogel is prepared via free radical polymerization comprising acrylic acid (PAA) as a monomer and orange peel (OP) as a natural modifier rich in OH and COOH present in its cellulose and pectin content. The resulting hydrogels were optimized in terms of the content of OP and the number of cross-linkers and characterized morphologically using Scanning electron microscopy. Furthermore, BET analysis was used to follow the variation in the porosity and in terms of the surface area of the modified hydrogel. The adsorption behavior was found to follow pseudo-second-order as a kinetic model, and Langmuir, Freundlich, and Temkin isotherm models. The combination of OP and PAA has sharply enhanced the adsorption percent of the hydrogel to reach 84% at the first 10 min of incubation with an adsorption capacity of more than 1.93 gm/gm. Due to its low value of pHPZc, the desorption of MB was efficiently performed at pH 2 using HCl, and the desorbed OP-PAA were found to be reusable up to ten times without a decrease in their efficiency. Accordingly, OP-PAA hydrogel represents a promising efficient, cost-effective, and environmentally friendly adsorbent for MB as a model cationic dye that can be applied for the treatment of contaminated waters.

Probing and Manipulating Noncovalent Interactions in Functional Polymeric Systems

Noncovalent interactions, which usually feature tunable strength, reversibility, and environmental adaptability, have been recognized as driving forces in a variety of biological and chemical processes, contributing to the recognition between molecules, the formation of molecule clusters, and the establishment of complex structures of macromolecules. The marriage of noncovalent interactions and conventional covalent polymers offers the systems novel mechanical, physicochemical, and biological properties, which are highly dependent on the binding mechanisms of the noncovalent interactions that can be illuminated via quantification. This review systematically discusses the nanomechanical characterization of typical noncovalent interactions in polymeric systems, mainly through direct force measurements at microscopic, nanoscopic, and molecular levels, which provide quantitative information (e.g., ranges, strengths, and dynamics) on the binding behaviors. The fundamental understandings of intermolecular and interfacial interactions are then correlated to the macroscopic performances of a series of noncovalently bonded polymers, whose functions (e.g., stimuli-responsiveness, self-healing capacity, universal adhesiveness) can be customized through the manipulation of the noncovalent interactions, providing insights into the rational design of advanced materials with applications in biomedical, energy, environmental, and other engineering fields.

Structure and Adsorption Performance of Cationic Entermorpha prolifera Polysaccharide-Based Hydrogel for Typical Pollutants: Methylene Blue, Cefuroxime, and Cr (VI)

Hydrogels with polysaccharides as high polymer substrates have surprising advantages in wastewater treatment with complex components. Therefore, in this study, polysaccharides named EPS were extracted from Enteromorpha prolifera, a coastal pollutant with a wide range of sources, and cationic modification was performed to obtain CAEPS, the hydrogel with a double network structure was prepared based on EPS and CAEPS. Meanwhile, the structural characteristic of EPS and CAEPS-based hydrogel were identified by HPLC, AFM, FT-IR, TGA, SEM-EDS, Pore size distribution, and WCA, which showed that the porosity, apparent (skeletal) density, and hydrophilicity of CAEPS-hydrogels. We used nonlinear isotherms to uncover the adsorption mechanism of hydrogel applied to the water environment containing three typical pollutants (Methylene blue, Cefuroxime, and Cr (VI)). The results showed that the adsorption isotherm of the two hydrogels fit the Langmuir isotherm model, which indicated the monolayer adsorption of the pollution factor onto EPS- and CAEPS-hydrogels. The maximum adsorption capacities of CAEPS-hydrogels were higher than EPS-hydrogels, which indicated the microstructure and adsorption performance of the CAEPS-hydrogel are strengthened.

Preparation and characterization of wheat straw biochar loaded with aluminium/lanthanum hydroxides: a novel adsorbent for removing fluoride from drinking water

In this work, a novel adsorbent of aluminium/lanthanum loaded wheat straw biochar (Al-La-WSB), was prepared by using a facile approach and used for fluoride removal. The Al-La-WSB and its pristine wheat straw biochar (WSB) were characterized by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray powder diffraction (XRD) methods. Batch adsorption experiments were carried out to investigate adsorbent performance, the highest removal rate was observed at pH 9, contact time of 7 h and Al-La-WSB dose of 1 g L^-1. Lagergren pseudo-second-order kinetics and Langmuir isotherm model fitted the experimental data well. The maximum fluoride adsorption capacity of Al-La-WSB at different experiment temperature of 298, 308 and 318 K, was 51.28 mg g^-1, 46.73 mg g^-1 and 50.25 mg g^-1, respectively, which was better than most reported adsorbents. The Al-La-WSB performed well over a considerable wide pH range of 3-10 and carried positive charge at pH < 4.8. The presence co-existing ions of SO₄^2-, HCO₃^-, Cl^- and NO₃^- had a minor impact on fluoride adsorption besides PO₄^3-. Regeneration experiment results showed that the Al-La-WSB had an excellent reusability. According to the adsorbent characterization and batch adsorption experiment, the adsorption of fluoride on the Al-La-WSB was primarily a chemisorption, involving electrostatic interactions and ion exchange, which nitrate ion and hydroxyl played a major role. The results suggested that the Al-La-WSB could be a great adsorbent for removing fluoride from drinking water.

Lightweight and anisotropic cellulose nanofibril/rectorite composite sponges for efficient dye adsorption and selective separation

Constructing lightweight and porous adsorbents which can effectively remove dye contaminants is of great significance in the field of the sewage treatment. In this work, anisotropic cellulose nanofibril (CNF) composite sponges assisted by rectorites are fabricated through directional freeze-drying. The resulted composite sponge exhibits the superior saturated adsorption capacity and removal efficiency of 120.0 mg/g and 96.1% for methylene blue (MB), respectively, which is better than the pure CNF sponge and rectorite powders. This is attributed to the strong electrostatic interaction between CNFs and MB, and good cation exchange property of rectorites inside the three-dimensional (3D) highly porous composite sponge. The MB adsorption process of the composite sponge fits to the pseudo-second-order kinetic model and the Langmuir isotherm model well, which is affected by both boundary layer and intraparticle diffusion, resulting in a theoretical maximum adsorption capacity of 214.6 mg/g. Moreover, it also possesses a selective adsorption capacity for anionic and cationic dyes, which is expected to realize the separation treatment of different dyes according to actual application requirements.

Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field

The performance of Carbon Nanotubes hybrid hydrogels for environmental remediation was investigated using Methylene Blue (MB), Rhodamine B (RD), and Bengal Rose (BR) as model contaminating dyes. An acrylate hydrogel network with incorporated CNT was synthesized by photo-polymerization without any preliminary derivatization of CNT surface. Thermodynamics, isothermal and kinetic studies showed favorable sorption processes with the application of an external 12 V electric field found to be able to influence the amount of adsorbed dyes: stronger interactions with cationic MB molecules (qexp and qexp12 of 19.72 and 33.45 mg g⁻¹, respectively) and reduced affinity for anionic RD (qexp and qexp12 of 28.93 and 13.06 mg g⁻¹, respectively) and neutral BR (qexp and qexp12 of 36.75 and 15.85 mg g⁻¹, respectively) molecules were recorded. The influence of pH variation on dyes adsorption was finally highlighted by reusability studies, with the negligible variation of adsorption capacity after five repeated sorption cycles claiming for the suitability of the proposed systems as effective sorbent for wastewater treatment.

Evaluation of gum ghatti-g-poly(itaconic acid) magnetite nanocomposite as an adsorbent material for water purification

A porous hydrogel nanocomposite has been made by grafting poly(itaconic acid) on the polysaccharide, gum ghatti and by embedding magnetite nanoparticles in the copolymer gel matrix. This novel functional material Ggh-g-PIA/Fe₃O₄ was characterized by FTIR, TGA, SEM, EDS, XRD, BET, Zeta potential measurements and VSM techniques. The nanocomposite possesses mesoporous structure with high surface area and exhibits super-paramagnetic behavior due to the presence of magnetite nanoparticles. The hydrogel nanocomposite was evaluated as an adsorbent material for removal of dyes and divalent metal ions. Significant adsorption capacities of 410.2, 387.6, 416.5 and 401.4 mg g^-1 towards methylene blue, rhodamine 6G, Cu (II) and Hg (II) ions respectively were observed. The adsorption isotherms were well described by the Freundlich isotherm model and kinetic studies demonstrated the adsorption to be a pseudo second order kinetic process. Intraparticle diffusion model suggested adsorption to occur by a multi-step diffusion process. Thermodynamic studies indicated a spontaneous and endothermic adsorption. Further, the desorption study indicated the possibility of successful regeneration of the adsorbent. A high removal efficiency, recyclability, convenient recovery after use due to the magnetic nature makes this polysaccharide based nanocomposite an environment friendly adsorbent material for water purification.

Development of Arabic gum-based AgTiO2 nanocomposite hydrogel as high efficient adsorbent of cationic dye methylene blue from water

The chemically crosslinked silver titanium dioxide embedded Arabic gum grafted polyacrylamide-polyacrylonitrile nanocomposite AgTiO₂@AG-g-P(AM-co-AN)was successfully synthesized and investigated by ATR-IR, XRD, and SEM. The synthesis optimization parameters of AG-g-P(AM-co-AN)were 5% AG, 1/0.5 AM/AN monomer molar ratio, 0.5 mg MBA cross-linker, and AgTiO₂ content (1%) gives AgTiO₂@AG-g-P(AM-co-AN) nanocomposite. While adsorption studies for AgTiO₂@AG-g-P(AM-co-AN) exhabited the maximum adsorption capacity (104.50 ± 3.02 mg/g) at concentration (150 mg/L), MB concentration (15 mg/L) and pH (8.0). The adsorption nonlinear kinetics models were used. Pseudo-second order governs the adsorption process, and the Langmuir model is more suited than Freundlich and Temkin.

3D and 4D printing: From innovation to evolution

The world and science are moving forward nonstop. Every day, we see novel technologies that are coming to improve life quality. One of them is 3D printing or additive manufacturing. This technology covers the shortage of the current manufacturing technologies, and it has been enhanced by introducing smart materials like smart polymers as feed. The following product can adapt to circumstance conditions such as temperature changes, compression alteration, etc. These responses resulted in an advanced 3D printing technology called 4D printing. 3D and 4D printing technologies found their applications in all areas and industry sizes, from home-scale to large-scale industries. Regardless of all advantages of these technologies, there are still some shortages like low printing speed. But this never stops their progression and promotion. In this review, we aimed to cover general knowledge about 3D and 4D printing and their recent applications in various fields.

Effective adsorption of methylene blue dye from water solution using renewable natural hydrogel bionanocomposite based on tragacanth gum: Linear-nonlinear calculations

Today, hydrogels opened new windows to the high-tech due to their amazing features. Thus, we applied hydrogel nanocomposite (HNC) made of tragacanth gum (a kind of polysaccharide) and CaCO₃ nanoparticles to remove methylene blue dye (MBD) from the water solution. We used nonlinear and linear isotherms and kinetics as well as thermodynamics to uncover the adsorption mechanism. The results showed that the hydrogel could remove 80% of MBD. Besides, the linear form of the pseudo-second-order kinetic model fits well with the results, showing chemical interactions. We found that this process follows both Sips and Redlich-Peterson models by applying nonlinear and linear isotherm models. The maximum adsorption capacities from nonlinear and linear Sips were 1401 and 2145 mg/g, respectively. Based on the thermodynamic equations, the adsorption of MBD onto HNC was physiochemical and exothermic. According to the phenomenological calculations, diffusion from the bulk (or film diffusion, D_f = 1.2 × 10^-8 cm²/s) is the primary mechanism.

Fight against COVID-19 pandemic with the help of carbon-based nanomaterials

We have considered the newest momentous outcomes in carbon-based nanomaterials for utility in controlling and fighting the SARS-CoV-2 virus.

Emerging new-generation hybrids based on covalent organic frameworks for industrial applications

This review highlights the advancement of COF hybrid-based materials for diverse industrial applications.