Herein, porous sodium alginate/graphite based hybrid hydrogel was fabricated as an effective adsorbent for organic pollutant. Sodium alginate was modified through graft polymerization of acrylic acid and subsequently loaded with graphite powder to enhance its adsorption capability. The synthesized sodium alginate cross-linked acrylic acid/graphite (NaA-cl-AAc/GP) hydrogel composite was utilized in the removal of malachite green (MG) dye from aqueous solution using batch adsorption experiments. The NaA-cl-AAc/GP hydrogel composite was characterized by infrared spectroscopy, Raman spectroscopy, thermo-gravimetric analysis, scanning electron microscopy, x-ray photoelectron spectroscopy and x-ray diffraction. Under optimized experimental conditions, a maximum adsorption capacity of 628.93 mg g−1 was attained for malachite green dye. Moreover, the adsorption process could be well described by the Langmuir isotherm model and pseudo-second-order kinetic model. The hydrogel composite also showed 91\% adsorption after three consecutive cycles of dye adsorption-desorption. Therefore, the NaA-cl-AAc/GP hydrogel composite is a potentially favourable material towards dye pollution remediation owing to its better swelling rate, environment friendliness, high adsorption potential and regeneration capability. © 2020 Elsevier B.V.

Verma A.

Thakur S.

Mamba G.

Prateek

Gupta R.K.

Thakur P.

Thakur V.K.

Fulltext

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

International Journal of Biological Macromolecules

In this work, 2-hydroxyethyl methacrylate cross-linked gum tragacanth hydrogel (GumT-cl-HEMA) was systematically synthesized to attain maximum swelling (396.9 \%) by simple microwave-assisted green polymerization technique. The prepared GumT-cl-HEMA hydrogel was further modified by using TiO2 nanoparticles to generate TiO2 loaded 2-hydroxyethyl methacrylate cross-linked gum tragacanth (GumT-cl-HEMA/TiO2) hydrogel composite. The GumT-cl-HEMA hydrogel and GumT-cl-HEMA/TiO2 hydrogel composite were characterized through XPS, BET, XRD, FTIR, TGA and SEM. The GumT-cl-HEMA hydrogel and GumT-cl-HEMA/TiO2 hydrogel composite were used to perform adsorption to separate the molecules of malachite green (MG) from water. Batch adsorption parameters were examined to analyze the pH effect, time effect and adsorbent dose for the adsorption of malachite green dye from aqueous solution. The inclusion of TiO2 particles inside the GumT-cl-HEMA hydrogel led to increased adsorption rates and stability. The adsorption was accurately followed the pseudo second order model and Langmuir isotherm model. The reported GumT-cl-HEMA/TiO2 hydrogel composite removal efficiency was 99.3 \% adsorbent dose = 90 mg, MG = 50 ppm, pH = 7, volume = 50 mL and time = 80 min). The synthesized samples were regenerated and then reused for five repeated adsorption-desorption cycles. The construction of GumT-cl-HEMA hydrogel and GumT-cl-HEMA/TiO2 hydrogel composite gives a facile scheme for efficient adsorbents. © 2020 Elsevier Ltd.

Journal of Environmental Chemical Engineering

Titania modified gum tragacanth based hydrogel nanocomposite for water remediation

Downgrading in the yield of crop is due to the inadequate availability of water. The way out for this trouble is to construct synthetic resources dependent on natural polymers with great water absorption and preservation limits. The present study investigated the design of agar-agar (Agr) and gelatin (GE) copolymerized methyl acrylate (MA) and acrylic acid (AA) hydrogel (Agr/GE-co-MA/AA) as a soil conditioner for moisture maintenance in agriculture. Agr/GE-co-MA/AA hydrogel was prepared by utilizing microwave-assisted green synthesis following the most suitable reaction conditions to obtain a remarkable water swelling percentage. The fabricated Agr/GE-co-MA/AA hydrogel was investigated through field emission scanning electron microscopy (FESEM), fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The water holding capacity of the soil and sand was examined by mixing Agr/GE-co-MA/AA hydrogel with soil and sand. The result demonstrates that the water holding time extended from 10 to 30 days for soil and 6 to 10 days for sand by using Agr/GE-co-MA/AA hydrogel. This synthesized biodegradable, low-cost and non-toxic Agr/GE-co-MA/AA hydrogel shows novelty as soil water maintaining material for irrigation in agriculture. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Biomolecules

Development of biodegradable agar-agar/gelatin-based superabsorbent hydrogel as an efficient moisture-retaining agent

Researchers have recently focused on the advancement of new materials from biorenewable and sustainable sources because of great concerns about the environment, waste accumulation and destruction, and the inevitable depletion of fossil resources. Biorenewable materials have been extensively used as a matrix or reinforcement in many applications. In the development of innovative methods and materials, composites offer important advantages because of their excellent properties such as ease of fabrication, higher mechanical properties, high thermal stability, and many more. Especially, nanocomposites (obtained by using biorenewable sources) have significant advantages when compared to conventional composites. Nanocomposites have been utilized in many applications including food, biomedical, electroanalysis, energy storage, wastewater treatment, automotive, etc. This comprehensive review provides chemistry, structures, advanced applications, and recent developments about nanocomposites obtained from biorenewable sources. Copyright © 2020 American Chemical Society.

Chemical Reviews

Chemistry, structures, and advanced applications of nanocomposites from biorenewable resources

Reduced graphene oxide (RGO) was synthesized in this research via Tour’s method for the use of filler in the hydrogel matrix. The copolymerization of N,N-dimethylacrylamide (DMA) onto the gum tragacanth (GT) was carried out to develop gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)) hydrogel using N,N’-methylenebisacrylamide (NMBA) and potassium persulfate (KPS) as cross-linker and initiator correspondingly. The various GT-cl-poly(DMA) hydrogel synthesis parameters were optimized to achieve maximum swelling of GT-cl-poly(DMA) hydrogel. The optimized GT-cl-poly(DMA) hydrogel was then filled with RGO to form reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)/RGO) hydrogel composite. The synthesized samples were used for competent adsorption of Hg2+ and Cr6+ ions. Fourier transform infrared, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy were used to characterize the gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. The experiments of adsorption-desorption cycles for Hg2+ and Cr6+ ions were carried out to perform the reusability of gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. From these two samples, reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide exhibited high adsorption ability. The Hg2+ and Cr6+ ions adsorption by gum tragacanth-cl-N,N-dimethylacrylamide and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide were best suited for pseudo-second-order kinetics and Langmuir isotherm. The reported maximum Hg2+ and Cr6+ ions adsorption capacities were 666.6 mg g-1 and 473.9 mg g-1 respectively. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Nanomaterials

Microwave-assisted rapid synthesis of reduced graphene oxide-based gum tragacanth hydrogel nanocomposite for heavy metal ions adsorption

Pectin is one of the finest natural polymer which has drawn great attention because of its applications in different fields. Due to the quintessential structure of pectin, it can be transformed into variety of useful products. It can be utilized as a blend in many polymers to make a mixture or a composite material. Owing to considerable collection in chemical conformation and cross-linking mechanism, different pectin based hydrogels have been prepared for different characteristics in pharmaceutical and bio-medical sites. Inventive properties of hydrogels like volubility, swellability, solvability and hydrophilicity make them better alternative for wastewater treatment. Recently, pectin based hydrogels have demonstrated excellent performance to eliminate various metal ions and dyes from the polluted water. The adsorption characteristics of pectin based hydrogels can be upgraded by using nanoparticles, which prompts to the development of hydrogel nano-composites. In this review article, we have summarized a comprehensive assessment in the direction of using pectin based hydrogels to remove toxic pollutants from aqueous solution. Sodium acrylate-co-N-isopropylacrylamide based pectin hydrogel has demonstrated the maximum adsorption capacities of 265.49, 137.43, 54.86, 53.86, 51.72 and 50.01 mg g −1 for the adsorption of methyl violet, methylene blue, Pb(II), Cu(II), Co(II) and Zn(II) respectively. We have also discussed the pectin structure, properties and applications in this article. © 2019 Elsevier Ltd

Journal of Environmental Management

Progress in pectin based hydrogels for water purification: Trends and challenges

Journal of Colloid and Interface Science

A novel 3D yttrium based-graphene oxide-sodium alginate hydrogel for remarkable adsorption of fluoride from water

International Journal of Polymer Analysis and Characterization

Recent approaches in guar gum hydrogel synthesis for water purification

Journal of Cleaner Production

Recent progress in sodium alginate based sustainable hydrogels for environmental applications

Current Opinion in Green and Sustainable Chemistry

Recent developments in recycling of polystyrene based plastics

Graphite modified sodium alginate hydrogel composite for efficient removal of malachite green dye