Synthesis, characterization and photo-catalytic activity of guar-gum-g-aliginate@silver bionanocomposite material

Applications of guar gum polysaccharide for pharmaceutical drug delivery: A review

Bio-based materials are rapidly replacing synthetic materials owing to their significant biomedical applications, easy availability, nontoxicity, biodegradability and biocompatibility. Guar gum (GG) is a plant-derived biocompatible and biodegradable polymeric compound found abundantly in nature. It is a non-ionic, hydrophilic carbohydrate and is a cost-effective hydrocolloid polysaccharide considered as a wonderful representative of the new generation of plant gums. Various composites of guar gum with other polymers have been reported in last few decades and they are extensively used in different industries like food, textile, mining, petrochemical, paper and explosives etc. Easy availability, non-toxicity, eco-friendly and biodegradable nature of GG has made it ideal candidate for for drug delivery (DD) applications. GG based hydrogels, films, scaffolds and nanoparticles have been explored widely for their DD applications. These non-toxic DD carriers can be used for targeted drug delivery. This review article directs the current efforts and improvements on GG and GG-based materials to be used in DD.

Metal/metal oxide-carbohydrate polymers framework for industrial and biological applications: Current advancements and future directions

Recently, the development and consumption of metal/metal oxide carbohydrate polymer nanocomposites (M/MOCPNs) are withdrawing significant attention because of their numerous salient features. Metal/metal oxide carbohydrate polymer nanocomposites are being used as environmentally friendly alternatives for traditional metal/metal oxide carbohydrate polymer nanocomposites exhibit variable properties that make them excellent prospects for a variety of biological and industrial uses. In metal/metal oxide carbohydrate polymer nanocomposites, carbohydrate polymers bind with metallic atoms and ions using coordination bonding in which heteroatoms of polar functional groups behave as adsorption centers. Metal/metal oxide carbohydrate polymer nanocomposites are widely used in woundhealing, additional biological uses and drug delivery, heavy ions removal or metal decontamination, and dye removal. The present review article features the collection of some major biological and industrial applications of metal/metal oxide carbohydrate polymer nanocomposites. The binding affinity of carbohydrate polymers with metal atoms and ions in metal/metal oxide carbohydrate polymer nanocomposites has also been described.

Cellulose nanocrystals doped silver nanoparticles immobilized agar gum for efficient photocatalytic degradation of malachite green

The present study involves the synthesis of green functional material based on the silver nanoparticle (Ag NPs) doped cellulose nanocrystals (CNC) immobilized agar gum (AA) biopolymer using chemical coprecipitation method. The stabilization of Ag NPs in cellulose matrix and functionalization of the synthesized material through agar gum was analyzed using various spectroscopic techniques such as Fourier Transform Infrared (FTIR), Scanning electron microscope (SEM), Energy X-Ray diffraction (EDX), Photoelectron X-ray (XPS), Transmission electron microscope (TEM), Selected area energy diffraction (SAED) and ultraviolet visible (UV-Vis) spectroscopy. The XRD results suggested that the synthesized AA-CNC@Ag BNC material is composed of 47 % crystalline and 53 % amorphous nature having distorted hexagonal structure due to capping of Ag NPs by amorphous biopolymer matrix. The Debye-Scherer crystallite sized was calculated as 18 nm which is found in close agreement with TEM analysis (19 nm). The SAED yellow fringes simulates the miller indices values with XRD patterns and supported the surface functionalization of Ag NPs by biopolymer blend of AA-CNC. The XPS data supported the presence of Ag⁰ as indexed by Ag3d orbital corresponding to Ag3d_3/2 at 372.6 eV and Ag3d_5/2 at 366.6 eV. The surface morphological results revealed a flaky surface of the resultant material having well distributed Ag NPs in the matrix. The EDX and atomic concentration results given by XPS supported the presence if C, O and Ag in the bionanocomposite material. The UV-Vis results suggested that the material is both UV and visible light active having multiple SPR effects with anisotropy. The material was explored as a photocatalyst for remediation of wastewater contaminated by malachite green (MG) using advance oxidation process (AOP). Photocatalytic experiments were performed in order to optimize various reaction parameters such as irradiation time, pH, catalyst dose and MG concentration. The obtained results showed that almost 98.85 % of MG was degraded by using 20 mg of catalyst at pH 9 for 60 min of irradiation. The trapping experiments revealed that ^•O₂^- radicals played primary role in MG degradation. This study will provide new possible strategies for the remediation of wastewater contaminated by MG.

Guar gum, a low-cost sustainable biopolymer, for wastewater treatment: A review

Rapid population growth and the resultant pollution of freshwater resources have created a water stress condition reducing the availability of safe and affordable water. Guar gum, a biocompatible macromolecule obtained from the endosperm of the seeds of Cyamopsis tetragonolobus, is a fascinating raw material for multifunctional adsorbents. This review assembled the work conducted by various researchers over the past few decades and discussed the structure, properties, and different modifications methods employed to develop versatile guar gum-based adsorbent. The paper also summarized the recent progress of guar gum-based nanocomposites for the remediation of multiple hazardous substances such as organic dyes, toxic heavy metal ions, oil-water separation as well as inhibiting the growth of bacterial pathogens. Thus, the important contribution of guar gum composites to safeguard the water quality is highlighted which will overcome the limitations and streamline the future course of innovative research.

Soybean Replacement by Alternative Protein Sources in Pig Nutrition and Its Effect on Meat Quality

Soybean is one of the most expensive and limiting feed ingredients in diet formulations; however, in pig farming, it represents the main source of protein. The production and supply of soybean are critical steps due to their environmental impact and feed/food competition for land use. Therefore, research is focusing on finding alternatives to replace soybean partially or totally. However, alternative ingredients should ensure similar growth performance, carcass traits, and meat quality characteristics compared to conventional soybean-based diets. The objective of this review was to evaluate the impact of different alternative protein sources to soybean in pig nutrition and their effects on growth performance, carcass, and meat quality traits. The review process was performed on Scopus^®, and it considered research findings published from 2012 to the present on the Sus scrofa species. Articles without a control group fed with soybean were discarded. The main alternative protein sources identified were other legumes and distillers' dried grain with solubles (fish and animal proteins, oilseed by- and co-products). Interesting innovative protein sources included by-products from other industries (residues), microalgae and insects. Nevertheless, in dietary formulations, close attention must be paid to address the nutritional requirements, balance the supply of amino acids, avoid anti-nutritional or toxic compounds occasionally present in alternative protein sources, as well as determine the availability of protein feed in specific geographical areas.

Biowaste- and nature-derived (nano)materials: Biosynthesis, stability and environmental applications

Due to the environmental pollution issues and the supply of drinking/clean water, removal of both inorganic and organic (particularly dyes, nitroarenes, and heavy metals) to non-dangerous products and useful compounds are very important transformations. The deployment of sustainable and eco-friendly nanomaterials with exceptional structural and unique features such as high efficiency and stability/recyclability, high surface/volume ratio, low-cost production routes has become a priority; nonetheless, numerous significant challenges/restrictions still remained unresolved. The immobilization of green synthesized metal nanoparticles (NPs) on the natural materials and biowaste generated templates have been analyzed widely as a greener approach due to their environmentally friendly preparation methods, earth-abundance, cost-effectiveness with low energy consumption, biocompatibility, as well as adjustability in various cases of biomolecules as bioreducing agents. Natural and biowaste materials are widely considered as important sources to fabricate greener and biosynthesized types of metal, metal oxide, and metal sulfide nanomaterials using plant extracts. Integrating green synthesized nanoparticles with various biotemplates offers new practical composites for mitigating environmental challenges. In this review, degradation of dyes, reduction of toxic nitrophenols, absorption of heavy metals, and other hazardous/toxic environmental pollutants from contaminated water bodies using biowaste- and nature-derived nanomaterials are highlighted.

Guar gum based nanocomposites: Role in water purification through efficient removal of dyes and metal ions

Researchers nowadays are relentlessly on a race exploring sustainable materials and techniques for the sequestration of toxic dyes and metal ions from water bodies. Biopolymers such as guar gum, owing to its high abundance, low cost and non-toxicity, are potential candidates in this field. Plenty of hydroxyl groups in the polymer backbone enable guar gum to be functionalised or grafted in a versatile manner proving itself as an excellent starting substance for fabricating upgraded materials meant for diverse applications. This review offers a comprehensive coverage of the role of guar gum-based nanocomposites in removal of dyes and heavy metal ions from waste water through adsorption and photo-catalytic degradation. Isotherm and kinetics models, fabrication routes, characterisation techniques, swelling properties and reusability as well as adsorption and degradation mechanisms are outlined. A detailed analysis with convincing results suggests a good future perspective of implementation of these materials in real-time wastewater treatment technology.

Polysaccharide-Based Packaging Functionalized with Inorganic Nanoparticles for Food Preservation

Functionalization of polysaccharide-based packaging incorporating inorganic nanoparticles for food preservation is an active research area. This review summarizes the use of polysaccharide-based materials functionalized with inorganic nanoparticles (TiO2, ZnO, Ag, SiO2, Al2O3, Fe2O3, Zr, MgO, halloysite, and montmorillonite) to develop hybrid packaging for fruit, vegetables, meat (lamb, minced, pork, and poultry), mushrooms, cheese, eggs, and Ginkgo biloba seeds preservation. Their effects on quality parameters and shelf life are also discussed. In general, treated fruit, vegetables, mushrooms, and G. biloba seeds markedly increased their shelf life without significant changes in their sensory attributes, associated with a slowdown effect in the ripening process (respiration rate) due to the excellent gas exchange and barrier properties that effectively prevented dehydration, weight loss, enzymatic browning, microbial infections by spoilage and foodborne pathogenic bacteria, and mildew apparition in comparison with uncoated or polysaccharide-coated samples. Similarly, hybrid packaging showed protective effects to preserve meat products, cheese, and eggs by preventing microbial infections and lipid peroxidation, extending the food product’s shelf life without changes in their sensory attributes. According to the evidence, polysaccharide-hybrid packaging can preserve the quality parameters of different food products. However, further studies are needed to guarantee the safe implementation of these organic–inorganic packaging materials in the food industry.

A Highly Efficient Ag Nanoparticle-Immobilized Alginate-g-Polyacrylonitrile Hybrid Photocatalyst for the Degradation of Nitrophenols

Herein, we report PAN-g-Alg@Ag-based nanocatalysts synthesis via in situ oxidative free-radical polymerization of acrylonitrile (AN) using Alg@Ag nanoparticles (Alg@Ag NPs). Various analytical techniques, including FTIR, XRD, SEM, TEM, UV-Vis, and DSC, were employed to determine bonding interactions and chemical characteristics of the nanocatalyst. The optimized response surface methodology coupled central composite design (RSM-CCD) reaction conditions were a 35-min irradiation time in a 70-mg L-1 2,4-dinitrophenol (DNP) solution at pH of 4.68. Here, DNP degradation was 99.46% at a desirability of 1.00. The pseudo-first-order rate constant (K1) values were 0.047, 0.050, 0.054, 0.056, 0.059, and 0.064 min-1 with associated half-life (t1/2) values of 14.74, 13.86, 12.84, 12.38, 11.74, 10.82, and 10.04 min that corresponded to DNP concentrations of 10, 20, 30, 40, 50, 60, and 70 mg L-1, respectively, in the presence of PAN-g-Alg@Ag (0.03 g). The results indicate that the reaction followed the pseudo-first-order kinetic model with an R2 value of 0.99. The combined absorption properties of PAN and Alg@Ag NPs on copolymerization on the surface contributed more charge density to surface plasmon resonance (SPR) in a way to degrade more and more molecules of DNP together with preventing the recombination of electron and hole pairs within the photocatalytic process.

Ecofriendly Green Synthesis of the ZnO-Doped CuO@Alg Bionanocomposite for Efficient Oxidative Degradation of p-Nitrophenol

In the present study, ecofriendly green synthesized ZnO/CuO nanorods were prepared by using the stabilizing and reducing characteristics of the alginate biopolymer. The bionanocomposite (BNC) material was characterized by various sophisticated analytical tools such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, UV-visible spectroscopy, differential scanning calorimetry, and the Brunauer-Emmett-Teller (BET) method. The composition of ZnO/CuO@Alg BNC was found to be C (16.16 ± 0.42%), O (42.26 ± 1.87%), Cu (31.96 ± 1.05%), and Zn (9.62 ± 0.48%), which also supports the approximate 3:1 ratio of Cu2+ and Zn2+ taken as the precursor. The nanocrystalline spinel ferrite was found to have a BET specific surface area of 19.24 m2 g-1 with a total pore volume of 0.075 cm3 g-1 and 1.45 eV as the band gap energy (E g). Further, the material was applied for the photodegradation of p-nitrophenol (PNP) under the advanced oxidative process (AOP) under visible sunlight irradiation. The visible light radiation was used for the degradation of PNP under pH 2 conditions and resulted in 98.38% of the photocatalytic efficiency of the ZnO/CuO@Alg catalyst within 137 min of irradiation time. The photocatalytic reaction was best defined by the pseudo-first-order kinetics which involves the adsorption of the PNP molecule on the surface of the catalyst, thereby demineralizing it in the presence of advanced active •OH radicals. The values of rate constant for the pseudo-first-order model (k 1) were calculated as 0.013, 0.016, 0.019, 0.021, and 0.023 min-1 with half-life periods of 53.31, 43.31, 36.47, 33.00, and 30.13 min for 10-50 mg L-1 PNP concentrations. The presence of t-butyl alcohol decreases the photocatalytic efficiency, which suggests that the degradation of PNP was accomplished by the •OH oxidative radical.

Sonophotocatalytic Degradation of Malachite Green by Nanocrystalline Chitosan-Ascorbic Acid@NiFe2O4 Spinel Ferrite

Statistics show that more than 700 thousand tons of dye are produced annually across the globe. Around 10–20% of this is used in industrial processes such as printing and dyeing, while about 50% of the dye produced is discharged into the environment without proper physicochemical treatment. Even trace amounts of dye in water can reduce oxygen solubility and have carcinogenic, mutagenic, and toxic effects on aquatic organisms. Therefore, before dye-containing wastewater is discharged into the environment, it must be properly treated. The present study investigates the green synthesis of nickel ferrite NiFe2O4 (NIFE) spinel magnetic nanoparticles (MNPs) via chemical coprecipitation of a solution of Ni2+/Fe3+ in the presence of a biopolymer blend of chitosan (CT) and ascorbic acid (AS). The magnetic nanomaterial was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy–energy dispersive X-ray analysis (SEM-EDX), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), differential scanning calorimetry (DSC), and vibrating-sample magnetometry (VSM). The material was further explored as a catalyst for the photocatalytic degradation of malachite green (MG) under visible light irradiation coupled with ultrasonic waves. The combination of 90 min of visible solar light irradiation with 6.35 W·mL−1 ultrasonic power at pH 8 resulted in 99% of the photocatalytic efficiency of chitosan-ascorbic acid@NIFE (CTAS@NIFE) catalyst for 70 mg·L−1 MG. The quenching of the photocatalytic efficiency from 98% to 64% in the presence of isopropyl alcohol (IPA) suggested the involvement of hydroxy (•OH) radicals in the mineralization process of MG. The high regression coefficients (R2) of 0.99 for 35, 55, and 70 mg·L−1 MG indicated the sonophotocatalysis of MG by CTAS@NIFE was best defined by a pseudo first-order kinetic model. The mechanism involves the adsorption of MG on the catalyst surface in the first step and thereby mineralization of the MG by the generated hydroxyl radicals (•OH) under the influence of visible radiation coupled with 6.34 W·mL−1 ultrasonic power. In the present study the application of photodegradation process with sonochemistry results in 99% of MG mineralization without effecting the material structure unlike happens in the case adsorption process. So, the secondary pollution (generally happens in case of adsorption) can be avoided by reusing the spent material for another application instead of disposing it. Thus, the ecofriendly synthesis protocol, ease in design of experimentation like use of solar irradiation instead of electric power lamps, reusability and high efficiency of the material suggested the study to be potentially economical for industrial development at pilot scale towards wastewater remediation.