Preparation and performance of alginate/basil seed mucilage biocomposite for removal of eriochrome black T dye from aqueous solution

Structure, chemical modification, and functional applications of mucilage from Mimosa pudica seeds - A review

Mimosa pudica (MP) is an ornamental plant due to seismonastic movements that close leaves and fall petioles in response to touch, wind, light, heat, cold, and vibration. The seeds of MP secrete smart, biocompatible, and non-toxic mucilage that has captivated researchers due to its widespread use in various fields such as pharmaceuticals and biotechnology. The mucilage is responsive to pH, salt solutions, and solvents and acts as a binder in tablet formulations for targeted drug delivery. The mucilage is chemically modifiable via acetylation, succinylation, and graft polymerization. Chemically modified MP mucilage appeared supersorbent for heavy metal ion uptake. Nanoparticles synthesized using mucilage as a reducing and capping agent displayed significant antimicrobial and wound-healing potential. Crosslinking of mucilage using citric acid as a crosslinking agent offers a sustained release of drugs. The present review is aimed to discuss extraction optimization, structure, modification, and the stimuli-responsive nature of mucilage. The review article will cover the potential of mucilage as emulsifying, suspending, bio-adhesive, gelling, and thickening agent. The role of mucilage as a capping and reducing agent for nanoparticles will also be discussed.

Development of basil seed mucilage (a heteropolysaccharide) - Polyvinyl alcohol biopolymers incorporating zinc oxide nanoparticles

The effect of zinc oxide nanoparticles (ZnONPs) on various properties of basil seed mucilage (a heteropolysaccharide)-polyvinyl alcohol (BSM-PVA) films was investigated. Increasing concentration of ZnONPs in BSM-PVA films reduced moisture content (from 24.73 to 17.09 %), water solubility (from 36.36 to 27.65 %), water vapor permeability (from 4.66 × 10-7 to 2.55 × 10-7 g·m/m2·Pa·h), oxygen permeability (from 2.96 to 2.13 cm3 μm/m2 d kPa), and elongation at break (from 40.34 to 29.44 %), and increased ultimate tensile strength (from 16.81 to 21.48 MPa). Color and light transmission were affected by ZnONPs concentrations. The lack of formation of new peaks, along with the displacement of peaks, indicated the formation of hydrogen bonds between ZnONPs and the film matrix. Dynamic mechanical-thermal analysis showed that storage modulus and glass transition temperature increased with the concentration of ZnONPs. Scanning electron microscopy images illustrated that the addition of ZnONPs improved film integrity. X-ray diffraction pattern showed that the crystal shape of nanoparticles was preserved in the film matrix. Films containing ZnONPs showed good antibacterial activity against Staphylococcus aureus (reductions ≥ 3 log CFU/cm2) and Escherichia coli (reductions ≥ 4 log CFU/cm2). Films containing ZnONPs also showed a suitable antifungal activity during the storage of wheat bread.

Process optimization for spray dried Aegle marmelos fruit nanomucilage: Characterization, functional properties, and in vitro antibiofilm activity against food pathogenic microorganisms

Recently, mucilage extraction from plant sources has been remarkably explored due to its potential applications. Several underutilized fruits such as Aegle marmelos are the potential source of mucilage that can be utilized for agri-food-pharma applications. Therefore, in this study, we explored vital functional and antimicrobial properties of Aegle marmelos nanomucilage. Spray drying conditions such as inlet temperature, feed flow, and atomization speed were optimized to assess the influence on yield and moisture content using response surface methodology. In addition, during the optimized spray drying conditions, the maximum mucilage yield was 16.23 % (w/w). The particle size (178.4 ± 5.06 nm) at the nanoscale, polydispersity index (0.432), and zeta potential (-16.4 ± 1.14 mV) confirmed the stability of the nanomucilage. Moreover, the spray-dried nanomucilage powder exhibited high thermal stability (55.70 J) and excellent industrially important techno-functional properties with water-holding capacity (8.01 ± 0.04 g/g), oil-holding capacity (3.43 ± 0.7 g/g), emulsifying capacity (91.50 ± 0.78 %), emulsifying stability (92.65 ± 0.46 %), solubility (89.36 ± 1.69 %), and foaming capacity (16.13 ± 0.41 %). Moreover, the powder showed strong antibiofilm activity against food-pathogenic bacteria, including Escherichia coli (73.52 ± 1.14 %) and Staphylococcus aureus (79.57 ± 1.23 %), with minimum inhibitory concentrations of 3.125 mg/mL and 1.562 mg/mL respectively. Overall, based on the above findings the spray-dried powder of Aegle marmelos fruit nanomucilage could be utilized as a potential functional ingredient in various food products formulations.

Super-efficient removal and adsorption mechanism of anionic dyes from water by magnetic amino acid-functionalized diatomite/yttrium alginate hybrid beads as an eco-friendly composite

The development of eco-friendly, large-capacity and easy-to-separate adsorbent materials has always been the focus and difficulty of adsorption technology in wastewater treatment applications based on the characteristics of dye wastewater. Therefore, in this study, a green magnetic glycine(Gly)-functionalized diatomite(Dia)/yttrium alginate (Y-SA) hybrid bead composite (Dia-Gly-Y-SA@Fe₃O₄) was synthesized by the droplet polymerization, and characterized by various modern analytical techniques. The adsorption performance and adsorption mechanism of the composite were evaluated and elucidated by the removal of anionic dyes direct Blue 106 (DB 106), Congo red (CR) and direct red 13 (DR 13) from water. The results show that the composite is a macroparticle gelpolymer with an average particle size of about 1.5 mm, flower-like fold surface structure, abundant porosity and sensitive magnetic response, and displays ultrastrong adsorption ability for three dyes. The adsorption equilibrium of each dye can be reached quickly within 30 min, and the removal efficiency is more than 95% at pH 2.0 and decreases slightly with pH up to 9.0. The adsorption processes could be explained by the Pseudo-second-order rate equation well. All isotherm data fitted the Langmuir model well, and the maximum adsorption capacities were 1635, 2359 and 1165 mg/g for DB 106, CR and DR 13 at 298 K, respectively. The ultrastrong adsorption performance was due to the multisite interaction of physicochemical action and various hydrogen bonds between hybrid beads and dye anions. As a cost-effective magnetic macroparticle adsorbent prepared by natural ingredients, Dia-Gly-Y-SA@Fe₃O₄ composite exhibits much more stronger adsorption efficiency, better collectability and no secondary pollution than powder Dia, and would have a good application prospect for the purification of anionic dye wastewater with a wide pH range.

Application of calcium alginate-PANI@sawdust wood hydrogel bio-beads for the removal of orange G dye from aqueous solution

This work aims to investigate the adsorption performance of orange G (OG) dye from aqueous solutions employing PANI@sawdust biocomposite enrobed by calcium-alginate bio-beads (Alg-PANI@SD). The as-prepared adsorbent was characterized by scanning-electron-microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), and Fourier transforms infrared (FT-IR) spectroscopy and used to remove orange G dye from aqueous water. Batch tests were performed as a function of adsorbent dosage, pH, contact time, interfering ions, and initial OG dye concentration. Experimental results show that the kinetic model of pseudo-first-order (PFO) and Freundlich isotherm perfectly fit the entire experimental data. Additionally, the prepared composite exhibited an excellent regeneration capacity and reusability for OG dye removal. The results revealed that the as-prepared Alg-PANI@SD bio-beads have the potential to be applied as a low-cost adsorbent for the adsorption of OG dye from aqueous media.

Fabrication of polyamide-12/cement nanocomposite and its testing for different dyes removal from aqueous solution: characterization, adsorption, and regeneration studies

Polyamide-12/Portland cement nanocomposite was prepared by using the exfoliated adsorption method. The fabricated nanocomposite was applied first time to remove Congo red (CR), brilliant green (BG), methylene blue (MB), and methyl red (MR) from the synthetic wastewater. The polymer nanocomposite was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, Brunauer-Emmett-Teller surface area analysis, and X-ray diffraction. The adsorption was rapid and all the studied dyes were absorbed on the surface of the polymer nanocomposite in 90 min. The point of zero charge was found at pH 5 and the factors such as pH, time, and temperature were found to affect the adsorption efficiency. Freundlich isotherm and pseudo-second-order models well-fitted the adsorption isotherm and kinetics data, respectively. The calculated maximum adsorption capacity was 161.63, 148.54, 200.40, and 146.41 mg/g for CR, BG, MB, and MR, respectively. The mode of the adsorption process was endothermic, spontaneous, and physical involving electrostatic attraction. On an industrial scale, the high percentage of desorption and slow decrease in the percentage of adsorption after every five regeneration cycles confirm the potential, practicality, and durability of the nanocomposite as a promising and advanced adsorbent for decolorization of colored wastewater.

Green Fabrication of Nonenzymatic Glucose Sensor Using Multi-Walled Carbon Nanotubes Decorated with Copper (II) Oxide Nanoparticles for Tear Fluid Analysis

In this report, a green, simple, inexpensive, and effective nonenzymatic electrochemical glucose sensor was fabricated using multi-walled carbon nanotubes (MWCNT) decorated with copper (II) oxide nanoparticles (CuO NPs). Basil seed mucilage (BSM) was served as reducing, capping, and stabilizing agents in the synthesis of CuO NPs.The prepared MWCNT/CuO nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and electrochemical methods. The FTIR results indicated that the nanocomposite surface was covered by BSM. The FESEM results show that the CuO NPs with an average particle size lower than 10 nm have been well distributed on the walls of the MWCNT. The electrochemical behavior of the nanocomposite was explored by studying the electrocatalytic behavior of the screen-printed carbon electrode (SPCE) modified by the nanocomposite (SPCE-MWCNT/CuO) toward the glucose oxidation. In the optimum conditions, the electrode indicated a wide linear response from 5.0 to 620.0 μM with regression coefficients of 0.992, the sensitivity of 1050 μA mM^-1 cm^-2, a limit of detection (LOD) of 1.7 μM, and a reproducibility with relative standard deviation (RSD) variations from 3.5 to 11% for three measurements at each point. The obtained results also showed good selectivity to glucose against interfering species such as lactate (LA), L-ascorbic acid (AA), and urea (U) due to the use of the negatively charged BSM in the form of a coating on the nanocomposite surface. The applicability of the sensor was successfully verified by the determination of glucose concentration in artificial tears with a certain amount of glucose.

Multi-Responsive Optimization of Novel pH-Sensitive Hydrogel Beads Based on Basil Seed Mucilage, Alginate, and Magnetic Particles

Conventional drug delivery systems often cause side effects and gastric degradation. Novel drug delivery systems must be developed to decrease side effects and increase the efficacy of drug delivery. This research aimed to fabricate hydrogel beads for use as a drug delivery system based on basil seed mucilage (BSM), sodium alginate (SA), and magnetic particles (MPs). The Taguchi method and Grey relational analysis were used for the design and optimization of the hydrogel beads. Three factors, including BSM, SA, and MPs at four levels were designed by L-16 orthogonal arrays. BSM was the main factor influencing bead swelling, drug release rate at pH 7.4, and release of antioxidants at pH 1.2 and 7.4. In addition, SA and MPs mainly affected drug loading and drug release rate in acidic medium, respectively. Grey relational analysis indicated that the composition providing optimal overall properties was 0.2 vol% BSM, 0.8 vol% SA, and 2.25 vol% MPs. Based on the findings of this work, BSM/SA/MPs hydrogel beads have the potential to be used as a pH-sensitive alternative material for drug delivery in colon-specific systems.

Biobased composites from agro-industrial wastes and by-products

The greater awareness of non-renewable natural resources preservation needs has led to the development of more ecological high-performance polymeric materials with new functionalities. In this regard, biobased composites are considered interesting options, especially those obtained from agro-industrial wastes and by-products. These are low-cost raw materials derived from renewable sources, which are mostly biodegradable and would otherwise typically be discarded. In this review, recent and innovative academic studies on composites obtained from biopolymers, natural fillers and active agents, as well as green-synthesized nanoparticles are presented. An in-depth discussion of biobased composites structures, properties, manufacture, and life-cycle assessment (LCA) is provided along with a wide up-to-date overview of the most recent works in the field with appropriate references. Potential uses of biobased composites from agri-food residues such as active and intelligent food packaging, agricultural inputs, tissue engineering, among others are described, considering that the specific characteristics of these materials should match the proposed application.

Modified wheat straw-derived graphene for the removal of Eriochrome Black T: characterization, isotherm, and kinetic studies

A cost-effective and environment-benign adsorbent was prepared from an abundant agro-waste material. Wheat straw was reduced to graphene and then modified by crosslinking to epichlorohydrin. During the conversion process of wheat straw to graphene, the specific surface area increased more than 100 times (from 4 to 415 m² g^-1). The adsorption efficiency of raw wheat straw, graphene nanosheets, and modified graphene against Eriochrome Black T (EBT) were 8.0, 34.7, and 74.4%, respectively. The modified graphene was further investigated for the effect of environmental condition, i.e., pH (3 to 11), EBT concentration (25-100 mg L^-1), adsorbent dosage (0.25-0.75 g L^-1), contact time (5-60 min), and solution temperature (30-60 °C). The dye removal remained at a high level under a wide range of pH from 3 to 9. The EBT removal decreased from 87.3 to 54.5 by increasing dye concentration and increased from 38.2 to 85.4% by increasing adsorbent dose in the studied ranges. Dye removal also increased by mixing time from 5 to 30 min, whereas a slight drop was observed by continuing agitation up to 60 min. Conducting experiments at various temperatures revealed an endothermic process. Pseudo-first-order and pseudo-second-order models were adequate to represent the adsorption kinetics. Isotherm models suggest a multilayer adsorption of EBT molecules on heterogeneous modified graphene surface with a maximum adsorption capacity of 146.2 mg g^-1. The present work demonstrated that the modified graphene obtained from available and low-cost agro-wastes could be used effectively as adsorbent against EBT from aqueous media.

Fabrication of Zn-based magnetic zeolitic imidazolate framework bionanocomposite using basil seed mucilage for removal of azo cationic and anionic dyes from aqueous solution

The Basil seeds mucilaginous polysaccharide exhibits remarkable physical and chemical properties like high water-absorbing capacity, emulsifying, and stabilizing properties. The metal-organic frameworks are one of the most promising precursors made of metal clusters and organic connectors for the fabrication of advanced adsorbents due to their unique properties. In this study, the bionanocomposite of magnetic zeolitic imidazolate framework-8 was successfully synthesized and applied to adsorb azo cationic and anionic dyes. The synthesized magnetite nanoparticles were pretreated with mucilage extracted from basil seeds to acquire negatively charged magnetite surface, followed by nucleation through attracting zinc cation, and then the growth of metal-organic frameworks which yields high-quality ZIF-8 crystals. The samples were characterized by Field Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared Spectrometry, vibrating sample magnetometer, and Brunauer-Emmett-Teller surface area analysis. In the process of adsorption, influencing factors and recycling regeneration were discussed, and the adsorption mechanisms such as kinetics, isotherm, and thermodynamics were explored. The results of the adsorption process showed that maximum adsorption capacities were 9.09 and 13.21 mg/g for Methylene blue and Eriochrome Black T, respectively. The excellent reusability combined with its magnetic separation property makes the nanocomposite a promising adsorbent for the removal of cationic and anionic dyes.

Elucidation of fungal dye-decolourizing peroxidase (DyP) and ligninolytic enzyme activities in decolourization and mineralization of azo dyes

AIM

The aim of the study is to investigate the efficiency of Geotrichum candidum in the decolourization and mineralization of synthetic azo dyes.

METHODS AND RESULTS

It includes screening of enzymes from G. candidum and its optimization, followed by decolourization and mineralization studies. Decolourization was observed to be maximum in methyl orange (94·6%) followed by Congo red (85%), trypan blue (70·4%) and Eriochrome Black T (55·6%) in 48 h, suggesting the plausible degradation of the azo dyes by G. candidum. The enzyme activity study showed that DyP-type peroxidase has highest activity of 900 mU ml^-1 compared to that of laccase (405 mU ml^-1 ) and lignin peroxidase (LiP) (324 mU ml^-1 ) at optimized pH (6) and temperature (35°C). Moreover, the rate of decolourization was found to be directly proportional to the production of laccase and LiP, unlike DyP-type peroxidase. Furthermore, mineralization study demonstrated reduction in aromatic amines, showing 20% mineralization of methyl orange.

CONCLUSION

Geotrichum candidum with its enzyme system is able to efficiently decolourize and mineralize the experimental azo dyes.

SIGNIFICANCE AND IMPACT OF THE STUDY

The efficient decolourization and mineralization of azo dyes makes G. candidum a promising alternative in the treatment of textile effluent contaminated with azo dyes.