Preparing xanthan gum nanocomposite hydrogel and modified montmorillonite by tri-aminopropyltriethoxy

Abstract

This research indicates a new kind of bio-self-assembled nanocomposite hydrogel based on natural xanthan polymer and sodium montmorillonite nanoparticle in the field of polymers, which is modified by Triaminopropyl triethoxysilane. This process does not contain any chemical cross-linking agent and it also has been synthesized; this bio-self-assembled nanocomposite hydrogel aims to function as a removal of heavy metals from drinking water and wastewater because it has the property to absorb ions. The self-assembling hybrid nanocomposite hydrogel is composed of xanthan gum which is a natural polymer and sodium montmorillonite which is an unmodified clay nanoparticle with precursor triaminopropylene triethoxysilane and hydrolysis of the precursor to stabilize nanoparticles to increase the surface area absorbent matrix, abundant binding and absorption sites, improvement of swelling behavior; the increase of the absorption capacity of heavy metals in the absence of any crosslinking agent was designed and synthesized.

Description

Preparing Xanthan Gum Nanocomposite Hydrogel and Modified Montmorillonite by Tri-Aminopropyltriethoxy

[0001] In the present research, a new bio-self-assembled nanocomposite hydrogel based on natural xanthan polymer and sodium montmorillonite nanoparticle modified by Tri-aminopropyl triethoxysilane without using any chemical cross-linking agent was successfully synthesized and for the removal of heavy metals from drinking water, has been studied.

[0002] FTIR, SEM, XRD analysis were used to identify and describe the surface, structural, and mechanical properties and to study the absorption mechanism of the formed adsorbent. The effects of several parameters, including pH, contact time, initial ion concentration, and the effect of interfering ions, etc. on the amount of metal absorption will be investigated.

[0003] Experimental data will be analyzed using equilibrium and kinetic isotherm models such as pseudo-first-order, pseudo-second-order, intraparticle diffusion, Langmuir and Freundlich models, and thermodynamic studies for the absorption process. Finally, the reusability (several adsorption-desorption cycles using the desorption agent) will be studied as a hopeful economic attraction for practical and industrial applications. Therefore, with the help of the findings of this research, it can be shown that it is possible to remove heavy metals from drinking water with the help of biosynthetic nanocomposite.

[0004] In this research, the adsorption method by hydrogel is used due to the low price of the absorbent and the lack of secondary pollution in the treatment process. Therefore, the method is widely applied to remove heavy metal ions in wastewater and is considered one of the greenest and most promising methods.

[0005] A green process and method for the synthesis of smart all-biopolymer hydrogel for water and wastewater treatment:

[0006] With the growth of the urbanization population and the expansion of various industries such as casting, metal melting, plating, battery manufacturing, and even old urban plumbing, the possibility of the presence of various ionic pollutants in water and wastewater has increased due to the toxicity of heavy metals, the most common metals that Lead, mercury, arsenic, and cadmium play a more prominent role in poisoning human. Other heavy metals such as copper, zinc, and chromium are necessary for the body in very small amounts, but these elements can cause poisoning in large amounts.

[0007] Heavy metals are common byproducts in the metallurgy industry, mining, and other processes which can cause toxicity in pollutant surface water. The amount of the produced wastewater by industrial activities is full of tough and bioaccumulated poisonous heavy metals which are threats to the environment and human health Because heavy metals are very soluble in water and are no longer degradable. There is a connection between +Cd2+ ions and the food chain which accumulates in organs and tissues of the body. There are several crucial health consequences associated with Ni2+ and Cu2+ ions. The first can cause neurological and epidermic problems. While Cu2+ ions accumulation in the food chain leads to insomnia, liver damage, and Wilson disease.

[0008] World Health Organization (WHO) suggests that drinking water should not exceed 2-0.02 mg per liter of each. Therefore, pollutant wastewater must be treated to omit Cd2+. There are several ways to eliminate the discussed metallic ions, such as electrochemistry, membrane separation, chemical deposition, ion exchange, and absorption. To get rid of poisonous heavy metals, the second method is the most simple and affordable way.

[0009] Contamination of several adsorbents from various sources has been described in the literature, including activated carbon, minerals (such as zeolites), carbon nanotubes, biowastes, biopolymers, and metal-organic framework materials. However, few of these have all the characteristics that can turn them into ideal absorbers. The superior ability of biomaterials to absorb metal ions also makes them increasingly a raw material because of their biodegradability and biocompatibility. The use of biopolymers in various frameworks has become increasingly common in recent years. Adsorbents for heavy metals, among them, hydrogels, and hydrophilic polymers have a porous structure and light cross-links, which make them highly hydrated. Nowadays, most of the absorbents for the waste treatments of hydrogels derived from derived polymers are from non-renewable and non-degradable petroleum raw materials. Physical hydrogels are more cross-linked than chemical hydrogels.

[0010] The constituent molecules in physical hydrogels create a physically cross-linked polymer network through dynamic non-covalent interactions (such as electrostatic interactions or hydrogen bonds).

[0011] However, biopolymers suffer from problems such as weak mechanical properties and water solubility when being used as adsorbents, but with a suitable pair of biopolymers, they can be physically connected to form a composite.

[0012] C02F 103 / 38 - C02F 1 / 00

[0013] US11679995B2- Methods for preparing porous nanocomposite polymer hydrogel beads for water treatment

[0014] Synthesis, fabrication, and application of nanocomposite polymers in a different form (as membrane / filter coatings, as beads, or as porous sponges) for the removal of microorganisms, heavy metals, and organic, and inorganic chemicals from different contaminated water sources.

[0015] The used graphene oxide nanoparticle in this invention is not modified while the montmorillonite nanoparticles modified by triaminopropylene triethoxysilane are used in our invention, which expands the surface of the hydrogel and increases the functional groups on the surfaces, as a result of which the absorption of pollutants increases to a significant extent. Also, in this research, an acidic atmosphere was not used, but in our work, an acidic atmosphere was used as a simpler method without the need to monitor this parameter, which is the advantage of the method.

[0016] Also In this invention, the iron-crosslinked sodium alginate has been used, which is a secondary pollutant itself and after being damaged, it causes pollution in the environment. The acidic atmosphere is not used in this research but we used it as a simpler method without monitoring the parameter which is considered as an advantage of the method. This hydrogel is only for absorbing phosphate

[0017] US11305258B2 -Nanocomposite hydrogels and methods of using same in purifying a fluid

[0018] There is provided herein a method for preparing a graphene oxide (GO) hydrogel. The method comprises the steps of adding vitamin C (VC) to a dispersion GO in a ratio GO:VC varying from 1:50 to 1:300; and incubating at a temperature above 45° C., preferably at 95° C. The dispersion for a time sufficient for a porous hydrogel to be self-assembled from the dispersion. CNPs can also be added to the hydrogel in a ratio GO:CNPs from 4:1 to 1:1. There is also provided the hydrogel so obtained and its use for removing contaminants from a fluid. The hydrogel can also be used as a filter for such decontamination.

[0019] The unmodified graphene oxide is used in this research while we have used the modified graphene oxide nanoparticle and the result is increased surface and absorption as a result. Also, the selectivity of the synthesized hydrogel in our research is much higher than this hydrogel. In the presence of other competing ions, we see a better performance, and the mechanical properties are significantly increased, so that in 5 cycles of absorption and desorption, we see a small difference in absorption. The acidic atmosphere is not used in this research but we used it as a simpler method without monitoring the parameter which is considered as an advantage of the method.

[0020] 16 / 519163- Polymer nanocomposite-based composition and method for controlling water hardness

[0021] A nanocomposite composition for controlling water hardness and a method of producing the nanocomposite is disclosed. The nanocomposite composition comprises a plurality of semi-interpenetrating polymer network / zeolite-silver nanocomposite, including a polymer matrix. The polymer matrix is dispersed with a plurality of zeolite nanoparticles and a plurality of silver nanoparticles. The method of producing semi-interpenetrating polymer networks / zeolite-silver nanocomposite as hydrogel form comprises microemulsion polymerization of monomeric mixture uses methyl methacrylate (MMA) in presence of ethylene glycol dimethacrylate (EGDM) cross-linker for MMA monomer, acrylamide (AAm), acrylic acid (AAc) and linear polyvinyl alcohol (PVA) monomers in the presence of N, N′-methylene bis-acrylamide (MBA) cross-linker and TX-100 surfactant. Further, the prepared nanocomposite is a water hardness removal filter and an efficient inhibition of sulfate-reducing bacteria nanocomposite. Also, the water filter cartridge exhibits a stable filtration performance during large-scale production with reduced fluctuation infiltration flow rate and shows highly stable behaviors in high salt concentrations.

[0022] In this invention, Silver Nanoparticles are used that are much more expensive and are considered secondary pollutants. The nonbiological polymer has also been used in this hydrogel which causes lots of damage to the environment. The elimination mechanism in this system is the creation of a colloid but in our method, it happens by surface absorption and the creation of ion-electrostatic interactions.

[0023] IR 87274- creation of hydrogel with herbal combinations to separate the heavy metals from industrial and mine wastewater

[0024] Summary: Using the prepared adsorbents, it is possible to remove heavy metals (CTA1, CTA, CTA4) from aqueous TiO2 hydrogel. To make these adsorbents, Acrylamide and some commercial Nanoparticles have been used. Besides, its high absorption potential, it has unique features like being porous and nontoxic, recycling capability of the metal and polymer, heat resistance, and purification of a vast domain of density. Also, to create this polymer, sunlight was used instead of heat.

[0025] Difference: in this research, the third crosslinker factor was used and it is not in the form of self-assemble. Also, non-modified Nanoparticle was used for this case, while in our case, we have used modified Nanoparticles. Montmorillonite which is more viable in comparison to titanium oxide and has a shorter half-life in the environment was used.

[0026] IR 97260- Synthesis of Superabsorbent Hydrogel Nanocomposite of Acrylamide-Acrylic Acid and Zeolite

[0027] Summary: in this invention, the synthesis of superabsorbent hydrogel Nanocomposite of Acrylamide- Acrylic Acid and Zeolite with polymerization of free radical method in the presence of primer Ammonium persulfate and Methylene base acrylamide is analyzed. By adding Zeolite Nanoparticles up to 1 percent of the weight, the water absorption will be increased up to 40 percent, and more porosity will cause the integrated structure to be super absorbent. Analyzing the water absorption in this super adsorbent indicates that it has the absorption capability of 1000-1300 grams of distilled water which is comparable to similar commercial products. To design the tests, the detailed factorial method is used. The main goal of the synthesis of the superabsorbent is to make it convenient for all types of soils from loamy to sandy. The super absorbent is designed to determine the absorption rate and the capability of keeping the water in 5 different types of soils that are the result of combining (0,25,50,75,100) percent sand with loamy soil. According to the results in the first week after watering with hard urban water, the soil with 50% sand had better moisture keeping, which from the agricultural point of view (468 ppm), is highly important. Also in sandy soil, after 53 days (30 days after controlling the sample) the soil turns back to its first weight.

[0028] Difference: in this research, a superabsorbent hydrogel composite of acrylamide, acrylic acid, and zeolite has been used, synthesized via free radical solution polymerization in the presence of an ammonium persulfate initiator and methylene bis-acrylamide cross-linker however, our work does not require an initiator, a cross-linking agent or a network creator. The acidic atmosphere was not also used. Our work indicates selective performance properties in the presence of other competing ions, whereas the hydrogel synthesized in this research does not demonstrate selectivity.

[0029] This invention is a hydrogel made of Xanthan gum and modified Montmorillonite with Triaminopropylene triethoxysilane removes heavy toxic metal ions such as Cadmium, Nickel, and Copper, as well as Methylene Blue cationic dye from water. The hydrogel has high absorption capacity, selectivity, and reusability. It causes minimal harm to the environment and does not cause secondary pollution.

[0030] The hydrogel produced through this method is fully compatible with biological systems. It is a double-network hydrogel that has high mechanical strength and a long lifespan. The synthesis process is cost-effective and doesn't require specialized equipment. The hydrogel is capable of absorbing pollutants many times, its mass and volume, using electrostatic and ionic interactions without the need for a cross-linker. It also has a selective function in the presence of symbiotic ions, and its efficiency is favorable.

[0031] So far, this method of acidic atmosphere and xanthan gum biopolymer modified by triaminopropylene triethoxysilane nanocomposite synthesis has not been used to remove heavy metals from drinking water and wastewater.Solution of Problem

[0032] First, the amount of 0.4 grams of CaCl2 salt per 1:1 xanthan-chitosan ratio, which is the optimal amount of salt used with maximum swelling, has been weighed. Then, a certain amount of xanthan and chitooligosaccharides (chitosan with a polymerization degree of 20) is weighed following the ratio (2:1), and then each 0.1 gram of xanthan is dissolved in 9 ml of distilled water and placed on a stiller at a temperature of 50 degrees for about 20 minutes. After the complete dissolution of the oligo chitosan, the weighted chitosan was added to the above solution and placed on a stiller at a temperature of 50 degrees for 2 hours. Finally, 5 to 6 drops of acetic acid were added to a large glass beaker and We transferred the prepared solution (slurry) to a smaller container placed it inside the large container, and sealed the lid of the outer container well. We placed the system on the stiller at a temperature of 50 degrees for 4 hours. Finally, the prepared gel is removed from the container and dried with ethanol.

[0033] Through this research, we developed a process through which a blend of xanthan gum and chitosan in various combinations was gelated / physically cross-linked to prepare a series of all-biopolymer hydrogel biofilms using a facile and low-cost solution casting technique. This process required that both biopolymer molecules gradually interacted in the presence of a salt, calcium chloride, as a charge screening agent at a definite concentration to control the sol-gel transition. The optimum hydrogel biofilm based on the XG / CS complex was used for the characterization of the structure and evaluation of its capability to adsorb heavy metal ions. By FT-IR spectroscopy and equilibrium swelling (95.4 g / g) at pH 7, the XG / CS hydrogel biofilm was demonstrated to contain both components and to be cross-linked physically. It took approximately 75 min for the equilibrium of adsorption to take place, and the adsorption process of Cd2+, Cu2+, and Ni2+ was governed by the model of second-order adsorption kinetics. At pH = 6 and a temperature of 298 K, the best adsorption of Cd2+, Cu2+, and Ni2+ ions was observed. Cd2+, Cu2+, and Ni2+ equilibrium adsorption data were well matched by the Langmuir isotherm model for the XG / CS bio-adsorbent film, with the highest amounts of adsorption (qm) being 152.33 mg / g, 144.79 mg / g, and 139.71mg / g, respectively. By analyzing FTIR spectra and SEM images of XG / CS biofilm loaded with specific metal ions and taking into account data on adsorption kinetics, mechanisms of chelation and electrostatic are likely driving metal ion adsorption. The metal ions bind onto the XG / CS biofilm spontaneously (ΔG°= -2.84, -2.55, and -2.76 kJ / mol) and exothermically (ΔH° = -31.448, -25.198, and -29.282 kJ / mol) at 298 K for Cd2+, Cu2+, and Ni2+ ions, respectively. It was also notable that the biofilm was able to regenerate and enabled five consecutive cycles of metal ion adsorption and desorption below pH 2 at room temperature. According to these results, the XG / CS hydrogel biofilm is capable of serving as an adsorbent in the removal of heavy metal ions from water.Advantage Effects of Invention

[0034] 1. The hydrogel synthesized by this method is completely biocompatible.

[0035] 2. In addition to absorbing heavy metal, the synthesized hydrogel can absorb cationic pollutants such as cationic dyes and can have both applications at the same time.

[0036] 3. This hydrogel is a double network that has high mechanical strength and as a result, increases the life of the hydrogel.

[0037] 4. The synthesis method is low-cost and economical and does not require specialized and expensive equipment and devices.

[0038] 5. The ability to absorb pollutants many times the initial mass and volume of hydrogels.

[0039] 6. It uses two types of physical interaction, electrostatic and ionic, and does not need a cross-linker.

[0040] 7. In the presence of symbiotic ions, it has a selective function and its efficiency is favorable

[0041] 8. Absorption of three ions of cadmium, nickel, and copper, which is metal cadmium with biological resistance, remains in the body for years (half-life of 25 years) after being absorbed by the organism, which leads to various cancers. Nickel is used in the battery industry. Small amounts of nickel are needed by the body to produce red blood cells, however, in excessive amounts, it is toxic. Copper is an essential element for human life, but in high doses, it can cause anemia, liver and kidney damage, and stomach and intestinal irritation.Examples

[0042] The purpose of this study is to fabricate a series of double-network complex hydrogel in an acetic atmosphere all-biopolymer by gelating / physically crosslinking a blend of xanthan gum and chitosan in various combinations using a facile, low-cost solution casting technique. It eliminates toxic chemicals associated with gelation due to the physical crosslinking of both biopolymers. The optimized biofilm was then tested for its ability to remove Cd2+, Ni2+, and Cu2+ metal ions from the aqueous solution after being characterized by their structure. Several key parameters determined how aqueous solutions transformed into colloidal suspensions or gel coacervates, and the XG: CS hydrogel's weight ratio. The XG / CS biofilm adsorption of Cd2+, Cu2+, and Ni2+ in aqueous solution was investigated to estimate the effects of initial pH solution, adsorbent dose, contact time, initial metal ion concentration, and ionic strength in batch experiments. A highly pH-dependent adsorption process was observed for three metal ions, with maximum adsorption efficiency at pH 6.0. A maximum amount of Cd2+, Ni2+, and Cu2+ ions was absorbable with 50 mg of the adsorbent at pH 6.0 for an initial metal concentration of 50 mg / L and found to be 73.33, 83.61, and 134.14 mg / g, respectively. The kinetic experimental data reasonably fit with the pseudo-second-order model. An equilibrium isotherm analysis was conducted using the Langmuir and Freundlich models; however, the Langmuir model provided the best correlation. For Cd (II), Ni(II), and Cu (II) ions at 25°C, the maximum monolayer adsorption capacity was 251.06, 248.72, and 271.04 mg / g, respectively. Furthermore, the biofilm was capable of regenerating, allowing metal ions to adsorb and desorb for five consecutive cycles at a pH below 2. Therefore, the developed biodegradable biofilm offers the potential for remediation of specified metal ions.

[0043] In the current study, the process through which a combination of biopolymers xanthan gum and montmorillonite modified by triaminopropylene triethoxysilane (APTES) in different proportions was physically connected (gelation) in the atmosphere acid to prepare a composite film of xanthan gum polymer and modified nanoparticles using an easy and low-cost method of aqueous solution molding. This process requires that 2 grams of montmorillonite be first dispersed in 50 mL of distilled water in ultrasonication for 20 minutes Then 2 ml of triaminopropylene triethoxysilane is added to it and slurried under reflux for 24 hours at a temperature of 120 degrees Celsius. After 24 hours, we centrifuge the resulting solution in 5 steps and finally dry the resulting sediment, which is modified montmorillonite (A-MMT).

[0044] In the second step, we add 3 grams of modified montmorillonite to 1 gram of xanthan gum dissolved in 7 ml of distilled water, and in a water bath with a temperature of 45 degrees in an acidic atmosphere set at pH = 7 for 40 minutes until it is stilled. We move the composite into a Petri dish and put it in an oven at 50 degrees Celsius for 6 hours.

[0045] An optimized nano-composite based on the XG / A-MMT complex was used to identify the structure and evaluate its ability to absorb heavy metal ions. By FT-IR spectroscopic technique and equilibrium swelling measurement (95.4 g / g) at pH = 7, it was found that XG / CS hydrogel biofilm containing both components and physically connected (mainly through interactions) electrostatic).

[0046] It took approximately 90 min for adsorption equilibrium to occur, and the adsorption process of Cd 2+, Cu 2++, and Ni 2+ fit well with a pseudo-second-order kinetic model. The best absorption of Cd2+, Cu2++, and Ni2+ ions was observed at pH = 6 and a temperature of 298 K. The equilibrium adsorption data of Cd2+, Cu2++, and Ni2+ were well matched with the Langmuir isotherm model for XG / CS absorbent film, the maximum amount of absorption (qm) is 182.11 mg / g, 65 mg / g, and 80.37 mg / g.

[0047] By analyzing the FTIR spectrum and images, SEM of the XG / CS biofilm loaded with metal ions, and considering the data related to the adsorption kinetics, chelation, ion exchange, and electrostatic mechanisms are most likely involved in metal ion adsorption. Spontaneous and exothermic adsorption of metal ions on XG / CS biofilm (ΔG° = -2.84, -2.55, and -2.76 kJ / mol) and exothermic (ΔH° = -31.448, -25.198, and -29.282 kJ / mol) It is done for Cd2+, Cu2++ and Ni2+ ions.

[0048] It is also worth mentioning that the biofilm can regenerate and can be used in five consecutive cycles of metal ion absorption and removal at pH ≥2 at room temperature. According to these results, it can be used as an adsorbent in removing heavy metal ions from water.

[0049] Also, to determine the optimal amount of montmorillonite modified by triaminopropylene triethoxysilane (APTES), Taguchi's test design has been used, which is shown in the following table:

[0050] XRD patterns

[0051] (a) Time-dependent adsorption on XG / CS gel of Cd2+ (pH = 6, C0 = 50 mg / L), Ni2+ (pH = 6, C0 = 50 mg / L), and Cu2+ (pH = 6, C0 = 50 mg / L), T = 25oC, m / V = 0.5 g / L.

[0052] (b) Effect of solution pH on the percentage removal of the XG / CS biofilm (conditions: pH 2-6 for Cd2+, Ni2+, and Cu2+, 25 oC ).

[0053] (c) Effect of metal ion concentration on the percentage removal.

[0054] (d) Effect of biofilm dosage on the percentage removal of metal ions.

[0055] (e) Plot of ΔpH versus pH (determination of pHpzc)

[0056] Effect of initial concentration and contact time on the adsorption of Cd2+, Cu2+, and Ni2+ onto XG / CS blended nanocomposites.

[0057] (a) The pseudo-first-order, pseudo-second-order

[0058] (b) plots of Elovich and intra-particle diffusion models for the adsorption of the metal ions on the XG / A-MMT biofilm

[0059] (c and d) (T = 25oC, C0 = 50 mg / l and pH = 6)

[0060] SEM images showing the surface of XG, and XG / A-MMT biofilm

[0061] (1:1). SEM images of XG, CS, and XG / A-MMT biofilm (before and after metal ions adsorbed)

[0062] (a) Recycling of XG / A-MMT gel in the removal of 50 mg / L Cd (II), Ni (II), and Cu(II) (pH 6.0, m / V = 0.5 g / L, and T = 298 K).

[0063] (b) Cd (II), Ni(II), and Cu(II) adsorption by the XG / CS biofilm in the presence of coexisting metal ions (Conditions: dosage = 50 mg (0.5 g L-1 ), C0 = 50 mgL-1, pH = 6.0, T = 298 K, contact = 90 min).

[0064] illustrates the process of wastewater optimization.

[0065] This innovation is used in the removal of heavy metals from drinking water and wastewater treatment, as well as the selective absorption of heavy metal ions of cadmium, nickel, and copper.

Claims

This invention is a preparation of Xantan gum nanocomposite hydrogel and modified montmorillonite with Triaminopropylene triethoxysilane for separating poisonous heavy metals and also colors from aqueous solution, recycling examination and the feature of reusing the synthesis absorbent.According to the first claim, this absorbent used Montmorillonite nano particles to increase the absorbing capacity.According to the first claim, by using Triaminopropylene triethoxysilane, the Montmorillonite surface is filled of agents so these combinations are not together because of functional increasement.According to the first claim, referring to the used matersials in synthesizing this hydrogel and bio polymer, the synthesized Xantan gum hudrogel is biodegradative and will not produce any secondary polluions after it.According to the fourth claim, the appearance of this hydrogel is thin almost hyaloid attachments near to creamy colour.According to the first claim, modified and functionalized nano particles with Triaminopropylene triethoxysilane are used in the produced nano composite hydrogel.According to the sixth claim, Triaminopropylene triethoxysilane is used to increase the functional groups of Montmorillonite.

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