HYBRID BIOCHAR INFUSED POLYMER MEMBRANE DERIVED FROM AGRO-BASED WASTE PEELS FOR DYE ADSORPTION

Abstract

Title: "Hybrid biochar infused polymer membrane derived from agro-based waste peels for dye adsorption" The discharge of dye effluent from the industry is a severe threat to the environment and the ecosystem. The dye effluent has to be treated before discharging. The treatment methods such as filtration, carbon adsorption, photo catalytic degradation and oxidation are employed in industries. In this regard, the invention presents a method for preparing biochar from waste onion and garlic peels through pyrolysis process at different activating conditions. Pyrolysis under acidic and alkaline conditions using phosphoric acid and sodium hydroxide respectively at 400°C yields activated biochar. Then, the polymer membrane is fabricated using a polyvinyl alcohol solution by incorporating biochar to enhance the adsorption properties. The membrane's dye adsorption capacity is tested for methylene blue and congo red synthetic dye at a concentration of 50 ppm. The effect of pH in adsorption is studied by varying from 3 to II. This method suggests an eco­ friendly approach for agro-waste valorisation and the development of efficient materials for dye removal in wastewater treatment.

Specification

Title: Hybrid biochar infused polymer membrane derived from agro-based waste peels for dye adsorption
Field of the Invention: The present invention relates to the field of waste utilisation and waste management, specifically the fabrication of polymer membrane from the agriculture-based waste peels biochar. The agro-based waste material includes rice husk, wheat straw, sugarcane bagasse, seedpods, potato peels, coconut shells, onion peels, garlic peels, etc. In this invention, the onion and garlic peels are treated in muffle furnace under closed condition for the production of biochar. The biochar from the waste peels are activated at varying temperatures (200 °C, 400 °C and 600 °C) and varying pH (acidic and alkaline) as well. The obtained biochar is infused in the polymer membrane to determine the effect of dye adsorption. The synthetic anionic and cationic dyes are used for the study. The membranes are prepared by varying the weight percentage of cross-linking agent by 7.5%, 15% and 22.5% and its stability is assessed by means of solubility test. The dye adsorption capacity of the membranes is characterized using UV-visible spectroscopy. The present invention emphasizes the use of waste peel biochar within polymer membranes as an innovative method for dye treatment. This technique offers a viable alternative to conventional river sand filtration, facilitating dye adsorption. The key features of this development address the challenges of agricultural waste management while exploring the synergy between sustainable practices and dye treatment, highlighting the environmental effects.
Background of the Invention:
Agricultural waste is a left over from the agricultural operation in the process of crop growing and animal raising. Moreover, the agro-based wastes are treated in a sustainable method for the betterment of quality improvements in
air, soil and water sources by sustainable methods include pyrolysis under absence of oxygen for char production at high temperature, compost, fertilizer production and methane gas production. Here, the char production from waste materials promotes research opportunities for various applications. Likewise, polymer membrane fabrication finds its applications in different areas, and also in the field of water and wastewater treatment.
An approach towards the utilisation of activated carbon from waste agrobased materials into the aqueous polymer and a cross-linker finds its potential in the fields of synthetic dye treatment as an adsorbent material. Conventional dye adsorption methods often rely on synthetic adsorbents, which can pose environmental challenges. This invention aims to utilize biochar, derived from agro-based waste peels, as a sustainable and effective material for dye removal. The innovative approach towards the preparation of polymer membranes incorporating hybrid biochar enhances dye adsorption capacity, offering an eco-friendly solution for dye effluents.
Objectives
The primary objective of the invention is to develop a methodology for producing biochar from agro-based waste peels, such as onion and garlic, using pyrolysis under controlled conditions. This involves characterizing the synthesized biochar to assess its suitability for dye adsorption based on the surface area. In this regard, the polymer membranes are infused by 5wt% of the biochar to study the effect of dye adsorption capacity. The effectiveness of these membranes will be evaluated using the synthetic anionic and cationic dyes under different operating conditions.
Brief description of prior art
CN110302756B (2022) discloses the invention relates to the method for removing heavy metal ions by using industrial waste residue
modified biochar, which specifically comprises the following steps of (1) pre-treating raw materials; (2) activating industrial waste residues; (3) mixing the activated industrial waste residue with the treated organic waste; (4) pyrolyzing the uniformly mixed sample; (5) removing heavy metals in the water solution polluted by the heavy metals by the pyrolysis residues; (6) analysing the heavy metal ions, calculating the removal rate and the like. According to the invention, cheap industrial waste residues are used as a heat transfer carrier and an activating agent, in the formation process of the biochar, the polymerization degree of aromatic hydrocarbon in the biochar is improved, the physical and chemical microstructures of the biochar are improved, pollution components in the industrial waste residues are fixed in the pyrolysis process, the alkalinity is reduced, and the energy and material utilization of organic wastes and the harmless and resource utilization of the industrial waste residues are realized.
US11214528B2 (2022) discloses the invention relates to the method and system provided for water treatment to remove contaminants using treated biochar placed in the water flow pathway of a water treatment process. The system further includes the further treatment of the treated biochar after its use in the water treatment process for use in agricultural or animal applications.
CN114272859A (2022) discloses the invention relates to the system comprises a carbonaceous material pyrolysis unit (I), a pyrolysis gas chemical conversion unit (2), a catalyst gas-solid separation unit (3), a catalyst regeneration unit (4) and a flue gas purification and waste heat recovery unit (5), which are sequentially connected. A high-temperature pyrolysis reaction of the carbonaceous material coal or biomass takes place in the carbonaceous material pyrolysis unit (1); the chemical conversion of tar occurs in the pyrolysis gas chemical conversion unit (2) to obtain micro molecule compounds CO and H2, NfhAnd/or lower hydrocarbons; the
catalyst gas-solid separation unit (3) separates the micromolecular compound gas from the catalyst; the burning reaction of carbon deposition on the catalyst occurs in the catalyst regeneration unit (4), and the regeneration is obtained. The invention couples the pyrolysis of the carbonaceous material with the direct conversion of the pyrolysis gas, and solves the problems of difficult treatment of phenolic wastewater and high-temperature hot gas in the existing coke and semi coke production and biomass pyrolysis processes heat energy loss, equipment blockage and the like.
CN108579676B (2020) discloses the invention relates to the preparation method of a recyclable biochar composite material, which belongs to the technical field of new materials, and the recyclable biochar composite material is prepared by taking organic waste biomass subjected to activation pre-treatment as a raw material and loading metal and metal oxide particles on the porous biochar material through a series of treatment processes.
CN112973632A (2021) discloses the invention relates to the technical field of solid waste utilization and environmental pollution treatment, and particularly relates to biochar modified based on an alkaline solution, a preparation method and application thereof. The invention adopts cheap jujube charcoal as raw material, and can utilize biomass waste in a high-value way and bring certain environmental benefit by modifying the jujube charcoal and using the jujube charcoal for treating printing and dyeing sewage. The preparation method is simple, the modification condition is mild and easy to realize, and the modified jujube wood biomass charcoal can effectively adsorb dyes in water and reduce the chromaticity of sewage when being applied to printing and dyeing sewage treatment.
US10071335B2 (2018) discloses the invention relates to the ozonized biochar compositions and methods for creating advanced hydrophilic biochar materials are provided with higher cation exchange capacity, optimized pH, improved wettability, and free of potential toxic components. These ozonized
biochar compositions are used as filtration materials, as biochar soil additives and as carbon sequestration agents to help control climate change for energy and environmental sustainability on Earth.
US7189322B2 (2007) discloses the invention of a hydrophilic charged microporous membrane comprising a porous hydrophobic substrate and a coating comprising a charge-providing agent. The present invention further provides a hydrophilic charged membrane comprising a porous hydrophobic substrate and a hydrophilic charge-providing agent distributed within the substrate. The present invention further provides a filter as well as a filter device comprising the inventive hydrophilic charged membrane. The present invention further provides a process for treating a fluid containing bacterial contaminants such as endotoxins comprising contacting the membrane with the fluid to provide a bacterial contaminant depleted fluid.
KR101136943B1 (2020) discloses the invention relates to a method for producing a hydrophilic membrane having improved fouling resistance using a supercritical fluid or a subcritical fluid, and more particularly, after introducing a monomer, an initiator and a crosslinking agent containing a hydrophilic group into a high pressure solution container, Preparing a coating solution by introducing and dissolving a critical fluid; Fixing the separator to an internal heater in the high pressure coating vessel and pressurizing the pressure of the high pressure coating vessel to be equal to that of the high pressure solution vessel, and then transferring the coating material from the high pressure solution vessel to the high pressure coating vessel to contact the separator; Coating monomers, initiators and crosslinking agents contacted with the separator in step 2 on the surface and micropores of the separator through a crosslinking reaction and a polymerization reaction; Lowering the temperature of the internal heater in the high pressure coating vessel and transferring the unreacted coating material back to the high pressure solution vessel; And lowering the pressure of the high pressure
coating vessel to atmospheric pressure, recovering the prepared hydrophilized membrane, and then washing and drying the hydrophilic membrane using the supercritical fluid or the subcritical fluid. According to the present invention, the separator prepared according to the present invention has excellent thermal safety, chemical stability, and mechanical strength, which are the properties of hydrophobic separators, and the surface and the pores of the separator are made of a hydrophilic material by using a crosslinking reaction. Since it is uniformly coated, the amount of permeated water is high and protein adsorption is low.
CN109173746B (2021) discloses the process for preparation of a composite membrane for efficiently filtering micro-pollutants in water. The method comprises the following steps: the functional beta-cyclodextrin is used as a film-making additive, and is dissolved in a solvent with a film-forming polymer, a pore-forming agent and a cross-linking agent according to a set proportion to prepare a film-casting solution, and the composite film capable of efficiently filtering organic micro-pollutants is prepared by moderate in-situ cross-linking of the functional beta-cyclodextrin in the film-casting solution and adopting an immersion precipitation phase conversion method. The composite membrane has high water permeability and high removal rate of micro-pollutants in water. The composite membrane not only can filter and remove pollutants such as plankton, algae, bacteria, protein, colloid, virus and the like, but also can absorb and remove organic micromolecular micropollutants such as antibiotics, hormones, plasticizers and the like. The preparation process of the composite membrane is simple and controllable, has low cost, can be widely applied to the separation fields of household water purification, sewage treatment, water quality purification and the like, is an efficient and stable water treatment material, and has wide application value.
US11345615B2 (2022) discloses the invention relates to the activated carbon, e.g., from waste tires, modified by bimetallic Fe and Ce nano particles can provide high surface area and active sites for enhanced dye adsorption. Such nanocomposites can offer magnetic removal from aqueous solutions containing, e.g., Methylene Blue or Rhoda mine B. Adsorption equilibrium data fit well to the Langmuir isotherm model, with an adsorption capacity was 324.6 mg/g. Rhodamine B adsorption by such activated carbon-Fe-Ce magnetic adsorbents has an endothermic character and pseudo-second-order kinetics. In ethanol solution, rhodamine B was desorbed at high efficiency and such materials, which could be recycled up to 5 cycles. Such magnetic nauocomposites are adsorbents for treating dyes such as rhodamine B in wastewater, even in large scale adsorption systems. Polyamides can be grafted to such nanocomposites.
US10351455B2 (2019) discloses the embodiments of a system for treating water. The system comprises a biochar inlet, and optionally a metal salt inlet, ozone inlet, organic carbon compound inlet or any combination thereof. The biochar may be produced by biomass pyrolysis and the pyrolysis may be coupled to energy generation. The system also comprises a filtration device, such as a reactive filtration device. The system produces a treated water stream and a reject stream, which may be further separated into a recycled water stream and a solid product. The solid product may be suitable as a soil amendment for application to agricultural land, or for recycling. A method for using the system to treat water also is disclosed.
CN104355487A (2015) discloses the invention relates to the technical field of sewage treatment and environment protection, and in particular relates to an ecological sewage treatment method which comprises the following steps: I, performing chemical carbon sequestration treatment on sewage, namely, feeding a chemical agent polymeric aluminum, polymerization ferric chloride, aluminum sulfate or polyacrylamide into sewage to be treated
firstly; II, performing ultrasonic synergic aeration biological treatment on the sewage after chemical carbon sequestration treatment in a biological treating pond; and III, performing ecological sewage treatment, namely, discharging the sewage subjected to the ultrasonic synergic aeration biological treatment in the biological treating pond into a wetland ecosystem facility. The ecological sewage treatment method provided by the invention has the advantages that firstly, low carbon is realized, and secondly, the operation mode is flexible.
Summary of the invention
The present invention relates to the development of biochar towards dye adsorption for different dyes. The acid activated, alkali activated and unactivated biochar was prepared by pyrolyzing the onion and garlic peels at varied temperatures viz., 200°C, 400°C and 600°C, respectively. The surface area of unactivated, alkali activated and acid activated biochar from onion peels are 11.1 m2/g, 21.3 m2/g and 80.6 m2/g respectively. Similarly, for garlic peels, the surface area are 47.6 m2/g, 48.6 m2/g and 98.3 m2/g respectively. The developed membranes were made of 5wt% of mono and hybrid biochar. In the case of varying temperature, as the temperature increases, the stability of biochar also increased.
Detailed description of the invention
Example 1: Preparation of biochar
The present invention involves the preparation of biochar from waste discarded onion and garlic peels through a series of processes, including drying, pyrolysis, and grinding. The samples are dried in hot air oven at a temperature of 45°C for two days to remove the moisture content present in it. The difference in weight between the initial and hot air oven treated samples provides the percentage moisture content in the sample. The dried sample peels are powdered using a mixer grinder, and subjected to the
pyrolysis operation. The samples are treated under acidic and alkaline conditions for the activation of the synthesized carbon form i.e., biochar. For acidic activation, the phosphoric acid (H3PO4) is added to the powdered samples at a ratio of 1:5. Similarly, sodium hydroxide (NaOH) is added to the samples for the same weight ratio of 1:5 for alkaline activation. The samples under acidic, alkaline and unactivated are subjected to hydrolysis in a muffle furnace at temperature of 200°C, 400°C and 600°C for the duration of 3 hours. The muffle treated samples are soaked in distilled water to study the solubility of the synthesized biochar. From the observation, the sample pyrolyzed at 200°C is soluble in distilled water where the samples pyrolysed at 400°C and 600°C are insoluble. Thus, the optimum temperature for the process is chosen as 400°C. Biochar obtained from the above mentioned process is washed multiple times in distilled water for removing the impurities and dried in hot air oven at temperature of 100°C.
Example 2: Preparation of polymer membrane
For membrane fabrication, 10% aqueous Polyvinyl alcohol (PVA) is used throughout experimentation, and the solution is stirred at 300 rpm for 2 hours. For protonation, 2 drops of concentrated hydrochloric acid (HC1) are added to the solution. Then, 15% aqueous citric acid and 0.2 gram of borax is added to the PVA solution as cross linking agent and the mixture is stirred for an additional 2 hours. When the solution becomes viscous, 0.05 gram of discrete and hybrid biochar's are added in total to the mixture, ensuring thorough dispersion and cast into the petri dish plates. The solution is dried overnight in hot air oven at 80°C, and then the membranes are peeled from the petri dish. The membranes prepared from 7.5% citric acid are soluble in water, whereas, the membranes from 22.5% citric acid are brittle in nature.
Example 3: Dye adsorption using polymer membrane
Methylene blue and Congo red are used for the adsorption studies and dye concentration of 50 ppm is maintained throughout the experimentation. Biochar infused polymer membranes of size 1 cm x 1 cm is immersed in 25 mL of the prepared dye solution to evaluate its adsorption capacity. Observations are made over a period of 3 hours by varying the pH of the dye solutions from 3 to 11. The activated and unactivated biochar produced from muffle furnace is utilized in these membranes, as its unique properties can enhance adsorption behaviour.
I/We claim,
1. A method for fabricating a polymer membrane for dye adsorption comprises of biochar from agro-based waste peels by incorporating into a Polyvinyl alcohol (PVA) matrix with varying weight percentage of cross linking agent viz., 7.5%, 15% and 22.5% to form a membrane. Unactivated and activated biochar under acidic and alkaline conditions prepared from onion and garlic waste peels are pyrolyzed at varied temperatures viz., 200°C, 400°C and 600°C. Biochar is utilized for fabrication of polymer membranes in discrete and hybrid mode. The effect of membranes is studied using anionic and cationic dye by varying the pH from 3 to 11.
2. The method of claim 1, wherein, the biochar pyrolyzed at different temperature viz., 200°C, 400°C and 600°C, the preferred temperature is 400°C and 600°C where the material possessed the stable property.
3. The method of claim 1, wherein the surface area of the biochar activated under acid and alkaline condition, the acid activated possessed higher surface area in the range of 89-98 m2/g than that of alkaline conditions 20-50 m2/g.
4. The method of claim 1, wherein the cross linker at different weight percentages, the membranes fabricated at 15wt% is found to be the most stable than that of 7.5wt% and 22.5wt%.
5. The method of claim 1, wherein using the methylene blue dye for acid activated, alkali activated and unactivated biochar for dye adsorption, the better dye removal is obtained for acid activated hybrid biochar infused membrane
6. The method of claim 1, wherein using the congo red dye for acid activated, alkali activated and unactivated biochar for dye adsorption, the better dye removal is obtained for alkali activated hybrid biochar infused membrane
7. The method of claim 1, wherein acid activated biochar membrane has high dye adsorption capacity up to 95% due to its high surface area of biochar.
8. A polymer membrane produced by the method of claim 1, suitable for dye adsorption applications in wastewater treatment.

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