Corncob Carbon Research Articles

Characterization and electrochemical properties analysis of reduced graphene oxide from corncob carbon as an electrode candidate: Synthesized using modified Hummers method

This research aims to synthesize and characterize reduced graphene oxide (RGO), as well as analyse its electrochemical properties. The synthesis of RGO material from corn cobs went through several stage: carbonization, oxidation and reduction. The synthesis of RGO used a modified Hummer method, and was reduced using the reducing agent ascorbic acid. The synthesized RGO was then characterized using Fourier Transform Independent Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). Electrochemical analysis using the cyclic voltammetry method, the specific capacitance value obtained showed that RGO had a higher capacitance value than GO. The research results showed that carbon from corn cobs, which has not been utilized optimally, can be synthesized as a basic material for making RGO as a quite promising material.

Study on the removal of high nitrate-nitrogen concentration from pig farm wastewater by heterotrophic and sulphur autotrophic synergistic denitrification filter process

Following the anaerobic fermentation process in a lagoon, the effluent from pig wastewater exhibited elevated levels of total nitrogen and nitrate nitrogen. The utilization of simple sulphur-limestone autotrophic denitrification resulted in a sluggish reaction rate and relatively moderate removal load. To enhance the efficacy of the sulphur autotrophic denitrification process, a strategy was implemented involving the introduction of a limited quantity of corncobs as a slow-release carbon source. This addition was made to a sulphur-limestone autotrophic denitrification reactor that was being operated continuously and stably. Furthermore, the volume ratio of the corncobs added was progressively increased. This study examines the alterations in nitrate nitrogen, chemical oxygen demand (COD), sulphate, and alkali consumption within the sulphur-limestone autotrophic denitrification reactor, both prior to and after the introduction of corncobs. This study examines the operational efficiency and reaction mechanism of a sulfur-limestone autotrophic denitrification reactor that is enhanced by the utilization of corncobs as a slow-release carbon source. The findings of the study indicate that the inclusion of maize cob carbon source in the sulphur limestone autotrophic denitrification process resulted in improved effectiveness in removing nitrate and nitrogen. Additionally, when considering the three different ratios of corncob carbon source, the process exhibited a chemical oxygen demand (COD) removal rate exceeding 42%. The observed trend in the consumption of alkalinity in both the pure sulphur limestone autotrophic denitrification process and the sulphur limestone autotrophic denitrification process augmented by the three types of corncob slow-release carbon sources indicated an increase with time. The concentration of nitrate-nitrogen in the influent water exhibited a negative correlation with the length of the reactor flow-through. The addition of a slow-release carbon source derived from corncob greatly enhanced the autotrophic denitrification and denitrification impact in the three reactors. Moreover, there was an observed increase in the trend of heterotrophic denitrification as the amount of carbon source added increased. The efficacy of the mixotrophic denitrification process surpassed that of the sulphur-limestone autotrophic denitrification method in the treatment of nitrate-nitrogen wastewater characterized by a high concentration of nitrate-nitrogen. The former exhibited a higher denitrification rate and resulted in lower levels of sulphate ions and alkalinity production.

Hydrothermal carbonization of corncob for hydrochar production and its combustion reactivity in a blast furnace.

A key factor restricting the application of biochar in the steel industry is its high-quality upgrading. This paper evaluated the characteristics of hydrochar produced by HTC (hydrothermal carbonization) process of corncob to be used as a solid fuel. HTC temperatures (240-300°C) and HTC water-reused times (1-3 times) were examined for their effects on hydrochar yield, physicochemical characteristics, and combustion properties. The results showed hydrochar yields, O/C, and H/C parameters decreased as HTC temperature and water-reused times increased, while its high heating value increased. Due to dehydration and decarboxylation, hydrochar showed similar characteristics to those in bituminous coal. The removal efficiency of alkali metal K reached 99% after HTC treatment. Carbonaceous hydrochar had become more compact, orderly, and stable with increasing amounts of aromatic functional groups, C = C, and C = O. Hydrochar, as a biofuel, has higher ignition energy and is more stable than corncob due to its high carbonaceous order degree. To calculate combustion kinetic parameters, the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods were applied. The results revealed that Eα (average activation energy) was quite similar between the two models. HC-300 had an Eα of 262kJ/mol. HTC could be an efficient way to reutilize corncob biomass into clean biofuels with high calorific value.

Comparison of natural corn cob and carbon corn cob in the purification of used cooking oil with shaker operation

The research aims to determine the adsorption ability and modeling of adsorption kinetics to purify used cooking oil using natural and carbonized corn cob adsorbent, which is economical, efficient, and sustainable due to its low price, renewability, and simplicity. Samples of used cooking oil were taken as much as 100 ml with an adsorbent mass of 3 g and particle size of 50 mesh and stirred using a shaker. Based on the results, it was found that the effect of carbonization was able to reduce the turbidity of used cooking oil, whereas for the use of natural corn cob adsorbent, at 20 minutes, turbidity of 59.0 NTU was obtained and 45.2 NTU was obtained after the adsorption process for 5 hours, while for the use of corn cob carbon adsorbent, a turbidity of 62.8 NTU was obtained for the same adsorbent size and 39.8 NTU was obtained after the adsorption process for 5 hours. Chemical interaction trends were also obtained, as shown in the second-order pseudo graph with coefficient of determination (R2) values close to 1 using natural corn cob and corn cob carbon adsorbents, namely 0.9965 and 0.9959.

Purification of used cooking oil using natural corn cob and carbon corn cob as adsorbent with batch operation

Adsorption is one of the processes used to purify used cooking oil by using adsorbents from natural and carbonized corn cob as part of sustainability. The adsorption process is chosen because it is more economical, efficient, relatively affordable cost, and can be regenerated. This study was conducted in batches to observe changes in the quality of used cooking oil at certain time intervals and to determine the modeling of adsorption kinetics on natural corn cob and carbonized corn cob adsorbents. The sample of this study is 100 ml of used cooking oil with adsorbents in the form of natural corn cob and carbonized corn cob with a mass of 3 grams and a particle size of 70 mesh. This study’s best adsorption result is corn cob carbon adsorbent. This can be seen from the final turbidity value of 37.3 NTU compared to the natural corn cob adsorbent of 37.6 NTU. This study found that the adsorption process that occurs has chemical interactions as evidenced by second-order pseudo-modeling, which has a correlation coefficient close to one.

Effects of corncob carbon on peanut growth and soil properties

In this paper, corncob biochar was prepared by pyrolysis, and the basic physicochemical properties of the carbon were analysed by characterisation, and potting tests were used to study the effects of different carbon application rates on peanut growth indexes and soil conventional physicochemical properties. The results showed that the corncob carbon at 500°C for 30 min was suitable for soil improvement; the carbon had a pH of 9.98 and could regulate soil pH; it had a rich pore structure with a specific surface area of 11.6 m2·g-1, which could improve soil pore density; and its N,P,K contents were 5.8,8.3,49.5 g·kg-1, respectively, which could provide exogenous nutrients to the soil. The higher the amount of carbon applied, the better the effect on soil physicochemical properties and yield promotion. When the amount of carbon applied was 7%, the soil capacity was reduced by 8.8%, the plant height was reduced by 5.5%, the stem thickness was increased by 18.4%; soil pH increased by 3%, CEC by 20.2 %, and organic matter by 52.03%, resulting in a 40.8% increase in peanut yield.. This corncob carbon has good physicochemical properties and is an ideal soil conditioner.

Mathematical modeling and experimental validation of a novel Circulating Oxygenation Biofilm Equipment (COBE) for the management of decentralized wastewater treatment

The difficulties of management were the key barriers to the promotion of decentralized wastewater treatment in remote areas. In this study, a novel decentralized Circulating Oxygenation Biofilm Equipment (COBE) and its remote management potential based on mathematical modeling were investigated. The COBE is an integrated biofilm reactor that employs drippage aeration and enables oxygenation, filtration, and effluent processes to be controlled, thus providing convenience for controlling. The model for the COBE describing drippage aeration, comprehensive ammonia-related microbes, and corncob carbon source release process was studied to uncover the impacts of operational conditions on decentralized wastewater treatment in the COBE system. The equipment regulation parameter (circulating oxygenation ratio) was found to be linearly correlated with the oxygen mass transfer coefficient. This discovery enabled highly accurate prediction of COD, NH4–N, and TN concentrations in the equipment effluent at various scenarios. The comprehensive ammonia oxidation biological model indicated that the model could duplicate the actual situation of the succession of ammonia metabolizing related microorganisms. Comammox and ammonia-oxidizing archaea (AOA) dominated ammonia metabolism in this equipment rather than conventional ammonium-oxidizing bacteria (AOB). This study could contribute to the Internet of Things system construction of decentralized wastewater treatment equipment, and provide a solution for timely decentralized equipment management in remote areas.

Electrode and electrolyte additive synergy effect for improving the capacity and supporting a high voltage plateau of aqueous rechargeable zinc iodine batteries

Aqueous rechargeable zinc-iodine batteries (ZIBs) coupled with a metal anode are promising candidates for next-generation electrochemical energy storage systems due to their high energy density, excellent safety and low cost. In this work, we develop a facile strategy for high performance ZIBs by adopting ZnCl2 electrolyte, KI additives and activated porous corncob carbon (APCC) as a cathode. We find that ZnCl2 electrolyte could significantly activate the I0/I+ redox behavior, and expand traditional conversion to four-electron transfer process, leading to a high discharge voltage plateau. Moreover, the APCC with the high surface area and conductivity, and strong adsorption ability can effectively immobilize I2. Notably, the introduction of KI additives provides more active materials. Consequently, an aqueous Zn battery based on a Zn metal anode and ZnCl2 electrolyte delivers an ultra-flat plateau at 1.15 V, which contributes to 92.2% of the capacity and 89.2% of the energy density. Our work offers an efficient method to fabricate high-performance ZIBs with eco-friendliness.

Laccase Immobilization on Activated Carbon from Hydrothermal Carbonization of Corn Cob

Laccase Immobilization on Activated Carbon from Hydrothermal Carbonization of Corn Cob

Comparative Study of Biochars from the Retort Co-Carbonization of Corn Cob and Polyethylene Wastes

Biochar is a pyrogenic, carbon-rich by-product of the products of biomass valorization. Its applications include source of heat, carbon sequestration, soil improvement, adsorbent, chelating agent and niche for micro-organism growth. The study focused on the retort carbonization of corn cob and co-carbonization of corn cob and polyethylene waste for comparative studies using a top-lit updraft conversion reactor with retort heating. The properties of the biochars were analyzed using Scanning Electron Microscopy - Energy Dispersive X-ray (SEM-EDX) and Branueur-Emmet-Teller (BET). Results revealed the ordinary biochar had a homogeneous surface with repeating patterns forming a honeycomb-like structure with a 62% carbon composition while the hybrid biochar had a heterogeneous surface with a rough pattern and ridges with an 80% carbon composition. The heterogeneity and increase in carbon composition observed in the hybrid biochar were attributed to the presence of the polyethylene waste. Biochars with high carbon contents can find their applications in areas of carbon sequestrations. The biochar and hybrid biochar were found to be porous with specific surface areas of 392.5 m2/g and 889.9 m2/g respectively. The high specific surface area of the hybrid biochar produced highlights its potential as an adsorbent. Biochar with high levels of porosity is also useful in soil enhancement. The co-carbonization of corncob and polyethylene waste has been established to be a means of conversion of both agricultural and plastic wastes into biochar with various potential applications.

Recovery of electron and carbon source from agricultural waste corncob by microbial electrochemical system to enhance wastewater denitrification

The denitrification process in wastewater treatment plants (WWTPs) is limited by insufficient carbon sources. Agricultural waste corncob was investigated for its feasibility as a low-cost carbon source for efficient denitrification. The results showed that the corncob as the carbon source exhibited a similar denitrification rate (19.01 ± 0.03 gNO3−-N/m3d) to that of the traditional carbon source sodium acetate (19.13 ± 0.37 gNO3−-N/m3d). When filling corncob into a microbial electrochemical system (MES) three-dimensional anode, the release of corncob carbon sources was well controlled with an improved denitrification rate (20.73 ± 0.20 gNO3−-N/m3d). Carbon source and electron recovered from corncob led to autotrophic denitrification and heterotrophic denitrification occurred in the MES cathode, which synergistically improved the denitrification performance of the system. The proposed strategy for enhanced nitrogen removal by autotrophic coupled with heterotrophic denitrification using agricultural waste corncob as the sole carbon source opened up an attractive route for low-cost and safe deep nitrogen removal in WWTPs and resource utilization for agricultural waste corncob.

Influence of adsorption sites of biochar on its adsorption performance for sulfamethoxazole

In this study, the effects of various types of key adsorption sites on biochar were investigated on its adsorption capacity for sulfamethoxazole (SMX). The biochar obtained by carbonization of corncob at 800 °C (named CC800) was applied to the adsorption of SMX in aqueous environment. The adsorption of SMX by CC800 exhibited a “Three-stage downward adsorption ladder” characteristic in the whole pH range, which was attributed to the different mechanisms corresponding to different adsorption sites of CC800. The organic solvent method and heat treatment method restored the adsorption sites of CC800 after saturated adsorption. And the results revealed that the pore structure and aromatic structure under acidic conditions, and surface functional groups and pore structure under alkaline conditions were confirmed to be key SMX adsorption sites. The adsorption energies of each adsorption mechanism were calculated by density functional theory (DFT), and their order was (−)CAHB (–COO–) > π+−π EDA interaction > (−)CAHB (–O–) > pore filling mechanism > π−π EDA interaction. Based on the above studies, the adsorption performance of biochar to SMX can be improved by targeted modification of its micropore structure, surface functional groups, and aromatic structures.

Effect of corn cob carbon quantum dots and areca husk microfiber on EMI shielding effectiveness of flexible PVA thin film at 8–20GHz frequency bands

Effect of corn cob carbon quantum dots and areca husk microfiber on EMI shielding effectiveness of flexible PVA thin film at 8–20GHz frequency bands

Analysis of Phase and Energy Band Gap Width of Corncob Carbon-PEG 4000

This study aims to identify and analyze the band gap width of the carbon phase produced from corncobs mixed with PEG-4000 to see the surface area of the corncob carbon phase. First, the characterization test was carried out using Scanning Electron Microscope Energy-Dispersive X-ray (SEM-EDX) spectroscopy to determine the morphology and Ultraviolet–Visible (UV-Vis) spectroscopy to determine the band gap width of corncob carbon. Then, adding Polyethylene Glycol (PEG) 4000 at a specific concentration to develop the potential of corncob carbon. Finally, the corncob-PEG 4000 carbon reduction process was sifted through and tested by UV-Vis spectroscopy, and the energy gap value was 0.954 eV. DOI: 10.17977/um024v7i22022p142

Carbon sources derived from corncobs enhanced nitrogen removal in SBBR treating low C/N domestic sewage

Domestic sewage has the characteristics of low carbon to nitrogen ratio (C/N), so an external carbon source is required to increase the denitrification performance of the system. Agricultural waste carbon sources have attracted much attention due to their wide range of sources and low cost. Therefore, this study investigated the corncob pretreated with acid and alkali as the external carbon source. Then the effect on nitrogen removal was further determined by sequencing batch biofilm reactor (SBBR). The results showed that the alkali pre-treated corncob had a higher carbon release capacity; the COD cumulative release amount was 123.5 mg/g·L within 16 days. It had an excellent denitrification rate, with a total nitrogen removal rate of 90.1%. In addition, the denitrification rate of alkali pre-treated corncob (100 g) as a carbon source was equivalent to that of sodium acetate (influent C/N ratio: 15). At this time, the total nitrogen removal rate reached a maximum of more than 90%. Microbial community analysis discovered that microbial abundance and diversity increased after adding corncob carbon sources. Among them, the contents of Firmicutes, Macellibacteroides, and Hydrogenophaga were significantly increased, which played a decisive role in degrading cellulose and using cellulose as a carbon source for denitrification. Besides, denitrifying bacteria such as Proteobacteria, Thauera, and Gemmatimonas were also abundantly aggregated, indicating that the denitrification in SBBR was enhanced. These findings collectively suggest that alkali pre-treatment of corncob as a carbon source could effectively improve the denitrification performance of low C/N ratio wastewater.

Adsorption of Methyl Orange on Corncob Activated Carbon: Kinetic, Equilibrium, and Thermodynamic Studies

H3PO4 activated corncob carbon was used for removal of methyl orange. Characterization of the prepared carbon showed that it has many pores with a specific surface area equal to 714 m2 g-1. During this study, the concentration of methyl orange was monitored using a UV-visible spectrophotometer. The kinetic study of the adsorption of methyl orange on activated carbon was performed and the adsorption rate was found to be consistent with pseudo-second order kinetics with 240 min as the equilibrium time. The equilibrium adsorption revealed that the experimental data better fit the Langmuir isotherm model for methyl orange removal. It is noted that for optimal removal of 10 mg L-1 methyl orange in a 25 mL volume, 0.3 g of activated carbon and a pH equal to 2.04 are required. The maximum monolayer adsorption capacity for methyl orange removal was found to be 107.527 mg g-1. Analysis of thermodynamic parameters showed that the adsorption process of methyl orange on activated carbon is physisorption, spontaneous and endothermic.

Comparative study on fuel characteristics and pyrolysis kinetics of corn residue-based hydrochar produced via microwave hydrothermal carbonization

Corn residues are an important source of bioenergy. Due to their highly diverse lignocellulosic structures, the hydrochar produced from microwave-assisted carbonization of different corn residues may have distinct fuel properties and pyrolysis kinetics. This study comprehensively investigated the effect of processing temperature on the basic fuel properties of hydrochar and examined the pyrolysis behavior of hydrochar as a precursor through kinetic analysis. The results indicate that the fuel quality of corn straw hydrochar prepared by microwave-assisted hydrothermal carbonization at 230 °C was significantly improved over that of its feedstock, with a higher heating value of approximately 20.7 MJ/kg. Hydrochar prepared by microwave-assisted hydrothermal carbonization of corn cob at 230 °C presents noticeable environmental advantages because it contains the lowest ash and nitrogen contents (0.5% and 0.5%, respectively) and lower sulfur content (0.05%). Moreover, regarding the kinetic modeling, the Doyle and Coats-Redfern models, which are both first-order and single-step kinetic models, were identified as satisfactory in interpreting the key pyrolysis kinetic parameters. Additionally, the microwave-assisted hydrothermal process increased the apparent activation energy of hydrochar due to the increase in crystallinity and the increase in the number of CC and CO bonds.

Non-covalent doping of carbon nitride with biochar: Boosted peroxymonosulfate activation performance and unexpected singlet oxygen evolution mechanism

• Non-covalent assembled carbon nitride/biochar composite is synthesized in one-pot. • π-Electron delocalization is triggered while pristine robust skeleton is retained. • CNBC rivals popular N-carbon in PMS activation and exhibits better durability. • Singlet oxygen is the major oxidant and superoxide radical acts as intermediates. • PMS first loses electrons on CNBC surface along with the cleavage of its S–O bond. A noncovalent functionalization approach was implemented using graphitic biochar (BC) as dopant to manipulate electronic properties of polymeric carbon nitride (PCN) while preserving its robust geometric skeleton. By fine-tuning the mass proportions of precursors during copolymerization, the carbonization of corncob was successfully confined in the PCN interlayers. An electron transport highway from PCN to BC was built owing to the π-electron delocalization. As a result, the non-covalent assembled PCN/BC composite rivaled popular nitrogen-doped carbon materials in activating peroxymonosulfate (PMS), and meanwhile exhibited superior durability. Singlet oxygen ( 1 O 2 ) was identified as the primary reactive oxygen species. Combining theoretical calculations and in-situ detections, a novel 1 O 2 evolution route with respect to the dissociation of PMS at the S/O site and the formation of superoxide radical was decoded. This work offers a new idea for the synthesis of durable PMS activators and enriches mechanistic understanding of PMS decomposition over metal-free catalysts.

Adsorption of Petroleum Hydrocarbon by Modified Biomass Carbon

In order to improve the oil adsorption performance of biomass carbon, a new oil removal adsorbent was prepared by modifying natural material. Hydrophobic agent is used as modifier to graft biomass carbon. The structural characteristics and microstructure of biomass carbon treated by modifiers are characterized by FTIR spectroscopy and SEM observation. The results showed that self-made biomass charcoal has good floatability, and biomass carbon treated by the hydrophobic agent has a higher oil adsorption capacity than those of untreated ones. Peanut shell carbon and corn cob carbon modified by nano-SiO2 dispersant obtained the best results with an oil absorption rate of about 1.5 g/g and an oil retention rate of about 95%. As determinate by GC/MS, the modified biomass carbon before and after the adsorption of marine oil, the alkane changed significantly, indicating that the adsorption capacity of oil is very obvious.

Removal of Emulsified Oil in Wastewater by Corn Cob Carbon

Oil pollution is a serious environmental concern which is caused by rapid industrial development around the world. In this study, corn cob carbon was used as a natural adsorbent for emulsified oil wastewater remediation. Three parameters that were studied include contact time, dosage of corn cob carbon and concentration of emulsified oil wastewater. The physical and chemical structures of raw and corn cob carbon were characterized. The corn cob carbon showed good efficiency in emulsified oil removal with a percentage of 96% at 2 hours contact time, 1 g of corn cob carbon and 5% of emulsified oil wastewater concentration. The apparent porosity of corn cob carbon was the reason for the sinking of emulsified oil particles absorbed on the surface of corn cob carbon. TGA shown 3.60% and 58.17% of mass loss within the first and second thermal decomposition, respectively. The functional groups of corn cob samples are C-H, -C≡C-, C=C, -C-H and C-O. SEM analysis showed that pores were found in the corn cob carbon and a layer of oil was present on its surface after the adsorption process. Therefore, corn cob carbon could be considered as an alternative to remove emulsified oil in wastewater due to its good adsorption capacity and low secondary pollution.