Groundnut Shell Research Articles

Investigation of properties of soils stabilised with groundnut waste

Improvement of soil strength has gained a wider and increasing acceptance in civil engineering applications. This study therefore investigat-ed the effects of coarse content of groundnut shell ash on the properties of selected lateritic soils. To achieve the aim of the study, soil sam-ples were collected from two identified active borrow pits. The following geotechnical tests were conducted on the soil samples in their natural state, using standard procedures: natural moisture content, specific gravity, grain size analysis, Atterberg limits, compaction and California bearing ratio. Subsequently, the soils were treated with coarse content (part retained on 425 µm BS sieve) of groundnut shell ash at 2 %, 4 % and 6 % proportions by weight of dry soil. Results showed that the degree of laterisation is high in the two soil samples, having specific gravity values of 2.84 and 2.72 respectively. Results of Atterberg limit tests and grain size analysis showed that the soils belong to A-2-7 using AASHTO classification system. 6 % groundnut shell ash gave the lowest plasticity index for first sample, while 2 % ground-nut shell ash gave the lowest plasticity index for second sample. Also, 2 % groundnut shell ash gave the lowest optimum moisture content for first sample, while 6 % groundnut shell ash gave the lowest optimum moisture content for the second sample. Similarly, 2 % groundnut shell ash gave the highest maximum dry density for first sample, while 4 % groundnut shell ash gave the highest maximum dry density for second sample The California bearing ratio reached a maximum value of 4 % at 6 % groundnut shell ash, for first sample; it increased to 14 % at 2 % groundnut shell ash, for second soil sample. The study concluded that lateritic soils can be modified with coarse component of groundnut shell ash. Â

A computational framework for combustion of powdered solid fuels in a MILD reactor using a novel devolatilisation model

In this paper, a computational framework for modelling the thermochemical conversion of powdered solid fuels in a MILD reactor is presented. Specific fuels of interest are high ash coals and lignocellulosic biomass. The novelty of the current framework lies in recognising that the devolatilisation process of charring fuels like biomass and coal is surface heat transfer limited at heating rates relevant to practical systems. The in-house unified ignition devolatilisation model developed for pelletised biomass in a packed bed configuration is extended to powdered fuels. Comprehensive modelling of a 50 kW solid fuel MILD reactor is accomplished by integrating the particle model with a commercially available CFD code. Unsteady Lagrangian particle tracking in an Eulerian gas phase is used to resolve the temperature profile in the reactor. Heat loss from the reactor walls, an essential parameter for obtaining accurate temperature profiles, is obtained by striking an energy balance over the entire domain using experimental data (from the earlier work of the authors). Results of numerical simulations with two different fuels (powdered coal and groundnut shells) covering a wide range of flow conditions obtained with the framework are presented in the current study. Normalised spatial temperature variation and the O mole fraction profiles with the two fuels indicate that the reactor operates in MILD mode. The temperature profiles predicted with the framework are in satisfactory agreement with the experimental results. The modelling approach successfully predicts the operational regimes of the reactor. A noteworthy feature of the new framework is its applicability in predicting devolatilisation of different fuels without the need for any adjustable constants. This enables the use of this framework as a predictive design tool.

Effect of pretreatment and biomass blending on bio-oil and biochar quality from two-step slow pyrolysis of rice straw

This study investigated biomass blending and water washing to improve product quality from two-step pyrolysis of rice straw. Rice straw (RS) was mixed with groundnut shells (GNS) and wheat straw (WS) in different weight ratios. Blending RS with GNS/WS in a 1:1 ratio increased the total bio-oil yields by 7-9% and reduced the pyrolysis gas and char yields by 5-7% and < 2%, respectively. RS was washed with water separately to examine the effect of removing water-soluble ash elements. The optimum washing duration was 60 min; the ash removal efficiency was then 26%. The bio-oil yields from washed straw increased by 4% over unwashed straw, and pyrolysis gas yields decreased. Combining the washing and blending processes increased the levoglucosan yield by 1.6-2.1 times compared to unwashed RS, and the water content in bio-oil was reduced by ∼ 10%. Moreover, the biochar samples obtained after pyrolysis of washed biomass blends had potential fuel applications owing to low fouling or slagging propensity. They also had possible use in the soil for adsorption of soil contaminants and increasing acidic soil pH, with likely stability of ∼ 1000 years in the ground. These results provide a promising alternative for efficiently converting rice straw to multiple value-added products.

Factors influencing sorption of trace elements in contaminated waters onto ground nut shells

Biosorbent materials such as nut shells has been considered a promising alternative to the classic methods to remove potentially toxic elements from contaminated waters, improving water quality for other uses. The present study evaluated the sorption capacity of almond, hazelnut, pistachio and walnut shells for the single and simultaneous removal of As, Cd, Co, Hg, Ni, Pb and Zn from contaminated waters. The influence of key parameters such as sorbent dose, ionic strength (ultrapure water vs. mineral water), element competition (mono-vs. multi-element spiked solution) and initial element concentration (maximum allowed value in wastewater discharges and ten times lower) was assessed. Hazelnut shells stood out as the material with higher potential to remove Cd, Co, Hg, Ni, Pb and Zn in the tested conditions, achieving up to 99% of removal (Cd and Pb). Arsenic was not removed by none of the studied materials and the removal of Cr was only obtained in a simple matrix and in mono-element solution (41% of removal). An increase of matrix complexity negatively affected the sorption capacity of all the biosorbents in the removal of all the elements tested. The same behavior was obtained when the elements were simultaneously present in solution, with Pb, Cd and Hg being highly influenced by the presence of other elements. The increase in sorbent dose from 1 to 5 g/L allowed to at least duplicate the removal of Cd, Co, Ni and Zn by all the biosorbents. When decreasing the initial element concentration ten times the maximum allowed value in wastewater discharges, a significant increase of elements removal was attained, more pronounced for Hg and Pb. The possibility to change initial conditions towards high efficiencies validate the high potential of those biosorbents to be used in water remediation, with special focus on hazelnut shells, although other sorbents such as walnut or almond shells can be considered efficient with appropriate initial conditions and depending on the target elements to be removed.

Preparation and characterization of bio-composite films obtained from coconut coir and groundnut shell for food packaging

Preparation and characterization of bio-composite films obtained from coconut coir and groundnut shell for food packaging

Modelling the effects of particle size pretreatment method on biogas yield of groundnut shells.

Optimising biogas yields from anaerobic digestion of organic wastes is significant to maximum energy recovery in the biodigestion process and has become an important topic of interest. Substrate particle size is an important process parameter in biogas production, and it precedes other pretreatments methods for the majority of the lignocellulose materials. Optimisation of biogas yield using Response Surface Methodology (RSM) was done, and temperature, hydraulic retention time and particle size were considered variables to develop the predictive models. Pretreatment of groundnut shells was investigated using particle size reduction of mechanical pretreatment methods. After pretreatment, 30 samples were digested in a batch digester at mesophilic temperature. The experimental results showed that the temperature, hydraulic retention time and particle size had significant effects of interaction (p < 0.05). The optimum experimental and predicted yields are: 44.70 and 42.92 (lNkgoDM) organic dry matter biogas yield, 20.80 and 19.09 (lN/kgFM) fresh mass biogas yield, 24.00 and 22.68 (lNCH4oDM) organic dry methane yield and 12.30 and 15.59 (lNCH4FM) fresh mass methane yield, respectively. The R2 recorded for the four yield components were 0.6268, 0.5875, 0.6109 and 0.5547. These values seem to be lower and a sign of the average fit of the model. Biogas production from groundnut shells was significantly improved with statistical optimisation and the pretreatment method.

Blended formaldehyde adhesive bonded particleboards made from groundnut shell and rice husk wastes

Blended formaldehyde adhesive bonded particleboards made from groundnut shell and rice husk wastes

Synergistic and sustainable utilization of coconut shell ash and groundnut shell ash in ternary blended concrete.

The quest for eco-sustainable binders like agro-wastes in concrete to reduce the carbon footprint caused by cement production has been ongoing among researchers recently. The application of agro-waste-based cementitious materials in binary concrete has been said to improve concrete performance lately. Coconut and groundnut shells are available in abundant quantities and disposed of as waste in many world regions. Therefore, the use of coconut shell ash (CSA) and groundnut shell ash (GSA) in a ternary blend provides synergistic benefits with Portland cement (PC) and may be sustainably utilized in concrete as ternary cementitious material (TCM). Therefore, this study presents concrete performance with CSA and GSA in a grade 30 ternary concrete. Two hundred ten numbers of standard concrete samples were cast for checking the fresh and mechanical properties of concrete at curing ages of 7, 28, and 90 days. After 28-day curing, the experimental results show an increment in compressive, tensile, and flexural strength by 11.62%, 8.39%, and 9.46% at 10% TCM cement replacement, respectively. The concrete density and permeability coefficient reduce as TCM's content increases. The modulus of elasticity after 90 days improved with the addition of TCM. The concrete's sustainability assessment indicated that the emitted carbon for concrete decreased by around 16% using 20% TCM in concrete. However, the workability of fresh concrete declines as TCM content increases.

Termicidal activity of two agro wastes against two termite castes, subterranean termites, Macrotermes subhyalinus [Isoptera: Termitidae

Toxicity activities of two agricultural wastes, cowpea pod and groundnut shell against worker and soldier termites were investigated under appropriate laboratory conditions (temperature 28±2 °C; 75 ± 5% relative humidity). The agricultural wastes powders were admixed separately at 1 g, 3 g, 6 g, 9 g and 12 g/40 g of wood shaving while wastes extracts was tested at concentrations 1%, 3%, 6%, 9% and 12%/40 g of wood shaving in a 500 ml plastic container. The termiticidal effects of the agricultural waste powders and extracts against worker and soldier termites were examined for 12 and 24 h. Cowpea pod powder caused 100% mortality of workers termite at 12 g after 24 h of exposure. Cowpea pod powder compared to groundnut shell powder was the most toxic to workers and soldiers of termites causing high % mortality at all tested concentrations. Groundnut shell powders also caused 97.5% mortality of soldier termites at concentration 12 g after 24 h of treatment. There were no significant differences (p > 0.05) among the agricultural wastes tested (cowpea pod and groundnut shell extracts) after 24 h of treatment. Cowpea pod extract evoked 100% mortality of workers termite at concentration 9% after 24 h of treatment. Groundnut pod extract was the least toxic to workers and soldiers of termites compared to the effect of cowpea pod extract with higher lethal concentration. The use of agricultural wastes such as cowpea pod and groundnut shell as termiticides will reduce pollution of these wastes in our environment and decrease use of synthetic chemical insecticide.

Physical and Mechanical Characterization of Bamboo Fiber/Groundnut Shell/Copper Particle/MWCNT‐Filled Epoxy Hybrid Polymer Nanocomposites

Current research finds the suitability of natural fiber‐reinforced polymer composites for industrial, automotive, marine, aerospace, and military vehicle applications, among others; they process being lightweight, high strength, ecofriendly, recyclable, and biodegradable. Bamboo fiber (Bambusoideae) mat, groundnut shell (Cocos nucifera) powder, copper particle, and multiwalled carbon nanotubes (MWCNT) fillers with epoxy resin are the primary materials. The key responsibility of MWCNT as a nanofiller is to improve the performance of materials by more than 80% and to attract the desirable properties such as high specific energy absorption of CNTs. An extensive investigation was carried out to determine the weight ratio between the total density and the water absorption rate of the composite. The maximal tensile and flexural strengths derived from EBGCM2 (E: epoxy; B: bamboo; G: groundnut shell; C: copper particle; M: MWCNT) were 50.66 MPa and 59.03 MPa, respectively. Addition of MWCNTs to specimens EBGCM2 and EBGCM3 and bonding the filler matrix by homogeneous mixing, but few nanoparticles are seen agglomerated. Flexural abilities of groundnut fiber/filler loading to strengthen the hybrid nanocomposites and the impact strength both quite improved than EB1 specimen. The neat epoxy and bamboo fiber composite (EB1) achieved 87.5 Shore‐D hardness. SEM revealed (EBGCM3) improved interfacial adhesion between fiber and epoxy resin, but few nanoparticles are agglomerated, small molecules linked between the fibrous matrix, and the binding elements trapped in neighboring atoms, forming structural chains by the polymerization process.

Energy Densification of Groundnut Shell through Microwave-Assisted Hydrothermal Carbonization

Modern technology of microwave synthesis was utilized for hydrochar production from groundnut shell biomass. Hydrochar was produced at three different temperatures (180, 200, and 220°C) with 20 minutes of holding time and analyzed for the physicochemical characteristics. The yield of hydrochar and hydrocrude were in the range of 45 to 61 % and 51 to 56 % respectively. The maximum value of the higher heating value of 19.11 MJ/kg was obtained for hydrochar produced at 220°C, which is similar to the higher heating value of lignite (19 MJ/kg). The energy densification ratio of respective hydrochar was 1.13 with 51.77 % energy yield. The result implied that microwave-assisted hydrothermal carbonization was an energyefficient method to produce hydrochar. Hydrochar produced from groundnut shells was an eco-friendly, energy enriched product that can be used as a solid fuel.

Study of Energy Value Estimated from Mixture Design Matrix ofSome Agricultural Waste Blends pulverized nut shells

Energy sources that are sustainable and renewable include biomass resources. Efficient use of these biomass resources to provide a worldwide energy supply that is sustainable. The techniques that enhance this biomass's energy potential require a thorough grasp of its physicochemical characteristics. The energy content of biomass resources (HHV or NHV) is a crucial factor to consider when determining their suitability for energy production. In this work, proximate assessments of biomass materials (agricultural residues) and their blends were developed based on some published empirical model equations to investigate the impact on their net and high heating value.EFB, corncob, and groundnut shell blends' computed net heating value (NHV) and high heating value (HHV) were found to be between 16.157 and 18.483 MJ/kg. According to the findings, agricultural residues are excellent substrates for the generation of solid fuel. The energy values of biomass samples might also be calculated using the empirical formulae based on their nearby characteristics.

An experimental study on compressive properties of high density polyethylene-nano alumina-groundnut shell hybrid composites

In recent years, bio-fibers have become increasingly popular as reinforcements for thermoplastics and thermosets. Research into the use of natural fibers such flax, bamboo, sisal, hemp, and jute as reinforcing elements in the production of various composites has been considerable. Groundnut shell particles and refractory alumina powder were combined with high density polyethylene (HDPE) polymer matrix to create new bio-based composites in this study. The results were promising. Composite boards were synthesized by with HDPE with randomly distributed nano alumina and groundnut shell particles with volume percentages of 95:0:5, 95:2.5:2.5 and 95:5:0. ASTM standards were used to evaluate the compressive, shore hardness and water intake characteristics of the composites. The highest compressive load, compressive strength, increase in area, maximum displacement, displacement at break and compressive strain were analyzed for the specimen having HDPE, nano alumina and groundnut shell particles proportion 95:2.5:2.5. Using HDPE, nano alumina, and groundnut shell particles, Possibly a composite might be produced that could replace wood in many settings.

Preparation and characterization of activated carbon from groundnut and egg shells as viable precursors for adsorption

This study was carried out to prepare groundnut shell (GS) and eggshell (ES) into activated carbon (AC) and characterize the AC using Association of Official Analytical Chemists (AOAC) and American Standard for Testing and Materials (ASTM) methods. The AC produced was characterized for: pH, moisture content, volatile matter, ash content, fixed carbon, bulk density and surface area. Surface functional groups and surface morphology were also determined using Fourier Transformed Infrared (FT-IR) and Scanning Electron Microscope (SEM) respectively. The ranges of the following results were achieved for the biomasses: Groundnut shell Activated Carbon (GSAC) and Eggshell Activated Carbon (ESAC) respectively: pH (6.80±0.101−7.80±0.011); moisture content (14.10±0.101−12.90±.110%); volatile matter (9.20±0.112−9.90±0.012%); ash content (8.98±0.111−5.80±0.111%); fixed carbon (67.70±0.010−71.40±110%); bulk density (370.00±0.000−380.00−0.000 g/L); surface area (880.00±0.100−800.00±0.000 m2/g). The agro-wastes have high carbon contents and low inorganic which make them viable adsorbents. FT-IR analysis revealed the presence of oxygen surface complexes such as carbonyls and OH groups on the surface of the ACs in addition to good pore structures from SEM studies revealed that the agro-wastes could be good precursors for ACs production. The overall results showed that the AC produced from the agro-wastes can be optimally used as good and effective adsorbents, thereby ensuring cheaper, readily available and affordable ACs for the treatment of effluent, waste water and used oils.

Sustainable Production of Bioethanol by Zymomonas mobilis and Saccharomyces cerevisiae using Rice Husk and Groundnut Shell as Substrates

Background of Study: Plant waste such as rice husk and groundnut shell are generated in large amounts, these waste presents a tremendous pollution to the environment. Worldwide, these wastes are often simply dumped into landfills and oceans or used as animal feeds. The recovery of food processing wastes as renewable energy sources represents a sustainable option for the substitution of fossil energy in order to minimize environmental damages and to meet energy demands of the growing population.&#x0D; Aim: To produce bioethanol from rice husk and groundnut shell using local strains of Zymomonas mobilis and Saccharomyces cerevisiae.&#x0D; Place and Duration of Study: Conducted at the Microbiology Laboratory of Abubakar Tafawa Balewa University Bauchi, Bauchi state, Nigeria, between April to June, 2021.&#x0D; Methods: Groundnut shell and Rice husk were collected from local milling center. The wastes were powdered, sieved and used as carbon source. Proximate composition of the subsrate was done and the total carbohydrate was determined by difference. The sum of the percentage moisture, ash, crude lipid, crude protein and crude fibre was subtracted from 100. Zymomonas mobilis and Saccharomyces cerevisiae were isolated from rotten sweet oranges and locally fermented beverage (‘kunun-zaki’) respectively by growing them on Malt Yeast Peptone Glucose Agar (MYPGA) after which they were further screened for their ability to tolerate ethanol and they serve as organisms for fermentation. The enzyme α- amylase was used for hydrolysis. The fermented substrates were distilled at 78oC and the distillate was collected as bioethanol in a conical flask. UV-VIS spectrophotometer was used to determine the absorbance of each concentration (0, 0.2, 0.4, 0.6 and 0.8cm3) of reducing sugar content of the hydrolysates and the bioethanol produced by developing a standard curve at a wavelength of 491nm and 588nm respectively. The concentration of reducing sugar and bioethanol was determined using a reference line from the Standard curve.&#x0D; Results: Proximate analysis done shows that rice husk have 70.09% carbohydrates while groundnut shell has 65.09% carbohydrates. Groundnut shell yielded the highest reducing sugar of 5.096%. Rice husk yielded the lowest quantity of reducing sugar with a total yield of 2.962%. Maximum concentration of bioethanol of 0.971% was produced from the combination of Saccharomyces cerevisiae and Zymomonas mobilis from groundnut shell. The lowest concentration of 0.121% of bioethanol was produced when Saccharomyces cerevisiae was used on rice husk hydrolysates. The synergistic relationship of Saccharomyces cerevisiae and Zymomonas mobilis yielded the maximum bioethanol when compared with the yield obtained when the organisms were used singly. Zymomonas mobilis produced highest bioethanol content when the organisms are used single.&#x0D; Conclusion: This study demonstrates the potentiality of local strains of Saccharomyces cerevisiae and Zymomonas mobilis isolated from rotten sweet orange and locally fermented beverage (‘kunun-zaki’) to produce bioethanol by fermenting the rice husk and groundnut shell hydrolysates.

Groundnut Shells as a Potential Feed Supplement for Ruminants on Pastures: A Review

Communal grazing does not offer adequate forage for ruminants throughout the year. This problem is exacerbated during the dry season when grazing is scarce and of poor nutritional quality. Mineral shortages are common in communal grazing environments and yet they are nutritional requirements for optimal development, physiologic functioning and productivity in animals, as well as for cattle growth, reproduction and health. However, the use of groundnut (Arachis hypogea L.) shell (GNS) that are readily available but have no direct nutritional benefit in humans, have not been extensively investigated as a potential source of animal feed. This paper investigates the potential of GNS as feed supplement for ruminants on pasture and its use in other industries. After extracting the seed, the groundnut shell, accounts for roughly 21-29 per cent of the total weight of the nut. Despite the high lignin content of the shell that necessitates adequate processing before use in animal feed, groundnut shell includes 0.50 per cent crude protein, 59.0 per cent crude fiber, 2.50 per cent ash and 4.43 per cent carbs. Sodium (42.00 mg/100 g), potassium (705.11 mg/100 g), magnesium (3.98.00 mg/100 g), calcium (2.28 mg/100 g), iron (6.97 mg/100 g), zinc (3.20 mg/100 g) and phosphorus (10.55 mg/100 g) are all abundant in groundnut shells. In view of this, GNS, a by-product of industrial processing of groundnuts is a rich source of nutrients and can be used to supplement ruminants on pastures during times when pastures are in short supply and of poor quality. Studies are needed to investigate their use to supplement cattle on pasture grazing during times of feed shortage. However, its use as animal feed supplement is likely to face challenges from other industries such as biofuel production.

STUDY ON THE GEOTECHNICAL PROPERTIES OF LATERITIC SOIL STABILIZED WITH BENTONITE AND GROUNDNUT SHELL ASH AS ADMIXTURE FOR CLAY LINER IN WASTE CONTAINMENT

Waste management in Nigeria is characterized by poor landfilling practices in low-lying areas with improper planning of waste dumping. Whenever the soil on site is unfit for a barrier, it is blended with conventional stabilizers, but these additives are costly, hence the need to partially replace them with cheaper materials to achieve the desired results is essential. Consistency limit and engineering properties tests were conducted on the virgin and treated soil specimens. The Bentonite was added at a constant ratio of 6% whilst the groundnut shell ash was increased in the ratio of 0%, 2%, 4%, 6%, 8% and 10%. Samples were prepared at a moulding water content of (-2% ≥ OMC ≤ 4%), adopting BSL and BSH energy levels. Preliminary laboratory test on the natural soil indicated that the soil is A-4(3) and SM according to AASHTO and USCS classification systems, respectively. From the compaction test carried out, it was observed maximum dry density (MDD) increases and optimum moisture content (OMC) decreases upon stepped addition of Groundnut shell ash (GSA). Hydraulic conductivity, volumetric shrinkage strain and UCS values recorded at 6% bentonite/ 6% groundnut shell ash content gave satisfactory results that met the acceptable values of ≤ 1× 10-9 m/s, ≤ 4%, and ≥ 200 kN/m2 for BSL and BSH energy levels, respectively. The overall acceptable range for groundnut shell ash stabilized bentonite-lateritic soil was obtained at 6% bentonite/ 6% groundnut shell ash blend for samples prepared at moulding moisture content of 19.5 – 21.0% and 16.5 – 20.0% respectively. Investigation of leaching capability of groundnut ash into the environment using batch equilibrium test showed that the desorbed values of iron and pH for the optimally modified soil falls within the acceptable values endorsed by the Nigeria industrial standard (NIS) and world health organization (WHO).

Catalytic microwave preheated co-pyrolysis of lignocellulosic biomasses: A study on biofuel production and its characterization

In this present study, microwave pre-treatment has been used for sustainable biofuel production from three different biowastes through catalytic aided co-pyrolysis techniques. The experimental investigations have been carried out to develop biofuel at temperature (350-550℃), heating rate (15-50℃/min) and particle size (0.12–0.38 mm). The resultant biofuels were characterized using TGA, DTA, FE-SEM, FTIR spectroscopy and NMR spectrum. The pyrolysis process of biomasses without and with catalyst resulted in the yield rate of 29–37% and 39–51% respectively. Moreover, the CaO catalytic co-pyrolysis process of pomegranate peel, groundnut shell and palmcone wastes with a ratio of 50:50 at 0.25 mm particle size has resulted in the highest yield rate of 51.6%. The NMR result of bio-oil samples produced hydroxyl group and aliphatics which clearly state the suitability of bio-oils for automotive application. The bio-oil had promising fuel characteristics consisting more energy density (29.1 MJ/kg), less oxygen content and free of nitrogen.

Potential for hydrothermally separated groundnut shell fibers for removal of methylene blue dye

Textile dyes are considered to be hazardous waste for the environment. Treatment with eco-friendly way is the only solution to protect the environment from this hazardous material. The present research focused on the removal of textile dyes with bio adsorbents. This research work aims to extract fibers from waste groundnut shells (GNS) as a bio adsorbent. The efficiency of the obtained fiber mass as an adsorbent was examined over a dye to gauge its adsorbing potential and expulsion. For the purpose stated, Methylene Blue Dye (MBD) was selected as a model dye. The potential capacity of the obtained groundnut shell fibers (GNSF) was studied by optimizing various parameters such as pH, temperature, initial dye concentration, adsorbent dosage, agitation, and contact time in the batch study. The percentage removal of dye achieved by the fibers obtained from the groundnut shell was 99.5% at mixing speed 150 RPM; temperature 25 °C; dye concentration 10 mg/L; adsorbent dosage: 5 mg/L and time 24 h. The extracted fibers and adsorbed fibers were characterized using FTIR, XRD, and SEM analysis to study various properties such as functional group, chemical characteristics, and morphological studies. The obtained results were well fitted in Langmuir isotherm, Freundlich isotherm, and Temkin isotherm models. The Freundlich model fits the best.

Experimental and computational studies on activated Bambara groundnut (Vigna subterranean) hulls for the adsorptive removal of herbicides from aqueous solution

BackgroundThe excessive usage of herbicides to control herbs by farmers has become an issue of interest to the environmentalist due to the threat posed by such act to the ecosystem, and therefore, there is the need to curb such practices. The efficiency of Bambara groundnut shell for the removal of pendimethalin (PE) and paraquat dichloride (PQ) herbicides from aqueous solution was established in this work. The activated carbon was prepared via chemical activation method using trioxonitrate (v) acid by determining its void volume, moisture content, bulk density and Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) methods. Batch adsorption techniques were set to optimize the adsorption parameters such as solution pH, adsorbate concentration, contact time, adsorbent dosage and temperature in order to depict the best optimal conditions for the adsorption process. The adsorption process was examined in terms of its equilibrium data, kinetics, thermodynamics involved in the adsorption process as well as computational quantum chemical parameters evaluation.ResultsThe batch adsorption experiments revealed that the amounts of PE and PQ adsorbed were found to vary with the contact time, adsorbent dosage, pH and initial concentration. The adsorption of PE and PQ decreased with increasing adsorbent dose but increases with increasing initial concentration of the PE and PQ solution. Isotherm studies revealed that the equilibrium data fitted to both Langmuir and Freundlich model with R-squared values of 0.976, 0.993 and 0.909, 0.978 for PE and PQ, respectively, which implied that Langmuir isotherm had a better fit. This was also found to be an indication that the uptake of PE and PQ by ACBGNS occurred through monolayer adsorption on identical homogenous sites. Also, kinetic modeling results obtained showed that the pseudo-second-order model explained the adsorption kinetics of PE and PQ by ACBGNS best, which meant that chemisorption was the slowest step and, thus, the rate determining step. The positive value of ΔH and the positive value of ΔG show the endothermic and spontaneous nature of adsorption of PE and PQ ACBGNS.ConclusionBatch adsorption experiment and characterization of the ACBGNS have indicated that Bambara ground nut shell can be used to produce activated carbon that can be applied effectively for adsorption of PE and PQ from an aqueous solution. Computational studies results obtained from quantum chemical analysis are consistent with the experimental results obtained from this study.