Agricultural Waste Materials Research Articles

Optimization of the California Bearing Ratio of Lateritic Soil Stabilized with Rice Husk Ash using Scheffe’s Method

In a bid to minimize the adverse effects of agricultural waste materials in the environment and also encourage for its optimal usage, this study aims at developing model constants for optimizing the California Bearing Ratio (CBR) of Lateritic Soils stabilized with Rice Husk Ash (RHA) using Scheffe’s method. The study practically involved sampling of the materials, laboratory testing and model formulation. The natural soil was subjected to standardized laboratory testing to determine its index and Engineering properties. The scheffe’s method provided mix ratios for the three mix components (lateritic soil, RHA and water) involved in the mix design. The method also employs the use of second-degree polynomials to generate the model constants. The CBR of the soil was the primary property of the soil considered in the study therefore, a CBR test was conducted on the natural soil and modified soil. The optimization technique carried out gave an optimal mix observed to be of mix ratio 1: 1.70: 0.25 for lateritic soil, RHA and water with a CBR value of 30%. The model formulated was further subjected to validation using the F-test and T-test statistical method and it was found adequate at a confidence level of 95%. Hence, the null hypothesis (H0 ) was adopted. The formulated model being adequate can be used exclusively to predict the CBR of Lateritic soil Stabilized with Rice Husk Ash within the same locality.

Experimental investigation of quaternary blended sustainable concrete along with mix design optimization

The application of pozzolanic materials used either singly or in conjunction with other materials in concrete not only improves the mechanical and durability properties but can provide eco-environmental benefits, as well. This study is an effort to make concrete more sustainable by partially substituting cement with industrial and agricultural waste materials such as fly ash (FA), pumice (Pu) and rice husk ash (RHA) to understand their combined effects on fresh properties, mechanical properties, and sorption of quaternary blended concrete samplings. For this resolve, fifteen different mix proportions of quaternary blends were prepared for evaluating the above-mentioned properties. The maximum values of standard consistency, initial setting time and final setting time were observed to be 38.5%, 162 min and 261 min for C50-F10-R15-P25, C70-F15-R5-P10 and C50-F10-R15-P25, respectively. The compressive and flexural strength of all specimens improved with time. Some specimens showed significant compressive strength and flexural strength gain (about 43% and 57% more than the 28 days values at 120 days, respectively). Similarly, the quaternary blended specimens demonstrated excellent durability, as evident from the lower water intrusion values of the sorption test. The optimized values of mix design constituents as obtained from the response surface methodology approach revealed that a maximum compressive strength of about 44.44 MPa can be obtained if the sand-to-cement ratio (s/c), water-to-cement ratio (w/c) and curing age are 2.5, 0.5 and 90 days, respectively and keeping the amount of FA, RHA and Pu as 50 kg/m3, each.

Production, Optimization and Characterization of Amylase Using Solid State Fermentation Method

Amylases are enzymes produced by a wide range of organisms. The applications of these biomolecules cut across different industries such as detergent, brewing and food industries. <i>Aspergillus flavus</i> has been well documented as one the microbes capable of degrading starch-based agricultural waste materials. This study aimed at optimizing and characterizing amylase produced using agro-waste (potato peels) as a sole carbon source. <i>A. flavus</i> was obtained from the Department of Microbiology laboratory, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria. The fungus was preserved on PDA and stored at 4°C throughout the study period. This was followed by characterization and purification. Preliminary screening result showed that <i>A. flavus</i> had a clear zone of 13.33 mm (diameter of hydrolytic zone) and amylase activity of 545 U/ml. Stability assay revealed that the enzyme was stable at 50°C and 60°C by retaining 91% and 84% residual activities respectively after 4 h of pre-incubation period, while residual activities of 80% and 90% were observed at pH 6.0 and 8.0 respectively. Protein band analysis showed that the amylase from <I>A</I>. <i>flavus</i> had molecular weight of 35 kDa. These results indicated that the amylase produced from <i>A. flavus </i>had good catalytic properties and compared well with those from other known fungi. This study therefore recommends industrial production of amylase from <i>A. flavus</i> using potato peels as a substrate.

Effect of Pyrolysis Temperature on Chemical and Structural Properties of Raw Agricultural Wastes

This study was carried out to assess the effect of charring on chemical and structural properties of raw agricultural wastes at two different temperatures. The agricultural wastes (feather from the poultry unit, maize cob, maize stalk, bamboo, rice straw, cocoa pods, maize husk and used paper from offices) were collected from Teaching and Research Farm, Obafemi Awolowo University (OAU), Ile-Ife, Osun State, Ife excluding the used paper, which was collected from the Academic areas, OAU. The collected waste materials were air-dried, pulverized, ground, and sieved with 2 mm sieve separately. Biochars were produced from raw agricultural wastes at pyrolysis temperatures 400℃ and 450℃. The raw and selected charred agricultural wastes were subjected to chemical and structural analyses. Pyrolysis of the raw materials at the two temperatures led to a significant increase in pH. A significant decrease in organic carbon of all the agricultural waste materials was observed after pyrolysis, a lower C:N was recorded; however, nitrogen content did not change significantly with pyrolysis temperature compared with the raw waste materials. The concentrations of cations like Ca and Mg were unaffected by the pyrolysis temperatures, but significant increase was observed with potassium. The results of FTIR analysis indicated the presence of many surface functional groups in both the raw and charred materials, such as OH, COOH and NH, that could be involved in adsorption and release of plant nutrients in soils, including heavy metals adsorption from soil. However, the intensities of the functional groups were lower in raw agricultural wastes compared with charred agricultural waste. The effect of temperature differences was not significant on the elemental and structural properties; thus, any could be taken as the optimum temperature for effective biochar production. It was concluded that biochar produced from agricultural wastes could be used as liming materials and soil amendments. Also, the presence of carboxylic and phenolic groups in the charred materials will increase the soil cation exchange capacity and improve the nutrient holding capacity of the soil.

Adsorption of chromium (VI) on low-cost adsorbents derived from agricultural waste material: a comparative study and experimental design

ABSTRACT In this study, the Medlar Activated Carbon (MAC) and Cucumis Melo Activated Carbon (CMAC) were used as adsorbents for Cr (VI) removal by adsorption in batch mode from aqueous solutions. The experimental results obtained showed that the percentage of metal elimination increases with the increase of adsorbent dose, contact time and temperature but decreases with increase of initial pH and metal initial concentration. A 24 full factorial experimental design was employed to determine the optimum values and degree of importance of parameters. The process of Cr (VI) adsorption by studied adsorbents is strongly influenced by initial concentration of Cr (VI) and initial pH of the solution. The maximum values of the adsorption yield are obtained at low pH 1.5 (acid medium). The adsorption kinetics follow well the pseudo-second order model, and the external diffusion seems to be the decisive step in the process of adsorption of Cr (VI) ions by the adsorbents studied. The modelling of the isotherms showed that the Langmuir model appears to be the most consistent with the experimental data of Cr (VI) adsorption by the different adsorbents. The maximum adsorption capacity, determined from the Langmuir model at pH 1.5 and 25°C, is 34.12 mg/g for MAC and 54.28 mg/g for CMAC. The thermodynamic parameters of the Cr (VI) adsorption on the biomasses indicate that the process is spontaneous, favourable and endothermic. The values of the activation energy (<7 kJ/mol) indicate that the adsorption is physical in nature.

Recent Advances in Synthesis of Graphite from Agricultural Bio-Waste Material: A Review.

Graphitic carbon is a valuable material that can be utilized in many fields, such as electronics, energy storage and wastewater filtration. Due to the high demand for commercial graphite, an alternative raw material with lower costs that is environmentally friendly has been explored. Amongst these, an agricultural bio-waste material has become an option due to its highly bioactive properties, such as bioavailability, antioxidant, antimicrobial, in vitro and anti-inflammatory properties. In addition, biomass wastes usually have high organic carbon content, which has been discovered by many researchers as an alternative carbon material to produce graphite. However, there are several challenges associated with the graphite production process from biomass waste materials, such as impurities, the processing conditions and production costs. Agricultural bio-waste materials typically contain many volatiles and impurities, which can interfere with the synthesis process and reduce the quality of the graphitic carbon produced. Moreover, the processing conditions required for the synthesis of graphitic carbon from agricultural biomass waste materials are quite challenging to optimize. The temperature, pressure, catalyst used and other parameters must be carefully controlled to ensure that the desired product is obtained. Nevertheless, the use of agricultural biomass waste materials as a raw material for graphitic carbon synthesis can reduce the production costs. Improving the overall cost-effectiveness of this approach depends on many factors, including the availability and cost of the feedstock, the processing costs and the market demand for the final product. Therefore, in this review, the importance of biomass waste utilization is discussed. Various methods of synthesizing graphitic carbon are also reviewed. The discussion ranges from the conversion of biomass waste into carbon-rich feedstocks with different recent advances to the method of synthesis of graphitic carbon. The importance of utilizing agricultural biomass waste and the types of potential biomass waste carbon precursors and their pre-treatment methods are also reviewed. Finally, the gaps found in the previous research are proposed as a future research suggestion. Overall, the synthesis of graphite from agricultural bio-waste materials is a promising area of research, but more work is needed to address the challenges associated with this process and to demonstrate its viability at scale.

Understanding the potential role of precursor content in the geopolymer concrete strength development

A common pozzolanic admixture used by several studies is agricultural waste ashes. An amorphousaluminosilicate substance is knownas pozzolanic admixture, which may not be inherently cementitious but combines with water and calcium hydroxide to produce cementitious substances.As precursors, fly ash and ground-granulated blast furnace slag (GGBS), industrial by-products, have been employed as raw materials in geopolymer concrete. However, a significant prerequisite for the development of geopolymer concrete, aluminosilicate sources are abundant in agricultural waste ashes as well. Therefore, this experimental work aimed to create a geopolymer using industrial waste products and agricultural waste ashes to effectively use readily available and inexpensive agricultural waste materials like rice husk ash (RHA) and bagasse ash (BA). In this study, various geopolymer concrete mixtures with variable levels of precursors (fly ash, GGBS, RHA, and BA) were cast and tested for their 28-day compressive strength and X-ray diffraction (XRD) analysis. Based on the findings of the compressive strength experiments, it is found that addition of RHA and BA significantly improves the compressive strength of the geopolymer concrete. XRD traces of geopolymer concrete blended with RHA and BA revealed that both RHA and BA added geopolymer concrete has denser intermolecular bonding of materials as compared to the fly ash based and GGBS based geopolymer concrete. Additionally, the geopolymer concrete that incorporates RHA has a higher cost-effectiveness than geopolymer concrete that is combined solely with industrial by-products.

Concrete made with partially substitution corn cob ash: A review

The idea of using agricultural and industrial waste materials in concrete helps to develop alternatives for protecting the environment, compensating for the shortage of environmental sources, and resolving the waste dumping issue. Environmental awareness about possible adverse effects has substantially expanded, and, consequently, recycling or utilizing agricultural and industrial waste by-products has become an increasingly desirable option for waste disposal. A review of corn cob ash (CCA) use in the construction industry is provided, and emerging trends in fresh properties, strength properties, durability characteristics, and microstructural properties are evaluated. The results show that adding CCA to concrete is advantageous for waste reduction and sustainable development. Furthermore, the optimum substitution of CCA is important. Although different researcher recommends different optimum substitution of CCA due to different source. However, the typical range of optimum substitution of CCA varies by 5–10% by weight of the binder. Therefore, the review recommends that CCA can be utilized in concrete for up to 10% without any harmful impact on concrete qualities. To close the possible research gap, a thorough investigation of the chemical composition of CCA from a different source and durability factors including alkali-silica reaction, shrinkage, and creep properties must be performed.

Green synthesis and physical properties of crystalline silica engineering nanomaterial from rice husk (agriculture waste) at different annealing temperatures for its varied applications

Crystalline nano silica (SiO2) was synthesized using a cost-effective eco-friendly method from agricultural waste material like rice husk. Polymer nanocomposite has been prepared using the sol-gel technique from crystalline nano silica using PVA as a polymer binder. Thermal analysis measurement is employed to investigate thermal stability. The XRD analysis shows the crystalline nature of silica is revealed to have characteristic peaks of SiO2. The particle size was evaluated using Schererr's formula and found to be in the range of 21–31 nm. FTIR measurement shows the presence of O–Si–O (silane) bond formation. The PL measurement shows broad excitation prominently in the visible region. In the XRD pattern, a major peak of the Nanocomposite is observed at an angular position of 19.5° degree, which is more prominent than that of the PVA with the addition of 0.2 wt percent Nano silica to the PVA composite. SEM provides information on homogeneous distribution. This could be beneficial in terms of higher mechanical qualities as well as multifunctional properties. By hydrogen bonding, the PVA molecules are strongly linked to each SiO2 nanoparticle as measured by FTIR. The stability of materials is confirmed by Zeta Potential and DLS. In the photoluminescence property of SiO2-PVA crystalline Nano silica composite is excited using a radiation wavelength of 200 nm. The indirect bandgap was determined to be 4.28 eV which could be attributed to the 1100 °C annealing temperature. Such materials may be used as a semiconductor material obtained from a direct natural source, rice husk. Thus, in the present research structural, physical, and optical properties of crystalline nano silica and its polymer composite are explored, which leads us to prepare technological grads material from agricultural waste for varied applications including Agriculture to medical science.

A review on the material performance of geopolymer concrete as green building materials

The production of ordinary portland cement (OPC) leads to a significant portion of global CO2 emissions in the atmosphere. Recently, there has been a focus on studying the micro and macro characteristics of geopolymer concrete (GPC) as an alternative to Portland cement concrete (PCC). Due to their superior mechanical properties, environmentally friendly nature, and capability to utilize a variety of wastes as precursors, geopolymers have gained more attention. The primary concern for the construction industry is the material characteristics of the structural components. This review paper examines the physical, mechanical, and durability characteristics of geopolymer concrete made from various industrial and agricultural waste materials high in alumina and silica. Also, the recent advancements in geopolymer concrete and its challenges are discussed in detail. The results of this review indicate that GPC has comparable or superior fresh, mechanical, and durable properties to conventional cement concrete composites. Numerous industrial, municipal, and agricultural wastes can be used to produce structurally sound, environmentally friendly, and durable geopolymer matrices. Therefore, geopolymer concrete is a suitable replacement for traditional cement composites and other building materials.

Combustion characteristics of briquettes made from microwave-assisted co-pyrolysis products of palm shell and LDPE

Briquettes are solids that are generally made from agricultural waste materials. Char briquettes are one of the alternative energies for daily needs. This study used char from palm shell and LDPE microwave-assisted co-pyrolysis at 450 Watts. The briquettes were made from the product of co-pyrolysis of palm shell and Low-Density Polyethylene (LDPE) with variations in the composition of 0:100, 50:50, and 100:0 and pressure of 50 kg/cm2, 100 kg/cm2, 150 kg/cm2, and 200 kg/cm2. In this research, thermogravimetry analysis (TGA) was the method used to determine combustion characteristics. This study aimed to determine the combustion characteristics, including the Initiation Temperature of Fixed Carbon (ITFC), Initiation Temperature of Volatile Matter (ITVM), Peak of weight loss rate Temperature (PT), Activation Energy (Ea), and Mass Loss Rate (MLR). The results showed that the increased briquettes pressure increases the ITVM, ITFC, PT, and EA. The higher LDPE composition in the briquettes decreased the ITVM, ITFC, PT, and Ea, but increased the MLR.

Biogenic Straw Aerogel Thermal Insulation Materials

Biogenic wheat straw is a carbon‐storing building insulation material. However, the enzymatic hydrolysis ratio of its cellulose is relatively low due to the presence of hemicellulose and lignin hindering its thermal insulation performance. Herein, aerogel and straw composites are reported with thermal conductivity of 35 mW m−1 K−1, while high‐cellulose fiber conversion in straw is obtained using a hybrid mechanical and chemical process. Furthermore, it is shown that the in situ cellulose‐reinforced silica aerogel nanocomposites exhibit an optimal thermal conductivity of 32 mW m−1 K−1 using 50 wt% of aerogel. Moreover, the hydrophobic aerogel–cellulose composites show a low density, high porosity (90%), high compression modulus (1.9 MPa), superhydrophobicity, and superior reusability. Herein, a cost‐effective and facile method to manufacture biogenic composites from agriculture waste materials, promising for carbon‐sequestration building insulation applications is provided.

Optimum pretreatment of corn stover ash as an alternative supplementary cementitious material

As sustainable construction practices become more popular, researchers are looking into using readily available and inexpensive agricultural waste materials as a supplementary cementitious material. This study investigates the impact of various pretreatment methods on the chemical composition, crystal structure, morphology, and cost of producing pretreated corn stover ash collected from four different sources in the U.S. This study also evaluates the performance of mortars and pastes containing treated corn stover ash through tests such as compressive strength, flow measurement, calorimetry, and thermal analysis. In addition, thermodynamic modeling is used to predict the phase composition, chemical composition of the pore solution, pH, and electrical resistivity of pastes made with selected pretreated corn stover ashes. The results suggest that acid pretreatment is the most effective and economical method for improving the quality of corn stover ash and that it removes a significant amount of alkalis from the raw material. The simulation of the reaction between cement and the pretreated corn stover ash was confirmed by the experimental results, indicating a marked enhancement in the pozzolanic activity and chemical and physical characteristics of the system.

Statistics-Based Optimization of Cellulase and Xylanase Production by the Endophytic Fungus Talaromyces Funiculosus using Agricultural Waste Materials

Lignocellulosic biomass can be utilized as a low-cost, renewable, and sustainable feedstock for obtaining non-fossil energy sources with low CO2 emission. One of the most promising technologies for producing 2G biofuels is the saccharification of agricultural waste materials with the help of cellulolytic enzymes, followed by yeast fermentation of sugars into cellulosic ethanol. Cellulases are multi-component enzymes involved in the degradation of cellulose, which can synergistically degrade cellulose and includes three major categories: endoglucanase (EC 3.2.1.4), exoglucanase or cellobiohydrolase (EC 3.2.1.91), and β-glucosidase (EC 3.2.1.21). The core enzyme used for the degradation of the xylan skeleton of hemicellulose is endo-β-1,4-xylanase (EC 3.2.1.8). The high cost of enzymes synthesized by fungi is a bottleneck for the production of cellulosic ethanol. Optimization of the nutrient medium composition is an important factor in increasing the production of enzymes and the efficiency of lignocellulosic biomass hydrolysis. The aim of the current study was to optimize the production of cellulolytic and xylanolytic enzymes through cultivation of filamentous fungus Talaromyces funiculosus on low-cost nutrient media with non-pretreated agricultural waste materials. Methods. Filamentous fungus Talaromyces funiculosus was grown on potato-dextrose agar for 10—14 days at 26±2 °С. To obtain the culture filtrate, the fungus was cultivated under submerged conditions in an Erlenmeyer flask for 4 days. The nutrient medium composition was varied according to the factor experiment design. A two-step optimization of the nutrient medium composition was used. A screening experiment with the Plackett-Burman fractional factorial design and response surface methodology with the Box-Behnken design were used to optimize cellulase production. The enzymatic activity was determined by measuring the reduced sugar production after the enzymes hydrolysis with specific substrates: exoglucanase with filter paper, endoglucanase with carboxymethylcellulose, and xylanase with beech wood xylan, using the colorimetric DNS method with glucose or xylose as a standard. The activity of β-glucosidase was determined by the hydrolysis reaction of p-nitrophenyl-β-D-glucopyranoside, which results in the formation of p-nitrophenol, quantified at 410 nm. Results. As a result of experiments with using agricultural waste, including wheat straw, corn stalk, and corn cob as carbon sources of the culture medium, it was shown that T. funiculosus is able to grow and produce cellulase and xylanase on all non-pretreated substrates studied. The two-step sequential optimization of the nutrient medium composition for T. funiculosus cultivation according to the Plackett-Berman and Box-Behnken designs made it possible to increase the activity of cellulolytic and xylanolytic enzymes by 2.4—2.6 times. The optimized cultivation medium does not contain such expensive components as Avicel, peptone, and yeast extract and has the following composition, g/L: corn stalks — 50.0; urea — 0.86; NaNO3 — 1.0; KH2PO4 — 6.0; KCl — 0.25; MgSO4 — 0.25; FeSO4 — 0.01. Conclusions. The studied strain of T. funiculosus produces a lignocellulosic enzyme complex with a high level of β-glucosidase activity when cultivated on an optimized nutrient medium with untreated agricultural waste and is promising for the conversion of lignocellulosic biomass into fermentable sugars.

Utilization of millet husk ash as a supplementary cementitious material in eco-friendly concrete: RSM modelling and optimization

The environment has been greatly impacted by the increase in cement consumption. However, a huge quantity of energy is consumed and large amount of poisonous gases releases into the atmosphere during the cement production, which harms the environment. In order to decrease not only cement manufacturing but also energy usage and to aid in environmental protection, scientists are attempting to introduce agricultural and industrial waste materials with cementitious characteristics. Therefore, millet husk ash is used as supplementary cementitious material (SCM) in the concrete for producing sustainable environmental. The main purpose of this investigation is to check the workability, compressive strength, splitting tensile strength, flexural strength and drying shrinkage of concrete incorporating 0 %, 5 %, 10 %, 15 % and 20 % of MHA as SCM in concrete. A total of 165 concrete samples was made with mix proportion of 1:1.5:3 and cured at ages of 7, 28, and 90 days. The investigational outcomes displayed that there was an improvement in compressive strength, tensile strength, and flexural strength by 11.39 %, 9.80 %, and 9.39 %, correspondingly, at 10 % of MHA replacement of cement. Also, the water absorption reduced as MHA content increased after 28 days. There was also a reduction in drying shrinkage of concrete as the MHA increased after 28 days. Though, the workability is declined as the proportion of MHA increased in concrete. Moreover, the embodied carbon is declined while the content of PC substituted with MHA rises in concrete. In addition, response prediction models were built and validated using ANOVA at a 95 % significance level. R2 values for the models varied from 87.47 to 99.59 percent. The study concludes that the accumulation of 10 % MHA in concrete has a favourable effect on the characteristics of the concrete.

A Scientometric Analysis Review on Agricultural Wastes Used as Building Materials

The rapid urbanization of developed countries and the difficulty in disposing of agricultural wastes have created opportunities for the construction industry to use agricultural wastes. A wide variety of agricultural waste materials are already in use with concrete as substitutes for cement and aggregates, as well as reinforcing materials. This study reviews the available literature published from 1935 to 2022 on agricultural wastes being used as building materials. The research utilizes a bibliographic approach based on the Scopus database. This article retrieves data employing the Scopus database and incorporates 671 articles based on the keywords, agricultural wastes used as building materials. The scientometric analysis is the second step, wherein the patterns of the obtained articles are investigated with various factors such as countries with the most publications, sources that have the most publications, most frequently appearing keywords, and articles with more relevant research works. A summary of the results obtained at various stages of the research is depicted in each phase. Detailed quantitative and qualitative discussions are also conducted to achieve the three main objectives: the summarization of quantitative data, discussion of the existing application, and identification of future research directions. These findings serve the future endeavor of agricultural waste-to-building materials’ incineration academic research. The scientometric review paves the way for academics from various nations to impart novel ideas and information and foster research collaboration.

Effect of high volume tile ceramic wastes on resistance of geopolymer mortars to abrasion and freezing-thawing cycles: Experimental and deep learning modelling

Utilizing industrial and agriculture waste materials to produce a green and sustainable mortar have widely investigated and assessed based on the mechanical and durability properties. Herein, the abrasion and freezing-thawing resistance of fly ash (FA)-ground blast furnace slag (GBFS) based geopolymer mortars incorporating high content of tile ceramic wastes (TCWs) have been evaluated experimentally and mathematically using artificial neural network (ANN). A relatively dilute (4 M) alkaline solution was used to activate the ternary blend. The TCWs was maintained as a relatively large percentage of the total binder, i.e. 50%, 60% and 70%. Once the casting process was complete, curing of the samples was performed at 27 °C. These then underwent testing at day 1, day 3, day 7 and day 28 to provide durability data for various specimen ages. Tests encompassed exposure to abrasion, ability to withstand cyclic freeze-thawing and wet-drying, and permeability to water. Investigations to establish the impact of the high TCWs proportion on the generation of sodium aluminium, calcium aluminium and calcium silicate hydrate (N, C-A-S-H) gels, respectively, included X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. The large percentage of TCWs (70%) generated GPMs that had a minimal effect on the environment and which, by day 28, evidenced a compressive strength above 35 MPa. Augmenting the GBFS and FA content promoted the capacity to withstand freeze-thawing cycles and enhanced durability. Improved performance was also observed in scenarios associated with abrasion resistance. In addition, the proposed models proved their accuracy in which MSE, MAPE, SI were less than 1.93, while R2 of greater than 0.9 confirmed the closeness between predicted and actual results. Substitution of TCWs and FA for GBFS additionally reduced landfill problems of ceramic wastes and achieved the sustainability aims.

Applications of agricultural residue biochars to removal of toxic gases emitted from chemical plants: A review

Crop residues are representative agricultural waste materials, massively generated in the world. However, a large fraction of them is currently being wasted, though they have a high potential to be used as a value-added carbon-rich material. Also, the applications of carbon-rich materials from agricultural waste to industries can have economic benefit because waste-derived carbon materials are considered inexpensive waste materials. In this review, valorization methods for crop residues as carbon-rich materials (i.e., biochars) and their applications to industrial toxic gas removals are discussed. Applications of crop residue biochars to toxic gas removal can have significant environmental benefits and economic feasibility. As such, this review discussed the technical advantages of the use of crop residue biochars as adsorbents for hazardous gaseous pollutants and greenhouse gases (GHGs) stemmed from combustion of fossil fuels and the different refinery processes. Also, the practical benefits from the activation methods in line with the biochar properties were comprehensively discussed. The relationships between the physico-chemical properties of biochars and the removal mechanisms of gaseous pollutants (H2S, SO2, Hg0, and CO2) on biochars were also highlighted in this review study. Porosity controls using physical and chemical activations along with the addition of specific functional groups and metals on biochars have significantly contributed to the enhancement of flue gas adsorption. The adsorption capacity of biochar for each toxic chemical was in the range of 46–76 mg g−1 for H2S, 40–182 mg g−1 for SO2, 80–952 μg g−1 for Hg0, and 82–308 mg g−1 CO2, respectively. This helps to find suitable activation methods for adsorption of the target pollutants. In the last part, the benefits from the use of biochars and the research directions were prospectively provided to make crop residue biochars more practical materials in adsorption of pollutant gases.

Evaluation of pozzolanic activity of ternary blended supplementary cementitious material with rice husk ash and GGBS

The utilization of industrial and agricultural waste materials as supplementary cementitious material in blended cements provides an adequate solution for reducing the greenhouse emission and the environment concerns associated with waste management. Few literatures have been reported on the partial substitution of cement with the blended usage of mineral admixtures such as GGBS and RHA in cement mortars. The effect of blended usage of the mineral admixture as partial replacement of cement are investigated based on the physical and pozzolanic properties of ternary blended cement mortar. An optimal proportion of RHA -GGBS blended supplementary cementitious material is proposed based on strength activity index for utilizing them in ternary blended cement. The blended supplementary cementitious material with 30% rice husk ash and 70% ground granulated blast furnace slag as constituent materials are identified as the optimal proportion for achieving better pozzolanic activity.

A cradle to cradle approach towards remediation of uranium from water using carbonized arecanut husk fiber.

Sustainable materials for remediation of pollutants from water is the need of the hour. In this study two carbonaceous adsorbents prepared through hydrothermal carbonisation and pyrolysis from arecanut husk fiber, an agricultural waste material were used for the adsorption of uranium from water. Batch adsorption data as interpreted using the Langmuir model showed adsorption capacities of 250 mg g-1 and 200 mg g-1 respectively at pH 6 for the hydrochar (AHFC) and the pyrochar (AHFT) exceeding that reported for most of the unmodified biochars. The adsorption followed pseudo-second order kinetics and was exothermic in nature. The high selectivity and excellent removal efficiencies on application to environmental ground water samples and good regeneration capacity make these sorbents promising eco-friendly materials for uranium remediation from water.