scholarly journals A study on the utilization of rice husk as a biosorbent material for Cr (VI) removal from industrial effluent

2022 ◽  
Vol 20 (2) ◽  
pp. 321-327
Author(s):  
Aniqa Naeem ◽  
Rida Batool
Keyword(s):  
Citric Acid ◽  
Functional Groups ◽  
Rice Husk ◽  
High Efficiency ◽  
Agricultural Waste ◽  
Industrial Effluent ◽  
Industrial Effluents ◽  
Physical Factors ◽  
Dihydrogen Phosphate ◽  
Bacterial Strains

Purpose: To study Cr (VI) removal from waste water using chromium-resistant bacterial strains in combination with rice husk. Methods: Two strains of Exiguobacterium sp. resistant to chromium (VI) were applied in the present work. Rice husk (RH) was used as an agricultural waste for Cr (VI) removal. The elimination of Cr from the husk was chemically facilitated using hydrochloric, sulphuric and citric acids, as well as formaldehyde and potassium dihydrogen phosphate Investigation of optimum physical factors such as pH, temperature, shaking speed and biomass concentration on Cr (VI) removal was carried out using citric acid-processed rice husk alone, and in combination of bacterial strains. Fourier transform infra-red (FTIR) spectroscopy was performed to determine the contributions of different functional groups involved in Cr (VI) binding. Scanning electron microscopy (SEM) of treated and untreated RH was also performed. Results: Citric acid-processed RH was most effective in the removal of chromate (97.3 %). The two bacterial strains combined with rice husk proved highly efficient in Cr (VI) removal from sterile and non-sterile industrial effluents. FTIR spectra showed the involvement of esters, amines and aliphatic functional groups in Cr (VI) binding, while SEM displayed the damaging effects of Cr (VI) on the surface of RH; however, bacterial inoculation minimized the damage. Conclusion: Exopolysaccharides from Exiguobacterium strains and citric acid-processed rice husk demonstrated high efficiency for Cr (VI) removal. Hence, RH with these bacterial strains are potential biosorbents for control of heavy metal contamination arising from industrial effluents.

scholarly journals Analysis of Strength Development and Soil–Water Characteristics of Rice Husk Ash–Lime Stabilized Soft Soil

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3873 ◽  
Author(s):  
Jiang ◽  
Huang ◽  
Ma ◽  
Luo
Keyword(s):  
Soil Water ◽  
Rice Husk ◽  
High Efficiency ◽  
Rice Husk Ash ◽  
Agricultural Waste ◽  
Soft Soil ◽  
Strength Development ◽  
Water Characteristics ◽  
Stabilized Soil ◽  
Curing Agents

With increased awareness of environmental protection, the output of traditional curing agents such as cement and lime is less and less, so it is urgent to develop new curing agents with high efficiency and environmental benefits. Thus, this study aims at investigating the application of rice husk ash (RHA) from agricultural waste to the soft soil stabilization. A series of tests are conducted to analyze the strength development process and soil–water characteristics of rice husk ash–lime (RHA–lime) stabilized soils. The results of the strength tests showed that by increasing the content of RHA, the unconfined compressive strength (UCS) and splitting strength of stabilized soils increased first and then decreased. The effective shear strength indexes of the three soil types (soft soil, lime-stabilized soil, and RHA–lime soil) are measured and compared. It is found that RHA can effectively improve the shear resistance and water resistance of stabilized soil. The results of methylene blue test demonstrated that RHA can also promote the reduction of the specific surface area and swelling potential energy of lime-stabilized soil. In addition, the influence of RHA on mineral composition and morphology change in stabilized soils is studied at the microscopic level. The X-ray diffraction tests and scanning electron microscope (SEM) tests showed that strength development and change of soil–water properties of RHA–lime stabilized soil are attributed to enhanced cohesion by cementation and pores filling with agglomerated mineral.

scholarly journals Citric acid leaching process for removal of iron (Fe) from rice husk

2021 ◽  
Vol 2080 (1) ◽  
pp. 012016
Author(s):  
Faizul Che Pa ◽  
Abdullah Chik ◽  
Hasan Zuhudi Abdullah
Keyword(s):  
Citric Acid ◽  
Rice Husk ◽  
Agricultural Waste ◽  
Combustion Process ◽  
Acid Leaching ◽  
Earth Metal ◽  
Solution Temperature ◽  
Leaching Process ◽  
Stirring Time ◽  
High Level

Abstract Rice husk containing the highest amount composition of silica (SiO2) compared with other agricultural waste. With such a large availability of rice husk, it becomes economical to industrial by the implementation concept of sustainability beside decompose the rice rusk into ash. The extraction of silica and elimination of metallic element, such as iron (Fe) from rice husk (RH) was treated by leaching process. With this, the RH can be utilized to produce various types of useful renewable resources such as silica (SiO2). Using the organic acid as leaching solution is more eco-friendly instead using the inorganic acid that classified as very dangerous chemical due to the high level of hazard. The treated and untreated rice husk ash characterizes using scanning electron microscopy and X-ray diffraction spectroscopy. The morphology of treated rice husk shows the tubular aggregate due to the presence of alkaline earth metal such as Ca and Mg. Under the optimum condition with 90 °C solution temperature, 60 minutes stirring time, 3% of citric acid and calcination temperature of 800 °C for 3 hours, amorphous silica with more than 78% was prepared via citric acid leaching treatment and combustion process.

Removal of Iron (Fe) in Rice Husk via Citric Acid Leaching Treatment

2016 ◽  
Vol 857 ◽  
pp. 540-546
Author(s):  
Nur Haslinda Mohamed Muzni ◽  
Noorina Hidayu Jamil ◽  
Cheow Keat Yeoh
Keyword(s):  
Citric Acid ◽  
Acid Concentration ◽  
Rice Husk ◽  
Agricultural Waste ◽  
Acid Leaching ◽  
Industrial Applications ◽  
Solution Temperature ◽  
Process Conditions ◽  
Optimum Conditions ◽  
Stirring Time

Rice husk (RH) is an agricultural waste which has been utilized as useful renewable resources to produce energy with high-purity silica (SiO2) contents. With such a large availability of rice husk, it becomes economical to industrial applications. This paper was study about the removal of iron from rice husk in aqueous citric acid by using acid leaching treatment. The parameters chosen were reaction temperature, stirring speed, acid concentration and stirring time. The optimum conditions for the maximum removal of 0.14% of iron with citric acid leaching treatment were observed at solution temperature of 70°C; thermostat magnetic stirrer hotplate, 150 W; acid concentration 0.1M-1.0M; stirring time 6h-12h. This method resulted the removal efficiency of iron increasing considerably with the increasing leach C2H7O8 acid concentration. The optimization of the process conditions of the citric acid leaching treatment under the optimum conditions with 6h of stirring time and acid concentration of 1.0M were conducted to remove the metallic impurities of Fe from husks and shows remarkable result.

Physiochemical characterization of agricultural waste biochars for partial cement replacement

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Andrea Nana Ofori-Boadu ◽  
DeAndria Bryant ◽  
Christian Bock-Hyeng ◽  
Zerihun Assefa ◽  
Frederick Aryeetey ◽  
...  
Keyword(s):  
Water Absorption ◽  
Functional Groups ◽  
Rice Husk ◽  
Agricultural Waste ◽  
Surface Functional Groups ◽  
Cement Pastes ◽  
Physiochemical Properties ◽  
Content Type ◽  
Cement Replacement ◽  
Partial Cement Replacement

PurposeThe purpose of this study is to explore the feasibility of utilizing agricultural (almond shell, rice husk and wood) waste biochars for partial cement replacement by evaluating the relationships between the physiochemical properties of biochars and the early-age characteristics of cement pastes.Design/methodology/approachBiochars are prepared through the thermal decomposition of biomass in an inert atmosphere. Using varying percentages, biochars are used to replace ordinary Portland cement (OPC) in cement pastes at a water/binder ratio of 0.35. Characterization methods include XPS, FTIR, SEM, TGA, BET, Raman, loss-on-ignition, setting, compression and water absorption tests.FindingsAccelerated setting in biochar-modified cement pastes is attributed to chemical interactions between surface functional groups of biochars and calcium cations from OPC, leading to the early development of metal carboxylate and alkyne salts, alongside the typical calcium-silicate-hydrate (C-S-H). Also, metal chlorides such as calcium chlorides in biochars contribute to the accelerate setting in pastes. Lower compression strength and higher water absorption result from weakened microstructure due to poor C-S-H development as the high carbon content in biochars reduces water available for optimum C-S-H hydration. Amorphous silica contributes to strength development in pastes through pozzolanic interactions. With its optimal physiochemical properties, rice-husk biochars are best suited for cement replacement.Research limitations/implicationsWhile biochar parent material properties have an impact on biochar properties, these are not investigated in this study. Additional investigations will be conducted in the future.Practical implicationsCarbon/silicon ratio, oxygen/carbon ratio, alkali and alkaline metal content, chlorine content, carboxylic and alkyne surface functional groups and surface areas of biochars may be used to estimate biochar suitability for cement replacement. Biochars with chlorides and reactive functional groups such as C=C and COOH demonstrate potential for concrete accelerator applications. Such applications will speed up the construction of concrete structures and reduce overall construction time and related costs.Social implicationsReductions in OPC production and agricultural waste deterioration will slow down the progression of negative environmental and human health impacts. Also, agricultural, manufacturing and construction employment opportunities will improve the quality of life in agricultural communities.Originality/valueEmpirical findings advance research and practice toward optimum utilization of biomass in cement-based materials.

scholarly journals Study and Use of Rice Husk Ash as a Source of Aluminosilicate in Refractory Coating

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3440
Author(s):  
Mohd Na’im Abdullah ◽  
Mazli Mustapha ◽  
Nabihah Sallih ◽  
Azlan Ahmad ◽  
Faizal Mustapha ◽  
...  
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Agricultural Waste ◽  
Fire Retardant ◽  
Sem Analysis ◽  
Refractory Coating ◽  
Alkyd Paint ◽  
Passive Fire Protection ◽  
In Fire ◽  
Geopolymer Binder

The utilisation of rice husk ash (RHA) as an aluminosilicate source in fire-resistant coating could reduce environmental pollution and can turn agricultural waste into industrial wealth. The overall objective of this research is to develop a rice-husk-ash-based geopolymer binder (GB) fire-retardant additive (FR) for alkyd paint. Response surface methodology (RSM) was used to design the experiments work, on the ratio of RHA-based GB to alkyd paint. The microstructure behaviour and material characterisation of the coating samples were studied through SEM analysis. The optimal RHA-based GB FR additive was formulated at 50% wt. FR and 82.628% wt. paint. This formulation showed the result of 270 s to reach 200 °C and 276 °C temperature at equilibrium for thermal properties. Furthermore, it was observed that the increased contents of RHA showed an increment in terms of the total and open porosities and rough surfaces, in which the number of pores on the coating surface plays an important role in the formation of the intumescent char layer. By developing the optimum RHA-based GB to paint formulation, the coating may potentially improve building fire safety through passive fire protection.

scholarly journals Ionic Liquid-Assisted Synthesis of Ag3PO4 Spheres for Boosting Photodegradation Activity under Visible Light

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 788
Author(s):  
Beibei Zhang ◽  
Lu Zhang ◽  
Yulong Zhang ◽  
Chao Liu ◽  
Jiexiang Xia ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Visible Light ◽  
High Efficiency ◽  
Chemical Precipitation ◽  
Active Species ◽  
Precipitation Method ◽  
Dihydrogen Phosphate ◽  
Xrd Pattern ◽  
Simple Chemical ◽  
Visible Light Driven

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.

scholarly journals Desulfurization and Denitrification Performance of Modified Rice Husk Ash-Carbide Slag Absorbent

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 68
Author(s):  
Yali Wang ◽  
Xiaoning Han ◽  
Meina Chen ◽  
Suping Cui ◽  
Xiaoyu Ma ◽  
...  
Keyword(s):  
Functional Groups ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Research Direction ◽  
Cement Industry ◽  
Hydration Process ◽  
Air Pollution Control ◽  
Large Area ◽  
Carbide Slag ◽  
High Investment

In the cement industry, SO2 and NOx are generally removed separately. There are many problems, such as large area, high investment cost, secondary pollution and so on. Desulfurization and denitrification technology have become a frontier research direction in the field of air pollution control. In this paper, rice husk ash and carbide slag were compounded and modified to prepare modified rice husk ash-carbide slag composite absorbent, and its desulfurization and denitrification performance and mechanism were studied. The results showed that the NO conversion and SO2 conversion of the modified rice husk ash-carbide slag composite absorbent increased by 44% and 2%, respectively, at 700 °C. Fibrous calcium silicate and calcium silicoaluminate hydrates were formed during the hydration process, which made the specific surface area of the absorbent larger and provided more reactive sites. The hydration process increases the content of oxygen-containing functional groups, decreases the hydroxyl/ether C–O functional groups, and increases the content of carboxyl–COO functional groups are conducive to the denitrification reaction.

scholarly journals Sustainable Panels Made with Industrial and Agricultural Waste: Thermal and Environmental Critical Analysis of the Experimental Results

2021 ◽  
Vol 11 (2) ◽  
pp. 494
Author(s):  
Paola Ricciardi ◽  
Elisa Belloni ◽  
Francesca Merli ◽  
Cinzia Buratti
Keyword(s):  
Thermal Conductivity ◽  
Life Cycle ◽  
Rice Husk ◽  
Agricultural Waste ◽  
Embodied Energy ◽  
Waste Materials ◽  
Impact Reduction ◽  
Combined Solution ◽  
Order Of Magnitude ◽  
Recycled Waste

Recycled waste materials obtained from industrial and agricultural processes are becoming promising thermal and acoustic insulating solutions in building applications; their use can play an important role in the environmental impact reduction. The aim of the present paper is the evaluation of the thermal performance of recycled waste panels consisting of cork scraps, rice husk, coffee chaff, and end-life granulated tires, glued in different weight ratios and pressed. Six panels obtained from the mixing of these waste materials were fabricated and analyzed. In particular, the scope is the selection of the best compromise solutions from the thermal and environmental points of view. To this aim, thermal resistances were measured in laboratory and a Life Cycle Assessment (LCA) analysis was carried out for each panel; a cross-comparative examination was performed in order to optimize their properties and find the best panels solutions to be assembled in the future. Life Cycle Analysis was carried out in terms of primary Embodied Energy and Greenhouse Gas Emissions, considering a ‘‘cradle-to-gate” approach. The obtained thermal conductivities varied in the 0.055 to 0.135 W/mK range, in the same order of magnitude of many traditional systems. The best thermal results were obtained for the panels made of granulated cork, rice husk, and coffee chaff in this order. The rubber granulate showed higher values of the thermal conductivity (about 0.15 W/mK); a very interesting combined solution was the panel composed of cork (60%), rice husk (20%), and coffee chaff (20%), with a thermal conductivity of 0.08 W/mK and a Global Warming Potential of only 2.6 kg CO2eq/m2. Considering the Embodied Energy (CED), the best solution is a panel composed of 56% of cork and 44% of coffee chaff (minimum CED and thermal conductivity).

Biosorption of Cadmium onto Pseudomonas fluorescens: Application of Isotherm and Kinetic Models

2010 ◽  
Vol 171-172 ◽  
pp. 49-52 ◽  
Author(s):  
Chang Li Yu ◽  
Zhi Peng Lu ◽  
Fa Zhi Ge ◽  
Er Li Zhao
Keyword(s):  
Pseudomonas Fluorescens ◽  
Functional Groups ◽  
Metal Ion ◽  
Freundlich Isotherm ◽  
Industrial Effluents ◽  
Rate Equations ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Kinetics Of Adsorption ◽  
Isotherm And Kinetic Models

The present study was undertaken to evaluate the feasibility of Pseudomonas fluorescens biomass for the removal of cadmium ions from aqueous solutions. Batch experiments were performed to study the adsorption of cadmium on pH, Pseudomonas fluorescens biomass adsorbent with respect to initial Cd(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Cd(II) was 66.25 mg/g (pH 5.0 and 5 g/L biomass dose). Kinetics of adsorption followed second-order rate equations. The FTIR results of Pseudomonas fluorescens biomass showed that biomass has different functional groups and these functional groups are able to react with metal ion in aqueous solution. The results of the present study suggest that Pseudomonas fluorescens biomass can be used beneficially in treating industrial effluents containing heavy metal ions.

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

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