scholarly journals Adsorption of Se(IV) in aqueous solution by zeolites synthesized from fly ashes with different compositions

2019 ◽  
Vol 9 (4) ◽  
pp. 506-519
Author(s):  
Xiao Zhang ◽  
Xinyuan Li ◽  
Fan Zhang ◽  
Shaohao Peng ◽  
Sadam Hussain Tumrani ◽  
...  
Keyword(s):  
Fly Ash ◽  
Contact Time ◽  
High Capacity ◽  
Freundlich Isotherm ◽  
Fly Ashes ◽  
Order Model ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Equilibrium Data ◽  
Pseudo Second Order

Abstract Low-calcium fly ash (LC-F) and high-calcium fly ash (HC-F) were used to synthesize corresponding zeolites (LC-Z and HC-Z), then for adsorption of Se(IV) in water. The results showed that c zeolites can effectively adsorb Se(IV). The optimal adsorption conditions were set at contact time = 360 min; pH = 2.0; the amount of adsorbent = 5.0 g·L−1; temperature = 25 °C; initial Se(IV) concentration = 10 mg·L−1. The removal efficiency of HC-Z was higher than the LC-Z after it had fully reacted because the specific surface area (SSA) of HC-Z was higher than LC-Z. The adsorption kinetics model of Se(IV) uptake by HC-Z followed the pseudo-second-order model. The Freundlich isotherm model agreed better with the equilibrium data for HC-Z and LC-Z. The maximum Se(IV) adsorption capacity was 4.16 mg/g for the HC-Z and 3.93 mg/g for the LC-Z. For the coexisting anions, barely affected Se(IV) removal, while significant affected it. Regenerated zeolites still had high capacity for Se(IV) removal. In conclusion, zeolites synthesized from fly ashes are a promising material for adsorbing Se(IV) from wastewater, and selenium-loaded zeolite has the potential to be used as a Se fertilizer to release selenium in Se-deficient areas.

scholarly journals Removal of Methyl Orange from Aqueous Solutions by Adsorption Using Corn Leaves as Adsorbent Material

2019 ◽  
Vol 25 (4) ◽  
pp. 55-69
Author(s):  
Omar Hisham Fadhil ◽  
Mohammed Y. Eisa
Keyword(s):  
Methyl Orange ◽  
Contact Time ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Order Model ◽  
Several Variables ◽  
Adsorption Data ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

A comparative study was done on the adsorption of methyl orange dye (MO) using non-activated and activated corn leaves with hydrochloric acid as an adsorbent material. Scanning electron microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR) were utilized to specify the properties of adsorbent material. The effect of several variables (pH, initial dye concentration, temperature, amount of adsorbent and contact time) on the removal efficiency was studied and the results indicated that the adsorption efficiency increases with the increase in the concentration of dye, adsorbent dosage and contact time, while inversely proportional to the increase in pH and temperature for both the treated and untreated corn leaves. The equilibrium data is best fitted to Freundlich isotherm for untreated adsorbent, while Langmuir isotherm show best agreement with the data when the treated adsorbent is used. The rate of adsorption was found to follow the pseudo first order kinetic model (PFO) when non-activated adsorbent is used, while the pseudo second order model (PSO) is fitted to the adsorption data using activated adsorbent.  

scholarly journals Durability of blended cement against sodium sulphate attack and alkali-silica reaction

2021 ◽  
Author(s):  
Giri Raj Adhikari
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Alkali Silica Reaction ◽  
Sulphate Attack ◽  
Ternary Blends ◽  
Replacement Level ◽  
Fly Ashes ◽  
Study Results ◽  
High Calcium ◽  
High Calcium Fly Ash

Blended cements were studied for their efficacy against sulphate attack and alkali-silica reaction using six different types of fly ashes, a slag, a silica fume and four types of General Use Portland cement of different alkalinity. The study results showed that low calcium fly ash, silica fume and ground granulated blast furnace slag enhanced the sulphate resistance of cement with increased efficacy with the increase in the replacement level. However, slag and silica fume, especially at low replacement levels, exhibited increased rate of expansion beyond the age of 78 weeks. On the contrary, high calcium fly ashes showed reduced resistance to sulphate attack with no clear trend between the replacement level and expansion. Ternary blends consisting of silica fume, particulary in the amount of 5%, high calcium fly ashes and General Use (GU) cement provided high sulphate resistance, which was attributable to reduced permeability. In the same way, some of ternary blends consisting of slag, high calcium fly ash and GU cement improved sulphate resistance. Pre-blending optimum amount of gypsum with high calcium fly ash enhanced the latter's resistance to sulphate attack by producing more ettringite at the early stage of hydration. In the context of alkali-silica reaction permeability was found to be a contributing factor to the results of the accelerated mortar bar test. High-alkali, high-calcium fly ash was found to worsen the alkali silica reaction when used in concrete containing some reactive aggregates. Ternary blend of slag with high calcium fly ash was found to produce promising results in terms of counteracting alkali-silica reaction.

Adsorption of Methylene Blue on Modified Bentonite

2013 ◽  
Vol 726-731 ◽  
pp. 2380-2383
Author(s):  
Li Xia Li ◽  
Xin Dong Zhai
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Adsorption Kinetics ◽  
Freundlich Isotherm ◽  
Batch Process ◽  
Experimental Results ◽  
Order Model ◽  
Modified Bentonite ◽  
Equilibrium Data ◽  
Pseudo Second Order

Modified bentonite was used as adsorbent for the methylene blue adsorption in a batch process. Experimental results show that the adsorption kinetics is well described by pseudo-second-order model and the equilibrium data was better represented by the Freundlich isotherm model. The results revealed that the modified bentonite has the potential to be used as a good adsorbent for the removal of methylene blue from aqueous solutions.

Stabilization of Drilling Fluid Waste with Fly Ash

1986 ◽  
Vol 86 ◽  
Author(s):  
George M. Deeley ◽  
Larry W. Canter ◽  
Joakim G. Laguros
Keyword(s):  
Fly Ash ◽  
Caustic Soda ◽  
Drilling Fluid ◽  
Drilling Mud ◽  
Fly Ashes ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Water Based ◽  
Land Disposal ◽  
Drilling Muds

Water based drilling muds typically contain clays, barite, lime, caustic soda and other chemicals, such as polymers. Land disposal of these wastes raises the possibility of groundwater pollution which can be abated if the waste is stabilized either by chemical reaction or by solidification through some form of cementation. Many ASTM high-calcium (Class C) fly ashes are cementitious and thus may be useful in stabilization of drilling mud. The basic idea is to stabilize the clay-containing muds using the model of soil and roadbed stabilization with high-calcium fly ash [1]. Fly ash that is not utilized is considered to be a solid waste, so this application would would actually constitute codisposal of two wastes.

scholarly journals The Application of Monkey Cola Pericarp (Cola lepidota) in the Removal of Toluene from Aqueous Medium

2020 ◽  
pp. 53-67
Author(s):  
C. Obi ◽  
N. C. Ngobiri ◽  
L. C. Agbaka ◽  
M. U. Ibezim-Ezeani
Keyword(s):  
Aqueous Medium ◽  
Contact Time ◽  
Second Order ◽  
Phytochemical Screening ◽  
Order Model ◽  
Initial Concentration ◽  
First Order ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Pseudo First Order

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied. The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.

Adsorption of 2,4-Dichlorophenol on Meta-Aramid/Poly (acylic Acid) Composite Nanofibrous Membranes

2012 ◽  
Vol 610-613 ◽  
pp. 551-555 ◽  
Author(s):  
Qi Jun Zhou ◽  
Ran Xu
Keyword(s):  
Adsorption Capacity ◽  
Contact Time ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Acidic Ph ◽  
Order Model ◽  
Electrospinning Method ◽  
Pseudo Second Order ◽  
Equilibrium Adsorption Capacity ◽  
Nanofibrous Membranes

Meta-aramid/poly (acylic acid) (PMIA/PAA) composite nanofibrous membranes with diameter between 50-100 nm have been fabricated by electrospinning method. The effect of contact time, temperature, pH and concentration of 2,4-dichlorophenol on the adsorption capacity of the membranes were investigated. The equilibrium adsorption capacity of 2,4-dichlorophenol on PMIA/PAA nanofibrous membranes is 251.61 mg/g. Acidic pH was favorable for the 2,4-dichlorophenol adsorption. Its desorption rate reached 74% in 45 min. After five regeneration cycles, the removal rate of 2,4-dichlorophenol still maintained above 65%. The adsorption of 2,4-dichlorophenol on the membranes fit the Freundlich isotherm model best. Its adsorption kinetics followed a pseudo-second-order model.

Fuchsine Adsorption from Aqueous Solution by Epichlorohydrin Crosslinked Peanut Husk

2012 ◽  
Vol 549 ◽  
pp. 362-365 ◽  
Author(s):  
Ying Hua Song ◽  
Sheng Ming Chen ◽  
Jian Min Ren ◽  
Yuan Gao ◽  
Hui Xu
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Freundlich Isotherm ◽  
Order Model ◽  
Isotherm Equation ◽  
Thermodynamic Constants ◽  
Pseudo Second Order ◽  
Uptake Studies

The adsorption of fuchsine by peanut husk, which was crosslinked by epichlorohydrin was studied with variation in the parameters of contact time, pH, initial fuchsine concentration and temperature. They were used for equilibrium adsorption uptake studies with fuchsine. The results indicate that adsorption equilibrium could be well described by both the Langmuir and the Freundlich isotherm equation. The adsorption followed the pseudo-second order model. The thermodynamic constants of the adsorption process were also evaluated, which suggest an endothermic adsorption process which runs spontaneously.

scholarly journals Durability of blended cement against sodium sulphate attack and alkali-silica reaction

2021 ◽  
Author(s):  
Giri Raj Adhikari
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Alkali Silica Reaction ◽  
Sulphate Attack ◽  
Ternary Blends ◽  
Replacement Level ◽  
Fly Ashes ◽  
Study Results ◽  
High Calcium ◽  
High Calcium Fly Ash

Blended cements were studied for their efficacy against sulphate attack and alkali-silica reaction using six different types of fly ashes, a slag, a silica fume and four types of General Use Portland cement of different alkalinity. The study results showed that low calcium fly ash, silica fume and ground granulated blast furnace slag enhanced the sulphate resistance of cement with increased efficacy with the increase in the replacement level. However, slag and silica fume, especially at low replacement levels, exhibited increased rate of expansion beyond the age of 78 weeks. On the contrary, high calcium fly ashes showed reduced resistance to sulphate attack with no clear trend between the replacement level and expansion. Ternary blends consisting of silica fume, particulary in the amount of 5%, high calcium fly ashes and General Use (GU) cement provided high sulphate resistance, which was attributable to reduced permeability. In the same way, some of ternary blends consisting of slag, high calcium fly ash and GU cement improved sulphate resistance. Pre-blending optimum amount of gypsum with high calcium fly ash enhanced the latter's resistance to sulphate attack by producing more ettringite at the early stage of hydration. In the context of alkali-silica reaction permeability was found to be a contributing factor to the results of the accelerated mortar bar test. High-alkali, high-calcium fly ash was found to worsen the alkali silica reaction when used in concrete containing some reactive aggregates. Ternary blend of slag with high calcium fly ash was found to produce promising results in terms of counteracting alkali-silica reaction.

Removal of Organic Contaminants from Textile Wastewater by Adsorption on Natural Biosorbent

2020 ◽  
Vol 1002 ◽  
pp. 489-497
Author(s):  
Zainab Hussain ◽  
Zeyad Fadhil ◽  
Sameer Kareem ◽  
Salam Mohammed ◽  
Emad Yousif
Keyword(s):  
Experimental Data ◽  
Organic Contaminants ◽  
Contact Time ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Textile Wastewater ◽  
Order Model ◽  
Multiple Factors ◽  
Pseudo Second Order ◽  
Adsorbent Dose

In the present study, removal of safranin dye from water bodies was investigated using natural biosorbent (Thyme leaves (TEL)). The influence of multiple factors such as as contact time (15 – 105 mins), adsorbent dose (25 to 350) mg/l , adsorbate dose (5 to 40)mg\L, and temperature (25 to 55)o C were taken for investigation. The adsorption isotherms were described by utilized Langmuir, Freundlich and Dubnin-Radushkevich models, Freundlich isotherm model found to be best suited with experimental data out of 3 isotherm The adsorption process followed pseudo second order model.

scholarly journals Utilization of Cactus Peel as Biosorbent for the Removal of Reactive Dyes from Textile Dye Effluents

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Mebrahtu Gebrezgiher ◽  
Zebene Kiflie
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Freundlich Isotherm ◽  
Textile Dye ◽  
Order Model ◽  
Solution Ph ◽  
Biosorption Process ◽  
Good Potential ◽  
Pseudo Second Order ◽  
Red Dye

Textile industries generate large quantities of dye containing wastewater which pose a serious environmental problem. Currently, biosorbents have become desirable for the removal of dyes from textile effluents. In this study, batch experiments were conducted to investigate the biosorption characteristics of cactus peel on the removal of reactive red dye from aqueous solutions. The effects of solution pH, biosorbent dosage, contact time, and initial concentration were studied. The interaction effects of process variables were analysed using response surface methodology. The results showed that removal efficiency increased as initial dye concentration and solution pH decreased and as biosorbent dosage and contact time increased. The highest removal efficiency (99.43%) was achieved at solution pH, initial dye concentration, biosorbent dose, and contact time of 3.0, 40 mg/l, 6 g, and 120 min, respectively. From regression analysis, the Langmuir isotherm was found to better (R2 = 0.9935) represent the biosorption process as compared with the Freundlich isotherm (R2 = 0.9722). Similarly, the pseudo-second-order model was seen to represent very well the biosorption kinetics. The results show that cactus peel has good potential for the removal of reactive red dye.

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