scholarly journals Magnetic rice husk ash 'cleanser' as efficient methylene blue adsorbent

2019 ◽  
Vol 25 (5) ◽  
pp. 685-692 ◽  
Author(s):  
Chosel P. Lawagon ◽  
Ramiro Emerson C. Amon
Keyword(s):  
Environmental Concern ◽  
The Philippines ◽  
Rice Husks ◽  
Feed Concentration ◽  
Solution Ph ◽  
Pseudo Second Order ◽  
Rice Husks Ash ◽  
Wet Market ◽  
Solid Liquid ◽  
Powdered Form

Burning of agricultural residues has been a prevalent cause of environmental concern especially in developing countries. In the Philippines, rice husks are usually burned in open air and either usually left in the field or rarely collected to be sold in the wet market as a cleanser. Hence in this study, an alternative use of this burning residue (rice husks ash, RHA) for removal of dyes from aqueous solutions was explored. Yet, its applications in real wastewater will be difficult in its pristine powdered form. Therefore, the RHA was functionalized with Fe<sub>3</sub>O<sub>4</sub> to become inherently magnetic (MRHA), providing relative ease in handling. The RHA used was obtained from the local markets of Davao City, Philippines. Systematic adsorption studies on the effects of contact time, solution pH, solid/liquid ratio, and feed concentration were conducted. MB adsorption was Langmuir-type and followed a pseudo-second-order rate model. Its adsorption rate is significantly fast (<i>t</i> = 10 min, <i>k</i><sub>2</sub> = 0.015 g mg<sup>-1</sup> min<sup>-1</sup>) with high <i>q<sub>m</sub></i> (150.5 mg g<sup>-1</sup>). MRHA was highly stable and reusable (> 10 cycles) demonstrating its high potential as an economical alternative for treatment of dye contaminated wastewater.

Removal of fluoride from aqueous solution by adsorption onto Kanuma mud

2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Solution Ph ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.

scholarly journals Green Synthesis of A Novel MXene–CS Composite Applied in Treatment of Cr(VI) Contaminated Aqueous Solution

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 524
Author(s):  
Hongyou Wan ◽  
Lan Nan ◽  
Huikai Geng ◽  
Wei Zhang ◽  
Huanhuan Shi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Environmental Concern ◽  
Maximum Adsorption Capacity ◽  
Aqueous Environment ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Xrd Patterns

The considerable amount of Cr(VI) pollutants in the aqueous environment is a significant environmental concern that cannot be ignored. A series of novel Mxene–CS inorganic–organic composite nanomaterials synthesized by using the solution reaction method was applied to treat the Cr(VI) contaminated water. The Mxene–CS composites were characterized through SEM (scanning electron microscope), XRD (X–ray diffraction), XPS (X–ray photoelectron spectroscopy), and FTIR (Fourier transform infrared). The XRD patterns (observed at 2θ of 18.1°, 35.8°, 41.5°, and 60.1°) and the FT–IR spectra (-NH2 group for 1635 and 1517 cm−1, and -OH group for 3482 cm−1) illustrated that CS was successfully loaded on the Mxene. The effects of solution pH, the dosage of Mxene–CS, and duration time on the adsorption of Cr(VI) by synthesized Mxene–CS were investigated. The removal efficiency of Cr(VI) was increased from 12.9% to 40.5% with Mxene–CS dosage ranging from 0.02 to 0.12 g/L. The adsorption process could be well fitted by the pseudo–second–order kinetics model, indicating chemisorption occurred. The Langmuir isotherm model could be better to describe the process with a maximum adsorption capacity of 43.1 mg/g. The prepared novel Mxene–CS composite was considered as an alternative for adsorption of heavy metals from wastewater.

Adsorptive removal of As(III) from aqueous solution by waste litchi pericarps

2016 ◽  
Vol 74 (9) ◽  
pp. 2135-2144 ◽  
Author(s):  
Xiaochen Li ◽  
Jinqiu Qi ◽  
Ruixue Jiang ◽  
Jie Li
Keyword(s):  
Contact Time ◽  
Influential Factors ◽  
Isotherm Models ◽  
Solution Ph ◽  
Rate Limiting Step ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting ◽  
Adsorbent Dose

The present study investigated the removal of arsenite anions (AsO33−, referred to as As(III)) from aqueous solutions by waste litchi pericarps (LPs). Influential factors such as the adsorbent dose, contact time, solution pH, and initial As(III) concentration were investigated. The optimum conditions for As(III) adsorption by the LPs occurred at a contact time of 60 min, adsorbent dose of 10.0 g/L, solution pH of 5.0, and initial As(III) concentration of 1 mg/L. A Box–Behnken design with three variables (adsorbent dose, contact time, and solution pH) at three different levels was studied to identify the correlations between the influential factors and the As(III) adsorption; the results showed a significant interaction between the adsorbent dosage and pH. Additionally, adsorption isotherms, kinetics, and thermodynamics were investigated to explore the As(III) adsorption mechanism. Adsorption by the LPs conformed to the Langmuir, Redlich–Peterson, and Koble–Corrigan isotherm models, suggesting that the process proceeds via monolayer, homogeneous adsorption. In addition, the As(III) adsorption could be characterized by a pseudo-second-order mechanism, revealing that the rate-limiting step might be chemisorption. The thermodynamic studies showed that As(III) adsorption by the LPs was spontaneous and endothermic, and disorder at the solid–liquid interface increased in the adsorption process.

Adsorption of In3+ from Aqueous Solutions by Persimmon Tannins-Immobilized Collagen Fiber

2013 ◽  
Vol 788 ◽  
pp. 114-118 ◽  
Author(s):  
Feng Lei Liu ◽  
Zhong Min Wang ◽  
Huai Gang Zhang ◽  
Gui Yin Li ◽  
Huai Ying Zhou
Keyword(s):  
Adsorption Capacity ◽  
Collagen Fiber ◽  
Low Cost ◽  
Initial Solution ◽  
Liquid Ratio ◽  
Solution Ph ◽  
Freundlich Model ◽  
Treatment Conditions ◽  
Pseudo Second Order ◽  
Solid Liquid

In the present work, a novel adsorbent to effectively adsorbed In3+ from an aqueous solution has been prepared by immobilizing persimmon tannin (PT) on collagen fiber. The adsorption capacities of In3+ on the immobilized PT were evaluated under various treatment conditions including the initial solution pH, solid-liquid ratio and temperature. The results showed that the effect of initial solution pH and solid-liquid ratio on the adsorption capacity were remarkable, while the influence of temperature was insignificant. The adsorption capacity reached 420 mg/g at 303 K and pH 5.0 when the initial concentration of In3+ was 100 mg/L and solid-liquid ratio was 0.2. The adsorption isothermal and kinetic data fitted best to the Freundlich model and the pseudo-second-order model, respectively.All these results indicated that adsorbent adsorbed efficiently and could be used as a low-cost alternative for the adsorption of In3+ in wastewater treatment.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH &lt;4 and pH &gt;10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

Synthesis, Characterization and Adsorption Studies of a Graphene Oxide/Polyacrylic Acid Nanocomposite Hydrogel

2021 ◽  
Vol 19 (9) ◽  
pp. 46-54
Author(s):  
Makarim A. Mahdi ◽  
Aymen A.R. Jawad ◽  
Aseel M. Aljeboree ◽  
Layth S. Jasim ◽  
Ayad F. Alkaim
Keyword(s):  
Industrial Effluents ◽  
Langmuir Model ◽  
Isotherm Models ◽  
Nanocomposite Hydrogel ◽  
Adsorption System ◽  
Order Model ◽  
Solution Ph ◽  
Freundlich Model ◽  
Dye Sorption ◽  
Pseudo Second Order

The AAc/GO nanocomposite hydrogel was successfully employed as a polymeric Nano sorbent of the removal efficiency of M G dye from the model. The complication of the mechanism of the adsorption system was completely exposed by examining how solution pH affects adsorption, Ionic strength isotherm models, kinetic models, and thermodynamics. The adsorption of the MG dye was greatly dependent on the solution pH. The Freundlich model has been demonstrated to be the most accurate in describing the MG dye sorption, whilst the Langmuir model was shown to be the least accurate. Additionally, these integrated mechanisms fit nicely within the framework of a pseudo-second-order model. Additionally, the contact time at equilibrium short (ten minutes) required to MG removes demonstrates the AAc/GO nanocomposite hydrogel can be considered an efficient and potentially useful adsorbent for MG removal from industrial effluents.

ELUTION BEHAVIOR OF PHOSPHATE CONTAINED IN Mg/Fe AND Zn/Fe LAYERED DOUBLE HYDROXIDES

2012 ◽  
Vol 06 ◽  
pp. 156-161 ◽  
Author(s):  
Masashi Kurashina ◽  
Tomohiro Amatsu ◽  
Takaaki Ochi ◽  
Nozomi Ohigashi ◽  
Eiji Kanezaki
Keyword(s):  
Ion Exchange ◽  
Concentrate Solution ◽  
Sulfate Solution ◽  
Carbonate Solution ◽  
Solution Ph ◽  
Ion Exchange Reaction ◽  
Pseudo Second Order ◽  
Elution Behavior ◽  
Double Hydroxide ◽  
Double Hydroxides

Layered double hydroxide (LDH) is a layered hydroxide and exchangeable anion is intercalated in its interlayer. Application of the LDH as a controlled-release material of interlayer anions has become of interest, thus it is important to clarify the elution behavior of interlayer anions. We synthesized hydrogenphosphate-intercalated Mg / Fe and Zn / Fe LDH and elution of phosphate from these LDH were tested in deionized water, sodium chloride solution, sodium sulfate solution, and sodium carbonate solution. For Mg / Fe LDH, the amount of eluted phosphate increased with time and reached to maximum that increased as higher concentrate solution was used. The elution of phosphate from Mg / Fe LDH could be described by the pseudo second-order equation. This elution behavior was explained as ion-exchange reaction of phosphate with sulfate or carbonate in tested solution by means of kinetic simulation using Runge-Kutta method. In the eluted solution, metal ions contained in the LDH were detected and its amount depended on pH of the tested solution, that is, amounts of eluted Mg and Zn ions were small at higher pH (ca. 10) for Mg / Fe and Zn / Fe LDH respectively, but large amount of Zn ion was detected when 2.03 mol·l-1 carbonate solution (pH = 13) was used. Thus elution of phosphate was caused by two main reactions: ion exchange and decomposition of the LDH.

scholarly journals Preparation of bio-absorbents by modifying licorice residue via chemical methods and removal of copper ions from wastewater

2021 ◽  
Author(s):  
Xiaochun Yin ◽  
Nadi Zhang ◽  
Meixia Du ◽  
Hai Zhu ◽  
Ting Ke
Keyword(s):  
Adsorption Capacity ◽  
Copper Ions ◽  
Order Kinetic ◽  
Solution Ph ◽  
Chemical Methods ◽  
Simple Strategy ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Surface Active ◽  
Adsorption Desorption

Abstract In this paper, a series of bio-adsorbents (LR-NaOH, LR-Na2CO3 and LR-CA) were successfully prepared by modifying Licorice Residue with NaOH, Na2CO3 and citric acid, which were used as the adsorbents to remove Cu2+ from wastewater. The morphology and structure of bio-adsorbents were characterized by Fourier Transform Infrared, SEM, TG and XRD. Using static adsorption experiments, the effects of the adsorbent dosage, the solution pH, the adsorption time, and the initial Cu2+ concentration on the adsorption performance of the adsorbents were investigated. The results showed that the adsorption process of Cu2+ by the bio-adsorbents can be described by pseudo-second order kinetic model and the Langmuir model. The surface structure of the LR-NaOH, LR-Na2CO3 and LR-CA changed obviously, and the surface-active groups increased. The adsorption capacity of raw LR was 21.56 mg/g, LR-NaOH, LR- Na2CO3 significantly enhanced this value up to 43.65 mg/g, 43.55 mg/g, respectively. After four adsorption-desorption processes, the adsorption capacity of LR-NaOH also maintained about 73%. Therefore, LR-NaOH would be a promising adsorbent for removing Cu2+ from wastewater, and the simple strategy towards preparation of adsorbent from the waste residue can be as a potential approach using in the water treatment.

Pathway and Kinetic of Dechlorination of Trichloroethylene in Water by Supported Nanoscale Bimetallic Fe-Cu Particles

2011 ◽  
Vol 213 ◽  
pp. 126-130
Author(s):  
Huan Zhang ◽  
Ying Xue Zheng ◽  
Hai Tao Wang
Keyword(s):  
Ph Value ◽  
Reaction System ◽  
Surface Concentration ◽  
Batch Experiments ◽  
Solution Ph ◽  
Cu Content ◽  
Kinetics Studies ◽  
Reaction Solution ◽  
Pseudo Second Order ◽  
Dechlorination Reaction

In this paper, exfoliated graphite supported nanoscale Fe-Cu is synthesized by aqueous-phase reductive method. The effect trichloroethene (TCE) reduction by the supported nanoscale Fe-Cu bimetal is researched in the batch experiments. Kinetics studies show that the reduction of TCE process obeys pseudo-second-order kinetics. The kinetic constants of TCE reduction by supported nano bimetal are measured at different nano Fe0 dosage and Cu content on bimetal in this study. When the dosage of supported nano Fe0 in bimetal with 4wt% Cu is 1.25g/L in reaction solution, the kSA of dechlorination reaction for TCE is higher than other nano Fe0 dosage. The dechlorination speed becomes lower as well as kSA and kobs decreasing with increasing the Fe0 dosage. Supported Fe-Cu bimetal with 4wt% Cu content exhibits the best dehalogenation effect than those with other contents of Cu. The generation of H2 and effect of Cu analysis influence the TCE dechloriation and hydrogenation in the surface of bimetal to a different extent. Excess nano Fe0 existing in the reaction system can generate plenty of H2 as well as increasing the solution pH value so that decrease the surface concentration of bimetal reactive sites and then hinder the TCE dechlorination in surface of bimetal. Cu as catalysis metal could accelerate the process of TCE dechlorination and hydrogenation.

The Use of Recycled Aggregate Sludge for the Preparation of GGBFS and Fly Ash Based Geopolymer

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1486
Author(s):  
Yi-Chen Chen ◽  
Wei-Hao Lee ◽  
Yung-Chin Ding
Keyword(s):  
Fly Ash ◽  
Environmental Concern ◽  
Waste Product ◽  
Recycled Aggregate ◽  
Test Results ◽  
Granulated Blast Furnace Slag ◽  
Mechanical And Physical Properties ◽  
Preliminary Study ◽  
Solid Liquid ◽  
High Treatment

Aggregate sludge is a waste product produced from crushing, screening, and washing processes at aggregate plants. Because of the large quantity and high treatment cost of this sludge, it cannot be disposed of as landfill, and thus, has caused environmental concern over the years in Taiwan. In this preliminary study, the recycled aggregate sludge was reutilized for construction applications through the geopolymerization process. The ground granulated blast furnace slag (GGBFS) and fly ash (FA) were selected as alkaline activated materials for the fabrication of sludge geopolymer. Several process parameters that may affect the mechanical and physical properties of geopolymer were investigated. These parameters are sludge/GGBFS/FA ratios, solid/liquid (alkali solution) ratio, the molarity of NaOH, and curing time. According to the test results, the compressive strength of geopolymer specimens (70/30 sludge/GGBFS ratios) made with 4 M and 6 M NaOH can reach 39.17 MPa and 43.6 MPa after 28 days of curing. The specimen made with 60/40 sludge/GGBFS ratios has a strength of 61.3 MPa. After replacing GGBFS with 10% fly ash (70/20/10 sludge/GGBFS/FA), the strength of the specimen can also reach 43 MPa. According to the test results obtained in this study, it was found that the higher the NaOH concentration, the higher the strength of the geopolymer, and the GGBFS also can contribute more to the mechanical properties of geopolymer than fly ash. This preliminary study suggests that it is possible to reutilize aggregate sludge for construction applications and solve its environmental disposal problem.

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