scholarly journals Enhanced removal of Cr(VI) using a modified environment-friendly adsorbent

2021 ◽  
Author(s):  
Shan Liu ◽  
Lei Cao ◽  
Xincheng Tian ◽  
Xuanni Li ◽  
Lei Liao ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Ph Value ◽  
Morphological Characteristics ◽  
Single Layer ◽  
Solution Ph ◽  
Layer Adsorption ◽  
Chloride Hexahydrate ◽  
Ferric Chloride Hexahydrate ◽  
Initial Adsorption ◽  
Physical And Chemical

Abstract Chitosan (CS) was modified by Ferric Chloride Hexahydrate (FeCl3·6H2O) and Sodium laurylsulfonate (SLS) to prepare compound adsorbent CS-Fe-SLS. Taking Cr(VI) as the target pollutant, the influence of different factors (solution pH, adsorption time, initial adsorption concentration and coexisting ions) were investigated. The results showed that the optimal pH value for Cr(VI) adsorption by CS-Fe-SLS was 3.0; The adsorption equilibrium of Cr(VI) on CS-Fe-SLS reached at 120 min, both of physical and chemical process impacted on the adsorption process; The maximum adsorption value was 131.91 mg/g, the adsorption was both single-layer adsorption and multilayer adsorption; Common co-ions such as Cl−, NO3− and SO42− had little effect on the adsorption, whereas CO32− greatly involved in the adsorption process. When Cu(II) and Cr(VI) coexisted in the solution, the adsorption strength of the adsorbent on Cr(VI) increased. The characterization results of SEM, FTIR and XRD showed that: CS-Fe-SLS and CS had different morphological characteristics. In constrast with CS, CS-Fe-SLS possessed larger volume and more flakes on the surface. SLS and Fe(III) were successfully loaded on CS. The adsorption Cr(VI) was related to -NH and -OH on the material. Some Cr(VI) were reduced to Cr(III) during the adsorption process. CS-Fe-SLS was significantly lower in crystallinity than that of CS, and was more irregular and amorphous in shape, the experimental results showed that CS-Fe-SLS had better adsorption capacity for Cr(VI).

scholarly journals Adsorption Characteristics and Mechanism of Bisphenol A by Magnetic Biochar

2020 ◽  
Vol 17 (3) ◽  
pp. 1075 ◽  
Author(s):  
Jinpeng Wang ◽  
Ming Zhang
Keyword(s):  
Bisphenol A ◽  
Exothermic Reaction ◽  
Chemical Properties ◽  
Solution Ph ◽  
Acceptor Interaction ◽  
Endocrine Disrupting Chemical ◽  
Magnetic Biochar ◽  
Grapefruit Peel ◽  
Initial Adsorption ◽  
Physical And Chemical

In this paper, biochar (BC) was prepared from discarded grapefruit peel and modified to prepare magnetic biochar (MBC). Physical and chemical properties of BC and MBC were characterized, and the results showed that the type of iron oxide loaded by MBC was γ-Fe2O3. Compared with BC, MBC has a larger specific surface area and pore volume, with more oxygen-containing functional groups on the surface. BC and MBC were used to adsorb and remove endocrine-disrupting chemical (EDC) bisphenol A (BPA) from simulated wastewater. The results showed that the adsorption kinetics and adsorption isotherm of BPA adsorption by BC and MBC were mainly in accordance with the pseudo-second-order kinetics model and the Langmuir model. This indicates that the adsorption of BPA on BC and MBC is mainly a chemically controlled monolayer adsorption. Adsorption thermodynamics show that BC and MBC adsorption of BPA is a spontaneous exothermic reaction, and lowering the temperature is conducive to the adsorption reaction. The effect of solution pH on the adsorption of BPA by both was significant. The optimum pH for BC and MBC to absorb BPA was 6 and 3, respectively. The concentration of Na+ in the range of 0–0.10 mol·L−1 can promote the adsorption of BPA to MBC. MBC loaded with γ-Fe2O3 not only has excellent magnetic separation ability, but can also reach about 80% of the initial adsorption capacity after four cycles of adsorption. By analyzing the adsorption mechanism, it was found that the H-bond and the π–π electron donor–acceptor interaction (EDA) were the main forces for BC and MBC to adsorb BPA.

scholarly journals Kinetics, Isotherm and Thermodynamic Studies for Efficient Adsorption of Congo Red Dye from Aqueous Solution onto Novel Cyanoguanidine-Modified Chitosan Adsorbent

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4446
Author(s):  
Nouf F. Al-Harby ◽  
Ebtehal F. Albahly ◽  
Nadia A. Mohamed
Keyword(s):  
Aqueous Solution ◽  
Congo Red ◽  
Adsorption Process ◽  
Ph Value ◽  
Dye Adsorption ◽  
Order Kinetic ◽  
Amino Groups ◽  
Solution Ph ◽  
Intraparticle Diffusion Model ◽  
Modified Chitosan

Novel Cyanoguanidine-modified chitosan (CCs) adsorbent was successfully prepared via a four-step procedure; first by protection of the amino groups of chitosan, second by insertion of epoxide rings, third by opening the latter with cyanoguanidine, and fourth by restoring the amino groups through elimination of the protection. Its structure and morphology were checked using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The adsorption capacity of CCs for Congo Red (CR) dye was studied under various conditions. It decreased significantly with the increase in the solution pH value and dye concentration, while it increased with increasing temperature. The adsorption fitted to the pseudo-second order kinetic model and Elovich model. The intraparticle diffusion model showed that the adsorption involved a multi-step process. The isotherm of CR dye adsorption by CCs conforms to the Langmuir isotherm model, indicating the monolayer nature of adsorption. The maximum monolayer coverage capacity, qmax, was 666.67 mg g−1. Studying the thermodynamic showed that the adsorption was endothermic as illustrated from the positive value of enthalpy (34.49 kJ mol−1). According to the values of ΔG°, the adsorption process was spontaneous at all selected temperatures. The value of ΔS° showed an increase in randomness for the adsorption process. The value of activation energy was 2.47 kJ mol−1. The desorption percentage reached to 58% after 5 cycles. This proved that CCs is an efficient and a promising adsorbent for the removal of CR dye from its aqueous solution.

scholarly journals Different Insights into Silicate Rectorite Modification and Its Role in Removal of Heavy Metal Ions from Wastewater

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 176 ◽  
Author(s):  
Ya Gao ◽  
Hao Jiang ◽  
Xianyuan Li ◽  
Sultan Ahmed Khoso ◽  
Guoyuan Xiang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Adsorption Process ◽  
Underlying Mechanism ◽  
Xps Analysis ◽  
Adsorption Efficiency ◽  
Removal Capacity ◽  
Chloride Hexahydrate ◽  
Ferric Chloride Hexahydrate

In the field of water management, the separation of metal contaminants from wastewater is very important and challenging. This study systematically investigated the effect and underlying mechanism of silicate rectorite (REC) on the removal of heavy metal ions (Cr(VI) and Pb(II)) from wastewater. The adsorption and removal capacity of REC was further improved by its novel modification with ferric chloride hexahydrate. Compared to natural REC, the modified rectorite (Fe-REC) showed comparatively superior adsorption efficiency for both Cr(VI) and Pb(II) due to the chemisorption of Fe3+ on the REC surface as its oxidation state (Fe–O, Fe–OH, Fe–OOH). Adsorption on Cr(VI) attributed to the reaction between iron hydroxy complexes (FeOH2+, Fe(OH)2+ and Fe(OH)3(aq)) and Cr(VI) species (HCrO4− and CrO42−) in the aqueous solution. This reaction was perfectly consistent with the binding energy shifts in O 1s and Fe 2p species, as reflected by XPS analysis. While, the existence of –Al–OH and –Si–OH in silicate REC slurry reacted with PbOH+ colloids produced from lead ions hydrolysis to promote Pb(II) adsorption. Zeta potential after modification and removal occurred to shift positively or negatively to testify the adsorption of Fe3+ and heavy metal ions. Freundlich and Langmuir isotherms conformed adsorption process for Cr(VI) and Pb(II), respectively.

Effect of Cu2+ on the Activation to Muscovite Using Electrochemical Pretreatment

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 206 ◽  
Author(s):  
Yubin Wang ◽  
Yan Wang ◽  
Wei Xiao ◽  
Yaru Wei ◽  
Shuqin Li
Keyword(s):  
Sodium Oleate ◽  
Ph Value ◽  
Copper Ions ◽  
Electronic Energy ◽  
Solution Ph ◽  
Electrostatic Adsorption ◽  
Electrochemical Pretreatment ◽  
Solution Conductivity ◽  
Physical And Chemical ◽  
Hydrolysis Of

In this study, electrochemistry pretreatment flotation of muscovite was carried out and the flotation behavior and mechanism of muscovite in the system of sodium oleate and Cu2+ion was characterized by solution pH value detection, solution conductivity detection, zeta potential, infrared spectrum and the electronic energy spectrum. The results indicated that under the conditions of muscovite mass of 10.00 g, pulp mass concentration of 13.33%, flotation speed of 1750 r/min, sodium oleate concentration of 9.20 × 10−4 mol/L and Cu2+ concentration of 6 × 10−5 mol/L, electrochemical pretreatment of Cu2+ could strengthen the activation of muscovite. Electrochemical pretreatment of Cu2+ solution can inhibit the hydrolysis of copper ions, increase the content of Cu2+ in the solution, strengthen the adsorption of Cu2+ on the muscovite surface, and enhance the electrostatic adsorption of sodium oleate on the muscovite surface, thereby strengthening the physical and chemical adsorption of sodium oleate on the muscovite surface.

Adsorption Isotherms and Kinetic Models for Congo Red Adsorption on Ca-Al Layer Double Hydroxide Adsorbent

2019 ◽  
Vol 298 ◽  
pp. 128-132 ◽  
Author(s):  
To Uyen T. Dao ◽  
Hong Tham T. Nguyen ◽  
Do Trung Sy ◽  
Khoa Hien Nguyen ◽  
Anh Tien Nguyen ◽  
...  
Keyword(s):  
Kinetic Data ◽  
Adsorption Process ◽  
Single Layer ◽  
Chemical Processes ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Layer Double Hydroxide ◽  
Layer Adsorption ◽  
Pseudo Second Order ◽  
Double Hydroxide

The equilibrium and physicochemical properties of the Ca-Al LDH material were determined in this study. Kinetic data were analyzed using isothermal models including Langmuir, Freundlich, Temkin and Dubinin–Radushkevich. Adsorption behavior is well described by the Langmuir isotherm and the pseudo-second-order model. The maximum adsorption capacity of CR on Ca-Al LDH is found to be 72.569 mg/g. The uptake results indicated that the adsorption process was controlled by chemical processes and single-layer adsorption. Due to, the Ca-Al LDH material may be become an effective adsorbent for removal CR dye in aqueous solution.

scholarly journals Study on the removal of high contents of ammonium from piggery wastewater by clinoptilolite and the corresponding mechanisms

2019 ◽  
Vol 17 (1) ◽  
pp. 1393-1402
Author(s):  
Liu Nan ◽  
Li Yingying ◽  
Li Jixiang ◽  
Ouyang Dujuan ◽  
Wang Wenjuan
Keyword(s):  
Contact Time ◽  
Adsorption Process ◽  
Ph Value ◽  
Optimal Conditions ◽  
Solution Ph ◽  
Piggery Wastewater ◽  
Column Study ◽  
Ammonium Removal ◽  
Ammonium Adsorption ◽  
Pseudo Second Order

AbstractIn this study, a clinoptilolite was applied to remove ammonium from piggery wastewater. The performance of ammonium removal and the correspondingly mechanisms were discussed. Under the optimal conditions of clinoptilolite dosage of 12 g/L, solution pH value of 8.3, shaking speed of 280 rpm and contact time of 55 min obtained by using response surface methodology (RSM), 19.7 mg of ammonium can be adsorbed onto 1 g of clinoptilolite, which was declined when metal cations were presented in the piggery wastewater. The ammonium adsorption process by the clinoptilolite can be well fitted by Langmuir isotherm with a spontaneous nature and pseudo–second–order kinetics model. Furthermore, column study showed that to some extent, the increased flow rate was beneficial to the removal of ammonium, and the ammonium adsorption capacity of clinoptilolite in column study was much higher than those in batch study.

Stabilization of As in Soil Using Two Kinds of Fe(III) Salts

2015 ◽  
Vol 768 ◽  
pp. 142-149 ◽  
Author(s):  
Lin Liu ◽  
Zhi Hui Yang ◽  
Li Yuan Chai ◽  
Ying Ping Liao ◽  
Wen Bin Yao ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Treatment Time ◽  
Ph Value ◽  
Water Soluble ◽  
Technological Parameters ◽  
Stabilizing Agents ◽  
Arsenic Mobility ◽  
Chloride Hexahydrate ◽  
Ferric Chloride Hexahydrate ◽  
The Relationship

The purpose of this study reports chemical immobilization of As in contaminated soil, using ferric sulfate (Fe2(SO4)3) and ferric chloride hexahydrate (FeCl3·6H2O) as stabilizing agents. The optimum treatment solutions were identified based on the immobilizing efficiency of water-soluble and NaHCO3-extractable arsenic. The results showed significant decreases of water and NaHCO3-extractable arsenic in soil. Optimization of technological parameters: dosage, treatment time and soil moisture, on arsenic remediation were studied. The immobilization efficiency of NaHCO3-extractable As attained 83.64% with using 5.5% Fe2(SO4)3, meanwhile that of As could reach 74.50% with adding the same ratio of FeCl3·6H2O. The relationship between As immobilization effects and reaction time indicated that arsenic mobility obtained stability after 7 days treatment. Simultaneously, moisture had slightly influence on chemical stabilization, while the immobilization efficiency of ferric chloride hexahydrate was relatively higher under less moisture content. However, soil pH value decreased with the amount of stabilizing agents increasing, which limited the mass ratio of fixative/soil cannot to be much high during treating process.

scholarly journals Kinetic, Isotherm, and Thermodynamic Studies for Ag(I) Adsorption Using Carboxymethyl Functionalized Poly(glycidyl methacrylate)

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1090 ◽  
Author(s):  
Jiling Zhao ◽  
Shixing Wang ◽  
Libo Zhang ◽  
Chen Wang ◽  
Bing Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Glycidyl Methacrylate ◽  
Adsorption Process ◽  
Removal Rate ◽  
Single Layer ◽  
Silver Ions ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Kinetics And Isotherms

Industrial wastewater contains large amounts of silver ions. Here, a new adsorbent was synthesized by functionalizing poly(glycidyl methacrylate) with carboxymethyl groups. The adsorbent was used to recover Ag(I) in wastewater. Fourier transform infrared spectroscopy, zeta potential, scanning electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the adsorbent. The experimental parameters affecting the adsorption are solution pH, contact time, and initial silver ion concentration. The optimum pH for adsorption of Ag(I) is pH 4. The maximum adsorption capacity at pH 4 is 157.05 mg/g, and the adsorption reaches equilibrium at 300 min. The kinetics and isotherms of the adsorption process were described by pseudo second-order, Langmuir and D-R models, respectively. The adsorption process was a single layer chemical adsorption, exothermic, feasible, and spontaneous. The adsorption mechanism is electrostatic or chelation. The adsorbent selectively absorbed Ag(I) from coexisting ions (Cu2+, Ni2+, Co2+, Zn2+). Finally, the removal rate of silver ions decreased from 79.29% to 65.01% after four repetitive experiments, which proved that the adsorbent had good reusability. The adsorbent has great potential benefit in removing Ag(I).

Adsorption for Au3+ by Persimmon Tannins Immobilized on Collagen Fiber

2013 ◽  
Vol 745-746 ◽  
pp. 39-45 ◽  
Author(s):  
Feng Lei Liu ◽  
Zhong Min Wang ◽  
Jian Cui ◽  
Zhi De Zhou ◽  
Gui Yin Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Collagen Fiber ◽  
Adsorption Process ◽  
Ph Value ◽  
Hydroxyl Groups ◽  
Adsorption Behaviour ◽  
Solution Ph ◽  
Initial Concentration ◽  
Ft Ir ◽  
Precious Metal Ions

A novel adsorbent which is effective to adsorb Au3+ was prepared using immobilized persimmon tannin (PT) on collagen fiber by glutaraldehyde crosslinking. The adsorption behaviour of this new adsorbent to Au3+ in aqueous solution was investigated. The effects of various factors such as initial solution pH, temperature, ionic strength and initial concentration of Au3+ on the influence of the adsorption process were studied. The equilibrium adsorption capacity reached 2347 mg/g at 323 K and pH value 2.0 when the initial concentration of Au3+ in aqueous solution was 500 mg/L. The immobilized PT was characterized by FT-IR, XRD and SEM. The results indicated that Au3+ changed to gold by oxidation adjacent phenol hydroxyl groups of persimmon tannin. Experiments also showed that adsorption isotherms of immobilized tannin for Au3+ could be described by Langmuir models. Immobilized PT adsorption provided a new way for the separation of the precious metal ions

Adsorption of Mn2+ Ion in Groundwater with Modified Bentonite

2012 ◽  
Vol 550-553 ◽  
pp. 2174-2177
Author(s):  
Chun Hua Liu ◽  
Chang Bin Xia
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
Ph Value ◽  
Surface Complex ◽  
Solution Ph ◽  
Modified Bentonite ◽  
Higher Temperature ◽  
Adsorption Capability ◽  
Main Factor

The adsorption of Mn2+ion on natural bentonite heated-treated at 110 °C or 200 °C and on acid-treated with H2SO4from aqueous solutions has been investigated under different conditions,such as intial solution pH and initial Mn2+ion concentration.The results show that modified bentonite has a better adsorption capability,and the pH value is the main factor affecting adsorption;bentonite modified at higher temperature has the largest adsorption capability.The adsorption process in solution exhibits Langmuir behaviour and ion exchange and surface complex are chief adsorption form.

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