scholarly journals Adsorptive Removal of Arsenic by Synthetic Iron-loaded Goethite: Isotherms, Kinetics, and Mechanism

2021 ◽  
Author(s):  
Shakeel Ahmed Talpur ◽  
Muhammad Yousuf Jat Baloch ◽  
Chunli Su ◽  
Javed Iqbal ◽  
Aziz Ahmed
Keyword(s):  
Binding Sites ◽  
Arsenic Removal ◽  
Binding Energies ◽  
Coefficient Of Determination ◽  
Maximum Adsorption Capacity ◽  
Surface Binding ◽  
Arsenic Adsorption ◽  
Freundlich Isotherms ◽  
Best Fitting ◽  
Removal Of Arsenic

Abstract Arsenic contamination in the groundwater is a worldwide concern. Therefore, this study was designed to use synthetic iron-loaded goethite to remove arsenic. Adsorption was significantly pH-dependent; hence, pH values between 5.0 and 7.0 resulted in the highest removal of arsenate and arsenite. Langmuir and Freundlich isotherms were almost perfectly matched in terms of strong positive coefficient of determination “R2” arsenate – 0.941 and 0.992 and arsenite – 0.945 and 0.993. The adsorption intensity “n” resulted as arsenate – 2.542 and arsenite – 2.707; besides separation factor “RL” found as arsenate – 0.1 and arsenite – 0.5, respectively. However, both “n” and “RL” leads to a favourable adsorption process. Temkin isotherm yielded in equal binding energies “bt” showing as 0.004 (J/μg) for both arsenate and arsenite. Jovanovic monolayers isotherm was dominated by the Langmuir isotherm. This resulting in maximum adsorption capacity “Qmax” of arsenate – 1369.877 and arsenite – 1276.742 (μg/g), which approaches to the saturated binding sites. Kinetic data revealed that adsorption equilibrium was achieved in 240 – arsenate and 360 – arsenite (minutes), respectively. Chemisorption was found effective with high “R2” values 0.981 ­– arsenate and 0.994 – arsenite, respectively, with the best fitting of pseudo-second order. Moreover, Brunauer Emmett Teller (BET), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were used to determine the morphological content, surface area, crystalline structure, and chemical characteristics of the adsorbent. It is anticipated that optimal arsenic removal was achieved by the porosity, chemical bindings, and surface binding sites of the adsorbent.

Removal of Arsenic from Groundwater Using Nano-Metal Oxide Adsorbents

2017 ◽  
Vol 751 ◽  
pp. 766-772 ◽  
Author(s):  
Phitchaya Muensri ◽  
Supamas Danwittayakul
Keyword(s):  
Particle Size ◽  
Arsenic Removal ◽  
Average Particle Size ◽  
Sample Volume ◽  
Adsorptive Capacity ◽  
Hydroxyl Groups ◽  
Average Particle ◽  
Human Beings ◽  
Arsenic Adsorption ◽  
Removal Of Arsenic

Arsenic can be found in groundwater that is harmful to human beings. In this research, we present the potential uses of ZnO microparticles, ZnO and TiO2 nanoparticles to removal arsenic in groundwater. The experiments of %arsenic removal upon using ZnO microparticles ZnO and TiO2 nanoparticles were conducted in 25 mL of sample volume with 0.05 g of nanoadorpbents at pH 6. We found that the efficiency of arsenic adsorption increased with a reduction of particle size of theadsorbents. Upon using nanoadsorbents to remove arsenic from the solutions with the concentrations of 200-2000 ppb, we found that the %removal of arsenic decreased from 100% to 84% for ZnO nanoparticles and 100% to 97% for TiO2 nanoparticles. Adsorption capacities upon using ZnO and TiO2 nanoparticles were 0.85 and 0.99 mg of arsenic/g of sorbents, respectively. TiO2 nanoparticles exhibited a better adsorption ability to arsenic than that ZnO because TiO2 nanoparticles had a smaller average particle size and larger surface area allowed the adsorption of hydroxyl groups on the surface that could bond with in coming HAsO42- via hydrogen bonding resulting in a better arsenic adsorptive capacity.

scholarly journals Adsorption of arsenic and phosphate from groundwater onto a calcined laterite as fixed bed in column experiments

2020 ◽  
Vol 8 (2) ◽  
pp. 227-243
Author(s):  
Yacouba Sanou ◽  
Raymond Kabore ◽  
Samuel Pare
Keyword(s):  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Fixed Bed ◽  
Column Experiments ◽  
Arsenic Adsorption ◽  
Experimental Conditions ◽  
Ph Values ◽  
Naoh Solution ◽  
Removal Of Arsenic ◽  
Maximum Removal

This work was focused on laterite soil as adsorbent for the removal of arsenic and phosphate from groundwater using column experiments. Results revealed a decrease of arsenic removal efficiency from 100 to 79% with flow rate increasing. Maximum removal of 100% for arsenic and 85% for phosphates was obtained for pH values between 3.5 and 6. The increase of initial arsenic concentration and phosphate amount caused an increase of arsenic adsorption up to 24 µg/g while 58.5 µg/g for phosphate. NaOH solution could desorb 86.8% of arsenic and the reuse of regenerated laterite indicated its efficiency in same experimental conditions.

Study on Mn-Fe-LDH Material for Remediation of Arsenic Contaminated Water

2017 ◽  
Vol 730 ◽  
pp. 200-205 ◽  
Author(s):  
Wei Zhuo Wang ◽  
Jian Min Bian
Keyword(s):  
Layered Double Hydroxides ◽  
Arsenic Removal ◽  
Adsorption Property ◽  
Toxic Substances ◽  
Arsenic Adsorption ◽  
Exchange Method ◽  
Main Method ◽  
Series Of Experiments ◽  
Removal Of Arsenic ◽  
Double Hydroxides

Arsenical water pollution refers to the toxicity of arsenic. The form of trivalent arsenic has been seen as more toxic substances, which will be great improved by the manmade pollution. Compared with other technologies, adsorption is the main method of removal of arsenic pollution, for its higher efficiency and lower cost. Based on the adsorption theory and ion exchange method, the layered double hydroxides material containing ferric iron and manganese (Mn-Fe-LDH) was prepared to remove arsenic in this paper. We have designed some experiments for synthesis of this material. The reaction process and elemental compositions has been studied and the adsorption property of arsenic adsorption onto layered double hydroxides was verified through a series of experiments. Study shows that the Mn-Fe-LDH material can be used as a good adsorbent material for its high removal efficiency. The adsorption capacity of the Mn-Fe-LDH material is not affected by the interference of pH and Cl-/SO42- ion strength. It was a broad prospect for the development and application of arsenic removal materials.

scholarly journals Enhanced As(III) sequestration using nanoscale zero-valent iron modified by combination of loading and sulfidation: characterizations, performance, kinetics and mechanism

2021 ◽  
Author(s):  
Shun Cheng ◽  
Hong Liu ◽  
Emmanuella Anang ◽  
Chunxia Li ◽  
Xianyuan Fan
Keyword(s):  
Arsenic Removal ◽  
Average Particle Size ◽  
Zero Valent Iron ◽  
Maximum Adsorption Capacity ◽  
Average Particle ◽  
Order Kinetic ◽  
Arsenic Adsorption ◽  
Nanoscale Zero Valent Iron ◽  
Wide Ph Range ◽  
Co Precipitation

Abstract Nanoscale zero-valent iron (nZVI) and sulfides have been confirmed to be effective in arsenic sequestration from aqueous solution. In this study, attapulgite supported and sulfide-modified nanoscale zero-valent iron (S-nZVI@ATP) are synthesized to realize the superposition effect of enhanced arsenic sequestration. The results indicated that nZVI clusters were well disaggregated and the BET specific surface area increased from 19.61 m2·g−1 to 46.04 m2·g−1 of S-nZVI@ATP, resulting in an enhanced removal efficiency of arsenic from 51.4% to 65.1% at 20 min. The sulfides in S-nZVI@ATP mainly exists as mackinawite (FeS) and causes the spherical nanoparticles exhibiting a larger average particle size (94.6 nm) compared to bare nZVI (66.0 nm). In addition, S-nZVI@ATP exhibited a prominent ability for arsenic sequestration over a wide pH range of 3.0–6.0. The presence of anions SO42− and Cl− can enhance the arsenic removal whereas HCO3− inhibited it. The arsenic adsorption by S-nZVI@ATP could be explained by the pseudo-second-order kinetic model and the Langmuir model, with the maximum adsorption capacity of 193.8 mg·g−1. The mechanism of As(III) sequestration by S-nZVI@ATP involved multiple processes, mainly including precipitation conversion from FeS to As2S3, surface-complexation adsorption and co-precipitation.

scholarly journals Development of ion-imprinted cryogels for selective removal of arsenic from environmental waters

2019 ◽  
Vol 9 (4) ◽  
pp. 4119-4125
Keyword(s):  
Adsorption Capacity ◽  
Arsenic Removal ◽  
Removal Rate ◽  
Anthropogenic Activities ◽  
Arsenic Concentration ◽  
Environmental Water ◽  
Maximum Adsorption Capacity ◽  
Environmental Waters ◽  
Ion Imprinted ◽  
Removal Of Arsenic

Arsenic present by nature as metalloid, having transportability in the environment via diverse sources. Because of both natural processes and anthropogenic activities, arsenic is found in environmental water sources. The aim of this study is to design ion-imprinting-based cryogel adsorbents for the removal of arsenic species from environmental waters. Since trivalent arsenic exhibit a high afgfinity for sulfhydryl groups, cysteine-based functional monomer, i.e. MAC, was synthesized and MAC–As(III) complex was prepared. Ionimprinted polymeric adsorbents were fabricated via cryopolymerization. Elemental analysis studies have shown that the cryogel monolith contains 192.8 μmol/g mol MAC/g polymer. The maximum adsorption capacity of ion-imprinted cryogels at an initial arsenic concentration of 10 ppm was found to be 372.5 μg/g at pH 8.0. Arsenic removal rate of the imprinted cryogels from environmental water sample was determined as 94.8% In the studies carried out for the removal of arsenic from the environmental waters, 94.8% removal efficiency was achieved. Reusability assays of ion-imprinted cryogels were performed and there was no significant decrease in adsorption capacity.

scholarly journals Activated Carbons for Arsenic Removal from Natural Waters and Wastewaters: A Review

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 2982
Author(s):  
Elie Meez ◽  
Athanasia K. Tolkou ◽  
Dimitrios A. Giannakoudakis ◽  
Ioannis A. Katsoyiannis ◽  
George Z. Kyzas
Keyword(s):  
Natural Waters ◽  
Arsenic Removal ◽  
Activated Carbons ◽  
Ph Value ◽  
Critical Role ◽  
Freundlich Isotherms ◽  
Removal Capacity ◽  
Characterization Of Materials ◽  
Removal Of Arsenic

The arsenic pollution of waters and wastewaters is concerning many countries across the world, and because of the effects of arsenic on human health, its removal from waters is of great importance. Adsorption using functionalized activated carbons as a technique for the removal of arsenic from water streams has gained great attention. In the present review, we summarize synthesis technologies, the characterization of materials and arsenic removal capacity, and we clarify the parameters which play a critical role in the removal of arsenic, such as the pH value of the water, the active group in the functionalization and temperature. The review article concludes that most of the experimental data fit both Langmuir and Freundlich isotherms. In this review, the recyclability and reuse of the materials are also reported, and the findings show that for both arsenite and arsenate, even after several adsorption cycles, the material can be further used as an efficient adsorbent for arsenic removal.

scholarly journals Preparation of Activated Carbon from Lapsi Seed Stone and its Application for the Removal of Arsenic from Water

1970 ◽  
Vol 8 (1-2) ◽  
pp. 211-218 ◽  
Author(s):  
Rinita Rajbhandari ◽  
Lok Kumar Shrestha ◽  
Raja Ram Pradhananga
Keyword(s):  
Activated Carbon ◽  
Iodine Number ◽  
Zinc Chloride ◽  
Arsenic Removal ◽  
Chemical Activation ◽  
Nitrogen Atmosphere ◽  
Arsenic Adsorption ◽  
Point Of Use ◽  
Removal Of Arsenic ◽  
Iron Impregnation

In this paper, Guaranteed Services Token (GuST) protocol for integrated Adsorption of arsenic by activated carbon prepared from locally available Lapsi seed stone is presented. Activated carbon has been prepared by carbonization of Lapsi seed stone (chorespondias axillaris, Roxb) in a nitrogen atmosphere at 400°C. Chemical activation using a 1:1 ratio of Lapsi seed stone powder and zinc chloride followed by iron impregnation greatly enhanced the arsenic adsorption capacity for adsorption of arsenic from ground water. Activated carbon of dose 2g/L decreased the concentration of arsenic in water from 800 ppb to below the interim guide line value of 50 ppb of arsenic in drinking water of Nepal. The iodine number of raw carbon is quite low but chemical activation using 1:1 Lapsi seed powder and zinc chloride at 400°C increased the iodine number to 791mg/g. Iron impregnated activated carbon prepared from locally available Lapsi seed stones can be used in community level at point- of- use for treatment of arsenic contaminated ground water.Key words: activated carbon; Arsenic removal; Adsorption; Chorespondias axillaris; Iron impregnated carbonDOI: http://dx.doi.org/10.3126/jie.v8i1-2.5113Journal of the Institute of Engineering Vol. 8, No. 1&2, 2010/2011Page: 211-218Uploaded Date: 20 July, 2011

Phosphonium grafted styrene–divinylbenzene resins impregnated with iron(III) and crown ethers for arsenic removal

2014 ◽  
Vol 86 (11) ◽  
pp. 1729-1740 ◽  
Author(s):  
Adina Negrea ◽  
Adriana Popa ◽  
Mihaela Ciopec ◽  
Lavinia Lupa ◽  
Petru Negrea ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Underground Water ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Iron Ions ◽  
Arsenic Adsorption ◽  
Equilibrium Data ◽  
Styrene Divinylbenzene

Abstract In the present work a polymer with phosphonium pendant groups impregnated with crown ether (dibenzo-18-crown-6) and loaded with iron ions was investigated for arsenic removal through adsorption from aqueous solutions. The impregnated polymer was loaded with iron ions due to the high affinity of arsenic to it. The characterization of the surface modification of the obtained new adsorbent material was performed on the basis of energy dispersive X-ray analysis; scanning electron microscopy and Fourier transform infrared spectroscopy. The arsenic adsorption was investigated, including effect of pH, arsenic initial concentration, the shaking time and temperature. The effect of the pH was examined over the range 2–11. The adsorption of As(V) increases with pH increasing reaching a maximum at pH higher than 8. Equilibrium, kinetic and thermodynamic studies were carried out to study the adsorption performance of the obtained material in the removal process of arsenic from aqueous solutions. For the studied materials the equilibrium data closely fitted Langmuir model and was achieved a maximum adsorption capacity of 32.6 μg As(V)/g of material. The pseudo-second order kinetic model is suitable for describing the adsorption system. The obtained results show that the studied adsorbent can be used with efficiency in the arsenic removal from underground water even from low influent arsenic concentration solutions.

scholarly journals Energy Efficient Rapid Removal of Arsenic in an Electrocoagulation Reactor with Hybrid Fe/Al Electrodes: Process Optimization Using CCD and Kinetic Modeling

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2876 ◽  
Author(s):  
Saif Ullah Khan ◽  
Izharul Haq Farooqi ◽  
Muhammad Usman ◽  
Farrukh Basheer
Keyword(s):  
Energy Consumption ◽  
Arsenic Removal ◽  
Low Cost ◽  
Minimum Energy ◽  
Ferric Hydroxide ◽  
Cost Effective ◽  
Complete Removal ◽  
Coefficient Of Determination ◽  
Time Duration ◽  
Removal Of Arsenic

Threats due to insufficient, inadequate and costlier methods of treating contaminants such as arsenic have emphasized the significance of optimizing and managing the processes adopted. This study was aimed at the complete elimination of arsenic from an aqueous medium with minimum energy consumption using the electrocoagulation process. Arsenic removal around 95% was rapidly attained for optimized conditions having a pH of 7, 0.46 A current intensity, 10 mg/L initial concentration and only 2 min of applied time duration using the energy of 3.1 watt-hour per gram of arsenic removed. Low values of applied current for longer durations resulted in the complete removal of arsenic with low energy consumption. Various hydroxide complexes including ferrous hydroxide and ferric hydroxide assisted in the removal of arsenic by adsorption along with co-precipitation. Surface models obtained were checked and found with a reasonably good fit having high values of coefficient of determination of 0.933 and 0.980 for removal efficiency and energy consumption, respectively. Adsorption was found to follow pseudo-first-order kinetics. Multivariate optimization proved it as a low-cost effective technology having an operational cost of 0.0974 Indian rupees (equivalent to USD 0.0013) per gram removal of arsenic. Overall, the process was well optimized using CCD based on response surface methodology.

scholarly journals Pick’s Tau Fibril Shows Multiple Distinct PET Probe Binding Sites: Insights from Computational Modelling

2020 ◽  
Vol 22 (1) ◽  
pp. 349
Author(s):  
Sushil K. Mishra ◽  
Yoshiki Yamaguchi ◽  
Makoto Higuchi ◽  
Naruhiko Sahara
Keyword(s):  
Binding Sites ◽  
Rational Design ◽  
Computational Modelling ◽  
Binding Energies ◽  
Pick's Disease ◽  
Pick’S Disease ◽  
Binding Modes ◽  
Surface Binding ◽  
Pet Tracers ◽  
Age Related

In recent years, it has been realized that the tau protein is a key player in multiple neurodegenerative diseases. Positron emission tomography (PET) radiotracers that bind to tau filaments in Alzheimer’s disease (AD) are in common use, but PET tracers binding to tau filaments of rarer, age-related dementias, such as Pick’s disease, have not been widely explored. To design disease-specific and tau-selective PET tracers, it is important to determine where and how PET tracers bind to tau filaments. In this paper, we present the first molecular modelling study on PET probe binding to the structured core of tau filaments from a patient with Pick’s disease (TauPiD). We have used docking, molecular dynamics simulations, binding-affinity and tunnel calculations to explore TauPiD binding sites, binding modes, and binding energies of PET probes (AV-1451, MK-6240, PBB3, PM-PBB3, THK-5351 and PiB) with TauPiD. The probes bind to TauPiD at multiple surface binding sites as well as in a cavity binding site. The probes show unique surface binding patterns, and, out of them all, PM-PBB3 proves to bind the strongest. The findings suggest that our computational workflow of structural and dynamic details of the tau filaments has potential for the rational design of TauPiD specific PET tracers.

Sign in / Sign up

Export Citation Format

Share Document