Adsorption Capacities of Iron Hydroxide for Arsenate and Arsenite Removal from Water by Chemical Coagulation: Kinetics, Thermodynamics and Equilibrium Studies

Arsenic (As)-laden wastewater may pose a threat to biodiversity when released into soil and water bodies without treatment. The current study investigated the sorption properties of both As(III, V) oxyanions onto iron hydroxide (FHO) by chemical coagulation. The potential mechanisms were identified using the adsorption models, ζ-potential, X-ray diffraction (XRD) and Fourier Transform Infrared Spectrometry (FT-IR) analysis. The results indicate that the sorption kinetics of pentavalent and trivalent As species closely followed the pseudo-second-order model, and the adsorption rates of both toxicants were remarkably governed by pH as well as the quantity of FHO in suspension. Notably, the FHO formation was directly related to the amount of ferric chloride (FC) coagulant added in the solution. The sorption isotherm results show a better maximum sorption capacity for pentavalent As ions than trivalent species, with the same amount of FHO in the suspensions. The thermodynamic study suggests that the sorption process was spontaneously exothermic with increased randomness. The ζ-potential, FT-IR and XRD analyses confirm that a strong Fe-O bond with As(V) and the closeness of the surface potential of the bonded complex to the point of zero charge (pHzpc) resulted in the higher adsorption affinity of pentavalent As species than trivalent ions in most aquatic conditions. Moreover, the presence of sulfates, phosphates, and humic and salicylic acid significantly affected the As(III, V) sorption performance by altering the surface properties of Fe precipitates. The combined effect of charge neutralization, complexation, oxidation and multilayer chemisorption was identified as a major removal mechanism. These findings may provide some understanding regarding the fate, transport and adsorption properties onto FHO of As oxyanions in a complex water environment.

Download Full-text

Removal of Cd2+ from Water by Use of Super-Macroporous Cryogels and Comparison to Commercial Adsorbents

Polymers ◽

10.3390/polym12102405 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2405

Author(s):

Alzhan Baimenov ◽

Dmitriy Berillo ◽

Seitkhan Azat ◽

Talgat Nurgozhin ◽

Vassilis Inglezakis

Keyword(s):

Zeolite Y ◽

Tap Water ◽

Cation Exchange Resin ◽

Experimental Conditions ◽

Equilibrium Studies ◽

Maximum Sorption Capacity ◽

Physico Chemical ◽

Maximum Sorption ◽

Ft Ir ◽

The Stability

In this study amphoteric cryogels were synthesized by the use of free-radical co-polymerization of acrylate-based precursors (methacrylic acid and 2-acrylamido-2-methyl-1-propansulfonic acid) with allylamine at different ratios. The physico-chemical characteristics of the cryogels were examined using SEM/EDX, FT-IR, XPS and zeta potential measurements. The cryogels were tested toward Cd2+ removal from aqueous solutions at various pH and initial concentrations. Equilibrium studies revealed a maximum sorption capacity in the range of 132–249 mg/g. Leaching experiments indicated the stability of Cd2+ in the cryogel structure. Based on kinetics, equilibrium and characterization results, possible removal mechanisms are proposed, indicating a combination of ion exchange and complexation of Cd2+ with the cryogels’ surface functional groups. The cryogels were compared to commercially available adsorbents (zeolite Y and cation exchange resin) for the removal of Cd2+ from various water matrices (ultrapure water, tap water and river water) and the results showed that, under the experimental conditions used, the cryogels can be more effective adsorbents.

Download Full-text

Removal of Arsenic Oxyanions from Water by Ferric Chloride—Optimization of Process Conditions and Implications for Improving Coagulation Performance

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18189812 ◽

2021 ◽

Vol 18 (18) ◽

pp. 9812

Author(s):

Muhammad Ali Inam ◽

Rizwan Khan ◽

Kang-Hoon Lee ◽

Young-Min Wie

Keyword(s):

Drinking Water ◽

Ferric Chloride ◽

Iron Hydroxide ◽

Operating Conditions ◽

Effect Of Temperature ◽

Optimum Operating ◽

Process Conditions ◽

As Species ◽

Adsorption Affinity ◽

Optimum Ph

The chronic ingestion of arsenic (As) contaminated water has raised significant health concerns worldwide. Iron-based coagulants have been widely used to remove As oxyanions from drinking water sources. In addition, the system’s ability to lower As within the maximum acceptable contamination level (MCL) is critical for protecting human health from its detrimental effects. Accordingly, the current study comprehensively investigates the performance of As removal under various influencing factors including pH, contact time, temperature, As (III, V) concentration, ferric chloride (FC) dose, and interfering ions. The optimum pH for As (V) removal with FC was found to be pH 6–7, and it gradually decreased as the pH increased. In contrast, As (III) removal increased with an increase in pH with an optimum pH range of 7–10. The adsorption of As on precipitated iron hydroxide (FHO) was better fitted with pseudo-second order and modified Langmuir–Freundlich models. The antagonistic effect of temperature on As removal with FC was observed, with optimum temperature of 15–25 °C. After critically evaluating the optimum operating conditions, the uptake indices of both As species were developed to select appropriate an FC dose for achieving the MCL level. The results show that the relationship between residual concentration, FC dose, and adsorption affinity of the system was well represented by uptake indices. The higher FC dose was required for suspensions containing greater concentration of As species to achieve MCL level. The As (V) species with a greater adsorption affinity towards FHO require a relatively smaller FC dose than As (III) ions. Moreover, the significant influence of interfering species on As removal was observed in simulated natural water. The author hopes that this study may help researchers and the drinking water industry to develop uptake indices of other targeted pollutants in achieving MCL level during water treatment operations in order to ensure public health safety.

Download Full-text

Phosphate Removal Using Polyethylenimine Functionalized Silica-Based Materials

Sustainability ◽

10.3390/su13031502 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1502

Author(s):

Maria Xanthopoulou ◽

Dimitrios Giliopoulos ◽

Nikolaos Tzollas ◽

Konstantinos S. Triantafyllidis ◽

Margaritis Kostoglou ◽

...

Keyword(s):

Sorption Capacity ◽

Removal Rate ◽

Phosphate Concentration ◽

Phosphate Removal ◽

Equilibrium Studies ◽

Maximum Sorption Capacity ◽

Algae Blooms ◽

Maximum Sorption ◽

Phosphate Anions ◽

Adsorbent Dose

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems.

Download Full-text

Magnetic Nanoparticles Derivatized with Dual Functional Groups for Environmental Applications

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.148-149.949 ◽

2010 ◽

Vol 148-149 ◽

pp. 949-952

Author(s):

Hai Bo He ◽

Qing Zhong Guo

Keyword(s):

Magnetic Nanoparticles ◽

Environmental Remediation ◽

Infrared Spectrometry ◽

X Ray Diffraction ◽

Water Contact ◽

Dual Functional ◽

New Material ◽

Ft Ir ◽

Contact Angle Analysis ◽

Effective Sorbent

In this study, the magnetic nanoparticles derivatized with dual functional moieties of dodecyl and mercapto were prepared, which characterized by X-ray diffraction (XRD), scanning electron microscope(SEM), surface area and pore size determination, fourier transform infrared spectrometry (FT-IR) and water contact angle analysis. The new material was proved to be an effective sorbent for environmental remediation.

Download Full-text

Study on Modified Rapeseed Oil/Montmorillonite Nanocomposites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.123-125.1291 ◽

2010 ◽

Vol 123-125 ◽

pp. 1291-1294 ◽

Cited By ~ 1

Author(s):

Bin Lü ◽

Jian Zhong Ma ◽

Dang Ge Gao ◽

Lei Hong

Keyword(s):

Rapeseed Oil ◽

Fourier Transforms ◽

Raw Materials ◽

Infrared Spectrometry ◽

Emulsifying Properties ◽

X Ray Diffraction ◽

Layer Spacing ◽

Transmission Electron ◽

Ft Ir ◽

Better Than

Modified rapeseed oil(MRO) was prepared by using rapeseed oil, ethylene diamine and acrylic acid as the raw materials. Modified rapeseed oil/montmorillonite(MRO/MMT) nanocomposite was prepared by using modified rapeseed oil and montmorillonite. The emulsifying properties of MRO and MRO/MMT were determined respectively. Fourier transforms infrared spectrometry (FT-IR) and Transmission Electron microscope (TEM) results showed that MRO/MMT was prepared successfully. X-ray diffraction (XRD) results showed that modified rapeseed oil could smoothly enter the interlayer of montmorillonite, and modified the montmorillonite; with an increase in the amount of montmorillonite, the layer spacing of montmorillonite in the MRO/MMT lower after the first increase. The results of emulsifying properties indicated that emulsifying properties of MRO/MMT was better than MRO.

Download Full-text

Synthesis characterization and sorption properties of a sorbent synthesized using slag and red mud: Arsenic removal from spiked aqueous solutions

Global NEST Journal ◽

10.30955/gnj.001873 ◽

2016 ◽

Vol 18 (2) ◽

pp. 339-347 ◽

Cited By ~ 1

Keyword(s):

Aqueous Solutions ◽

Red Mud ◽

Arsenic Removal ◽

Point Of Zero Charge ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

Equilibrium Studies ◽

Metallurgical Wastes ◽

Bet Method ◽

Gf Aas

<p>The aim of the present study was to synthesize a sorbent, for arsenic removal from aqueous solutions, reusing two waste materials (slag and red mud). The sorbent was prepared after chemical and thermal treatment, during which amorphous silica sol and FeOOH sol were produced simultaneously and form Fe-Si complexes on the surface of the slag. To characterize the sorbent Powder X-ray diffraction (XRD); Fourier transform infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM-EDX) were applied. The surface area (BET method) and the Point of Zero Charge (PZC) of the sorbent were determined.). The sorption efficiency of the sorbent produced was investigated with kinetic and equilibrium studies, performed in batch conditions. The concentration of arsenic in solutions was determined by electro thermal atomic absorption spectroscopy (GF-AAS). The results of the study showed that with the described process, using metallurgical wastes, iron oxyhydroxides were “loaded” onto slag producing an effective sorbent for arsenic removal. Kinetic experiments proved that equilibrium was achieved within 15 hours, while the maximum adsorption capacity as evidenced by equilibrium experiments, was 16.14 mg g<sup>-1</sup>. Data proved to fit better to the Langmuir equation.</p>

Download Full-text

Fabrication of Novel Valorized Ecofriendly Olive Seed Residue/anthracite/chitosan Composite for Removal of Cr (Vi): Kinetics, Isotherms and Thermodynamics Modeling

10.21203/rs.3.rs-179237/v1 ◽

2021 ◽

Author(s):

M R. El-Aassar ◽

F. M. Mohamed ◽

I. H. Alsohaimia ◽

R E. Khalifa

Keyword(s):

Low Cost ◽

Operating Conditions ◽

Batch Adsorption ◽

Adsorption Mode ◽

Adsorption Affinity ◽

Equilibrium Data ◽

Isotherms And Thermodynamics ◽

Olive Seed ◽

Ft Ir ◽

Thermodynamics Modeling

Abstract The present work verified the adsorption of hexavalent chromium (Cr (VI)) from synthetic aqueous solution using synthesized highly efficient low-cost adsorbent prepared from H2O2-modified olive seed residue solid waste/Anthracite/Chitosan (MOSR/An/CS) composite. Characteristics of the fabricated MOSR/An/CS composite were estimated by XRD, SEM, TGA, DSC, FT-IR, SBET and zeta potential tools. The entire chromium uptake study was conducted via batch adsorption mode under various operating conditions. Kinetics data were analyzed using five kinetic models, while empiric equilibrium data was fitted using three isotherms. The results clarified that Langmuir best described the adsorption of Cr (VI) ions with maximum monolayer coverage of 137.7 mg/g. Pseudo-first-order mode was nicely fitted the kinetics adsorption. Further, Elovich, intraparticle diffusion and Boyd models validates that more than one mechanism was contributed to the adsorption of Cr (VI). Besides, the estimated activation energy (Ea) and enthalpy (ΔH°) suggest the physical and endothermic nature of the adsorption process. The developed MOSR/An/Cs composite exhibited decent reusability after five sequential adsorption cycles and showed higher adsorption affinity towards Cr (VI) ions. MOSR / An / Cs composite could also be effectively used as an effective eco-friendly and recyclable sorbent for the elimination of Cr (VI) from wastewater.

Download Full-text

SiCi_xNxthin films preparation by TEA-Co2 Laser induced Vapor-phase reaction and study of the nature of chemical bonds and some their electrical and optical properties

Baghdad Science Journal ◽

10.21123/bsj.1.2.239-246 ◽

2004 ◽

Vol 1 (2) ◽

pp. 239-246

Author(s):

Baghdad Science Journal

Keyword(s):

Optical Properties ◽

Localized States ◽

Infrared Spectrometry ◽

Phase Reaction ◽

Chemical Bonds ◽

Electrical And Optical Properties ◽

Vapor Phase Reaction ◽

Ft Ir ◽

C And N ◽

Deposited Films

A pulsed (TEA-0O2) laser was used to dissociate molecules of silane ethylene (C2I-14) and ammonia (NH3) gases, through collision assisted multiple photon dissociation (MPD) to deposit(SiC i_xNx) thin films, where the X-values are 0, 0.13 and 0.33, on glass substrate at T,----648 K. deposition rate of (0.416-0.833) nm/pulse and thickness of (500-1000)nm .Fourier transform infrared spectrometry (FT-IR) was used to study the nature of the chemical bonds that exist in the films. Results revealed that these films contain complex networks of the atomic (Si, C, and N), other a quantity of atomic hydrogen and chemical bonds such as (Si-N, C-N, C-14 and N-H).Absorbance and Transmittance spectra in the wavelength range (400-1100) nm were used to study the optical properties of the deposited films. It was found the optical nergy ap E0) of these films is indirect and increases with increasing (X) while the width of localized states decreases.The study of the electrical properties of the deposited films revealed that their electrical conductivity at any constant temperature decreases with increasing (X) and the films have two activation energies both increase with increasing (X).

Download Full-text

FT-IR Characterization of the Acidic and Basic Sites on a Nanostructured Aluminum Nitride Surface

MRS Proceedings ◽

10.1557/proc-454-59 ◽

1996 ◽

Vol 454 ◽

Cited By ~ 3

Author(s):

M.-I. Baraton ◽

X. Chen ◽

K. E. Gonsalves

Keyword(s):

Aluminum Nitride ◽

Organic Molecules ◽

Sol Gel ◽

Atomic Layer ◽

Infrared Spectrometry ◽

Nitride Powder ◽

Fourier Transform Infrared Spectrometry ◽

Basic Sites ◽

Ft Ir

ABSTRACTA nanostructured aluminum nitride powder prepared by sol-gel type chemical synthesis is analyzed by Fourier transform infrared spectrometry. The surface acidic and basic sites are probed out by adsorption of several organic molecules. Resulting from the unavoidable presence of oxygen, the aluminum nitride surface is an oxinitride layer in fact, and its surface chemistry should present some analogies with alumina. Therefore, a thorough comparison between the acido-basicity of aluminum nitride and aluminum oxide is discussed. The remaining nitrogen atoms in the first atomic layer modify the acidity-basicity relative balance and reveals the specificity of the aluminum nitride surface.

Download Full-text

Purification, Characterization, and Time-Dependent Adsorption Studies of Ghanaian Muscovite Clay

Journal of Chemistry ◽

10.1155/2018/6252913 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Samuel Tetteh ◽

Andrews Quashie ◽

Michael Akrofi Anang

Keyword(s):

Exchange Capacity ◽

Time Dependent ◽

Point Of Zero Charge ◽

X Ray Diffraction ◽

X Ray ◽

Adsorption Studies ◽

Morphological Studies ◽

Ft Ir ◽

Crystalline Nature ◽

Different Parts

Three clay samples (E1, E2, and C1) extracted from different parts of Ghana have been purified by sedimentation. The samples were further characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), cation exchange capacity (CEC), and point of zero charge (pHpzc). PXRD and FT-IR data revealed the samples to be predominantly muscovite clay with percentages ranging from 82.71 to 91.33%. The surfaces were mostly cationic with pHpzc ranging from 5.58 to 6.40. Morphological studies by SEM confirmed the crystalline nature of the surfaces which is suitable for adsorption studies. Time-dependent adsorption studies show that C1 is a good candidate for the adsorption of chlorophenols, methyl orange, and Eriochrome Black T.

Download Full-text