scholarly journals Immobilization of 60Co and 90Sr ions using red mud from aluminum industry

2014 ◽  
Vol 29 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Aleksandra Milenkovic ◽  
Ivana Smiciklas ◽  
Jelena Markovic ◽  
Nikola Vukelic
Keyword(s):  
Red Mud ◽  
High Efficiency ◽  
Low Cost ◽  
Water Desorption ◽  
Sorption Data ◽  
Fine Grained ◽  
Pollutant Concentrations ◽  
Ore Processing ◽  
Maximum Sorption ◽  
Initial Ph

The removal of 60Co and 90Sr from the aqueous phase was tested using red mud - the fine grained residue from bauxite ore processing. This industrial waste represents a mixture of numerous minerals, mainly oxides and hydroxides of Fe, Al, Si, and Ti. Experiments were conducted as a function of contact time, pH, and pollutant concentrations. Kinetic data were well fitted with a pseudo-second order equation. The calculated rate constants and initial sorption rates indicated faster sorption of Sr2+ ions. Removal of both cations rapidly increased with the initial pH increase from 2.5 to 3.5. With the further increase of pH, Co2+ sorption was nearly constant (98%-100%), whereas Sr2+ removal remained at the same level to initial pH ~8 and gradually increased to 100% at pH 12. Equilibrium sorption data followed the Langmuir model, with the maximum sorption capacities of 0.52 mmol/g for Co2+ and 0.31 mmol/g for Sr2+. Sorbed cations exhibited high stability in distilled water. Desorption of Co2+ was also negligible in the presence of the competing Ca2+ cation, while 42%-25% of Sr2+ ions were desorbed depending on the previously sorbed amount. The results indicate that red mud is of potential significance as Co2+ and Sr2+ immobilization agent due to its high efficiency, abundance, and low-cost.

scholarly journals Red Mud-Based Polyaluminum Ferric Chloride Flocculant: Preparation, Characterization and Flocculation Performance

2021 ◽  
Author(s):  
Yong Cheng ◽  
Longjun Xu ◽  
Chenglun Liu ◽  
Zao Jiang ◽  
Qiyuan Zhang ◽  
...  
Keyword(s):  
Red Mud ◽  
High Efficiency ◽  
Low Cost ◽  
Oxygen Demand ◽  
Industrial Applications ◽  
Iron Chloride ◽  
Raw Material ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
Solution Ph

Abstract In this work, red mud was used as raw material to extract Al and Fe with hydrochloric acid. The high-efficiency polyaluminum iron chloride (PAFC) flocculant was prepared via adjusting the pH of the leaching solution, the molar ratio of aluminum and iron, and the polymerization temperature. The effect of synthesis and flocculation conditions on the flocculation performance of aged landfill leachate was investigated. The results confirmed that the PAFC prepared at the polymerization pH of 2.5, the Al/Fe molar ratio of 8, and the polymerization temperature of 70 °C had the optimum flocculation effect. The flocculation consequences of PAFC and commercial polyaluminum iron chloride flocculant (CPAFC) under different flocculation conditions were compared. The chemical oxygen demand (COD), UV254, chroma and settlement height of PAFC at flocculant concentration of 60 g/L and solution pH of 6 were 72.2%, 79.2%, 82.9% and 9.5 cm (within 90 min), respectively. PAFC has excellent flocculation performance and can be used as a simple, potentially low-cost wastewater treatment agent in industrial applications.

scholarly journals Sorption of cationic dyes from aqueous solutions by moss Rhytidiadelphus squarrosus: Kinetics and equilibrium studies

2021 ◽  
Vol 9 (1) ◽  
pp. 53-62
Author(s):  
Lucia Remenárová ◽  
Martin Pipíška ◽  
Miroslav Horník ◽  
Jozef Augustín
Keyword(s):  
Aqueous Solutions ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Cationic Dyes ◽  
Order Kinetic ◽  
Natural Sorbent ◽  
Equilibrium Studies ◽  
Sorption Data ◽  
Maximum Sorption ◽  
Rhytidiadelphus Squarrosus

With the aim to investigate sorption properties of natural sorbent prepared from moss Rhytidiadelphus squarrosus we elucidated biosorption of cationic dyes Malachite green (BG4), Auramine O (BY2) and Thioflavine T (BY1) from aqueous solutions. The removal of dyes by moss biosorbent was found to be rapid at an initial stage and the equilibrium was reached within 1-2 hours. The pseudo-n-order kinetic model was successfully applied to the kinetic data and the order of adsorption reaction was calculated in the range from 1.7 to 2.6. The value of rate constant kn' ranged from 0.001 to 0.039 [min-1]/[μmol/g]1-n. The equilibrium data were fitted to the adsorption isotherms. The Freundlich isotherm was found to represent the measured sorption data of BG4, BY1 and BY2 well. The maximum sorption capacities of moss biomass from single dye solutions calculated by Langmuir equation were 354 μmol/g for BG4, 310 μmol/g for BY1 and 382 μmol/g for BY2. These results showed that the prepared biomass presents low-cost, natural and easy available sorbent which may be potentially used for removal of dyes from environment and also may be an alternative to more costly materials such as activated carbon.

scholarly journals Ni(II) immobilization by bio-apatite materials: Appraisal of chemical, thermal and combined treatments

2016 ◽  
Vol 22 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Marija Sljivic-Ivanovic ◽  
Aleksandra Milenkovic ◽  
Mihajlo Jovic ◽  
Slavko Dimovic ◽  
Ana Mrakovic ◽  
...  
Keyword(s):  
Organic Phase ◽  
High Efficiency ◽  
Calcium Hydroxyapatite ◽  
Organic Content ◽  
Sorption Data ◽  
Animal Bones ◽  
Maximum Sorption ◽  
Sequential Extraction Analysis ◽  
Contamination Levels ◽  
The Stability

Animal bones are natural and rich source of calcium hydroxyapatite (HAP), which was found to be a good sorbent material for heavy metals and radionuclides. Various treatments can reduce the content of bone organic phase and improve sorption properties. In this study, sorption capacities of raw bovine bones (B) and samples obtained by chemical treatment with NaOH (BNaOH), by heating at 400 oC (B400) and by combined chemical and thermal treatment (BNaOH+400), were compared, using Ni(II) ions as sorbates. Maximum sorption capacities increased in the order B<BNaOH<B400<BNaOH+400. Based on different sorption data and FT-IR analyses, the mechanism of Ni(II) sorption was found to be complex, with participation of both HAP and organic phase (when present). Sequential extraction analysis was applied for testing the stability of Ni(II) ions sorbed by BNaOH+400. Majority of Ni(II) was found in residual phase (65%) at lower level of sorbent loading, while with the increase of sorbent saturation carbonate fraction became dominant (39 %). According to the results, BNaOH+400 can be utilized in water purification systems. As an apatite based material with low organic content and high efficiency for Ni(II) sorption, it is also a good candidate for in-situ soil remediation, particularly at lower contamination levels.

scholarly journals A Review on Comprehensive Utilization of Red Mud and Prospect Analysis

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 362 ◽  
Author(s):  
Li Wang ◽  
Ning Sun ◽  
Honghu Tang ◽  
Wei Sun
Keyword(s):  
Red Mud ◽  
High Efficiency ◽  
New Technologies ◽  
Low Cost ◽  
Environmental Benefits ◽  
Future Research ◽  
Environmental Damage ◽  
Efficient Technology ◽  
Environmental Application ◽  
Comprehensive Utilization

Red mud (RM) is a by-product of extracting of alumina from bauxite. Red mud contains high quantities of alkali-generating minerals and metal ions, which can cause significant environmental damage. Many valuable components such as rare-earth elements, Al, and Fe, in RM are difficult to be utilized owing to their particle size and alkalinity. Thus, developing an economical and efficient technology to consume a large amount of RM can efficiently solve RM disposal issues. This paper systematically reviews the comprehensive utilization methods for reducing RM environmental pollution and divides the comprehensive utilization of RM into three aspects: the effective extraction of valuable components, resource transformation, and environmental application. Based on resource, economic, and environmental benefits, the development of new technologies and new processes with market competitiveness, environmental protection, and ecological balance should be the prerequisite for the low-energy, low-pollution, low-cost, and high-efficiency comprehensive utilization of RM. The direction of future research to solve RM disposal issues is also suggested.

Biosorption of Strontium Ions by Low-Cost Sunflower Stem and Leaf

2014 ◽  
Vol 804 ◽  
pp. 59-62
Author(s):  
Lian Ai ◽  
Xue Gang Luo ◽  
Xiao Yan Lin
Keyword(s):  
Low Cost ◽  
Solution Ph ◽  
Maximum Sorption Capacity ◽  
Adsorption Data ◽  
Maximum Sorption ◽  
Initial Ph ◽  
Isotherm Adsorption ◽  
Strontium Ions ◽  
Ph Range ◽  
By Products

Low cost agricultural by-products are potential materials for water pollution treatment such as removal of radionuclide. This paper deals with removal of strontium ions from aqueous solution using sunflower stem (SFS) and leaf (SFL). Batch sorption experiments were performed as a function of initial solution pH, adsorbent dosage and initial strontium (II) concentration. The removal efficiency of strontium (II) increased with initial pH and achieved maximum values at a pH range of 4.0-7.0 both for SFS and SFL. The isotherm adsorption data was modeled best by the nonlinear Langmuir-Freundlich equation. The maximum sorption capacity of SFS and SFL were observed to be 17.87 and 22.31 mg/g under optimal conditions, respectively.

scholarly journals A novel biochar derived from cauliflower (Brassica oleracea L.) roots could remove norfloxacin and chlortetracycline efficiently

2017 ◽  
Vol 76 (12) ◽  
pp. 3307-3318 ◽  
Author(s):  
Tingting Qin ◽  
Zhaowei Wang ◽  
Xiaoyun Xie ◽  
Chaoran Xie ◽  
Junmin Zhu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Energy Dispersive Spectrometer ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Initial Ph ◽  
Intra Particle Diffusion

Abstract The biochar was prepared by pyrolyzing the roots of cauliflowers, at a temperature of 500 °C under oxygen-limited conditions. The structure and characteristics of the biochar were examined using scanning electron microscopy, an energy dispersive spectrometer, a zeta potential analyzer, and Fourier transform infrared spectroscopy. The effects of the temperature, the initial pH, antibiotic concentration, and contact time on the adsorption of norfloxacin (NOR) and chlortetracycline (CTC) onto the biochar were investigated. The adsorption kinetics of NOR and CTC onto the biochar followed the pseudo-second-order kinetic and intra-particle diffusion models. The adsorption isotherm experimental data were well fitted to the Langmuir and Freundlich isotherm models. The maximum adsorption capacities of NOR and CTC were 31.15 and 81.30 mg/g, respectively. There was little difference between the effects of initial solution pH (4.0–10.0) on the adsorption of NOR or CTC onto the biochar because of the buffering effect. The biochar could remove NOR and CTC efficiently in aqueous solutions because of its large specific surface area, abundant surface functional groups, and particular porous structure. Therefore, it could be used as an excellent adsorbent material because of its low cost and high efficiency and the extensive availability of the raw materials.

scholarly journals APPLICATION OF ACID MODIFIED RED MUD FOR LEAD ION REMOVAL FROM AQUEOUS SOLUTION

2018 ◽  
Vol 54 (2A) ◽  
pp. 186
Author(s):  
Pham Thu Trang
Keyword(s):  
Removal Efficiency ◽  
Red Mud ◽  
Contact Time ◽  
Low Cost ◽  
Lead Ion ◽  
Order Kinetic ◽  
Ion Removal ◽  
Metals Removal ◽  
Initial Ph ◽  
Pseudo Second Order

In this study, the Pb(II) adsorption experiments with the single acid modified red mud were conducted as a function of initial pH, adsorbent doses, contact time, initial Pb(II) concentrations, and competitive ions. The adsorption results pointed that the highest Pb(II) removal efficiency was achieved at the initial pH 4.0, adsorbent dose 7.5 g/L, shaking speed 150 rpm and contact time around 60 minutes at the room temperature. The adsorption results arrowed that the Pb(II) removal efficiency of the modified red mud was enhanced to 150% compared to the raw red mud. The adsorption capacity of the modified red was measured of 9.52 mg/g, higher compared to several previous studies using the same method and type of acid. The study also indicated that the Pb(II) adsorption kinetic and isotherm were best described by the Pseudo - second - order kinetic and fitted to linearly transform both Langmuir and Freundlich with correlation coefficient (R2) over 0.99. The data obtained in this study indicated that modified red mud by using acid can be used as an effective and low cost adsorbent for heavy metals removal from wastewater.

scholarly journals Numerical modeling of two-dimensional simulation of groundwater protection from lead using different sorbents in permeable barriers

2019 ◽  
Vol 25 (4) ◽  
pp. 605-613
Author(s):  
Zehraa B. Masood ◽  
Ziad Tark Abd Ali
Keyword(s):  
Activated Carbon ◽  
Low Cost ◽  
Phoenix Dactylifera ◽  
Permeable Reactive Barrier ◽  
Isotherm Models ◽  
Two Dimensional ◽  
Sorption Data ◽  
Reactive Material ◽  
Palm Trees ◽  
Initial Ph

This study is to investigate the possibility of using activated carbon prepared from Iraqi date-pits (ADP) which are produced from palm trees (Phoenix dactylifera L.) as low-cost reactive material in the permeable reactive barrier (PRB) for treating lead (Pb<sup>+2</sup>) from the contaminated groundwater, and then compare the results experimentally with other common reactive materials such as commercial activated carbon (CAC), zeolite pellets (ZP). Factors influencing sorption such as contact time, initial pH of the solution, sorbent dosage, agitation speed, and initial lead concentration has been studied. Two isotherm models were used for the description of sorption data (Langmuir and Freundlich). The maximum lead sorption capacities were measured for ADP, CAC, and ZP and were found to be 24.5, 12.125, and 4.45 mg/g, respectively. The kinetic data were analyzed using various kinetic models particularly pseudo-first-order, pseudo-second-order, and intraparticle diffusion. COMSOL Multiphysics 3.5a depend on finite element procedure was applied to formulate transmit of lead (Pb<sup>+2</sup>) in the two-dimensional numerical (2D) model under an equilibrium condition. The numerical solution shows that the contaminant plume is hindered by PRB.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

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