Efficient Removal of Lead and Cadmium ions by Titanate Nanotubes Prepared at Different Hydrothermal Conditions

2018 ◽  
Vol 15 (2) ◽  
pp. 197-208 ◽  
Author(s):  
Maha A. Alwaili ◽  
Heba Allah M. Elbaghdady ◽  
Ayman H. Zaki ◽  
Mohammed A. Sallam
Keyword(s):  
Electron Microscopy ◽  
Removal Efficiency ◽  
Contact Time ◽  
Titanate Nanotubes ◽  
Bet Surface Area ◽  
Efficient Removal ◽  
Hydrothermal Conditions ◽  
Factors Affecting ◽  
Lead And Cadmium ◽  
Ph Range

Background: Nanotubes serve an important role in heavy metal ions for the removal from wastewater. The efficiency of these nanotubes is dependent on the nature of surface, pH, temperature setting and the hydrothermal contact time. Method: The current research sought to find out the efficiency of titanate nanotubes in the removal of Pb2+ and Cd2+ ions from wastewater. The research concentrated on mesoporosity, pH and hydrothermal contact time, as factors affecting the efficiency of titanate nanotubes in the removal of Pb2+ and Cd2+ ions. Titanate nanotubes were prepared at different hydrothermal conditions, the prepared nanotubes were used for efficient removal of Pb2+ and Cd2+. The following technologies were utilized in the research: (1). electron microscopy (FESEM), (2). X-ray diffraction (XRD), (3). highresolution transmission electron microscopy (HRTEM), (4). FTIR and BET surface area were measured by N2 adsorption using Micrometrics TriStar II. Results: The results obtained reveal that increasing the hydrothermal time improved the adsorption efficiency of the prepared material, where the Titanate nanotubes prepared at the longest time (23hr) achieved the highest removal efficiency for both Pb2+ and Cd2+ at pH 2 and pH 3, respectively. The nanotubes prepared at different conditions also showed significant activities, where the removal % exceeded 90 % for all samples at a pH range of 2 to 3. It was conducted that the factors that affected the efficiency could be set at optimum and the removal efficiency attained be increased, to more than 90%.

Kinetic and structural constraints during glauconite dissolution: implications for mineral disposal of CO2

2008 ◽  
Vol 72 (1) ◽  
pp. 27-31 ◽  
Author(s):  
S. Fernandez-Bastero ◽  
C. Gil-Lozano ◽  
M. J. I. Briones ◽  
L. Gago-Duport
Keyword(s):  
Electron Microscopy ◽  
Batch Reactor ◽  
Bet Surface Area ◽  
Dissolution Mechanism ◽  
Structural Constraints ◽  
X Ray Diffraction ◽  
Ph Values ◽  
Transmission Electron ◽  
Ph Range

AbstractThe kinetics of glauconite dissolution have been determined in the pH range 2—10 (T = 25°C) using flow-batch reactor experiments. Besides the kinetic characteristics, the structural and textural aspects which could influence its long-term reactivity have also been characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and BET surface area measurements. The results from these analyses showed that glauconite follows a dual dissolution pathway which is pH-dependent, being more stable at neutral or slightly alkaline pH values. Under acidic conditions, glauconite is slightly more soluble than other ubiquitous silicates present in the marine sediments. The dissolution mechanism is incongruent at very acid pH values and tends to be congruent for intermediate and neutral ones. In addition, the results from the structural analyses suggest that the dissolution is a two-step process: the first one involves the disorder of the octahedral and tetrahedral layers, probably following a turbostratic mechanism which is evident in the XRD spectra as selective broadening of several reflections. In the second step, the dissolution of the cations from interlayer positions takes place and leads to the formation of an amorphous residue which acts as a passivating layer and reduces the reactive surface considerably. The influence of these aspects on CO2 capture via carbonation reactions is discussed.

Preparation and Characterization of Titanate Nanotubes by Hydrothermal Method

2010 ◽  
Vol 177 ◽  
pp. 82-85
Author(s):  
Zhong Sheng Chen ◽  
Wei Ping Gong ◽  
Teng Fei Chen ◽  
Guo Lin Huang ◽  
Wen Yuan Xu
Keyword(s):  
Surface Area ◽  
Treatment Process ◽  
Hydrothermal Process ◽  
Anatase Tio2 ◽  
Titanate Nanotubes ◽  
Bet Surface Area ◽  
Hydrothermal Conditions ◽  
Bet Specific Surface Area ◽  
Ft Ir

Titanate nanotubes (TNTs) were prepared by treatment of anatase-TiO2 nanoparticles in mild hydrothermal conditions. TNTs were characterized by XRD, TEM, FT-IR and BET specific surface area technique. It was found that nanotubes might be NaxH2-xTi3O7 and were formed during the hydrothermal process, rather than during the treatment process with acid solution. The formation mechanism of TNTs can be explained as 3D→2D→1D. After hydrothermally reacting at 130°C for 48h, the as-prepared products exhibit hollow nanotubes with open ends, more than 100 nm in length, 10 nm in outer diameters, large BET surface area and pore volume, which may lead to potential photocatalysis and absorption application.

Synthesis of Calcium Peroxide Microparticles in Aqueous at Room Temperature and its Application in Heavy Metal Ions Removal from Waste Liquid of COD Determining

2013 ◽  
Vol 864-867 ◽  
pp. 648-653
Author(s):  
Jian Zhai ◽  
Chun Hua Jiang
Keyword(s):  
Heavy Metal ◽  
Reaction Time ◽  
Removal Efficiency ◽  
Contact Time ◽  
Heavy Metal Ions ◽  
Room Temperature ◽  
Efficient Removal ◽  
Calcium Peroxide ◽  
Heavy Metal Ions Removal ◽  
Metal Ions Removal

The calcium peroxide microparticles were synthesized and evaluated as an innovative oxidant to remove Fe (III) and Cr (III) from waste liquid of COD determining samples. The CaO2 microparticles were 0.1-0.3 μm in diameter and the average CaO2 content was 80%. Experiments were performed to investigate the influence of contact time, pH of solution and CaO2 microparticles dosage on the efficiency of Fe (III) and Cr (III) removal. Up to 100.0% and 99.8% removal efficiency for Fe (III) and Cr (III) respectively was obtained by microparticles dosage of 10000 mg/L at 30 min and pH 7.46. It could be concluded that the removal efficiency was enhanced by increasing CaO2 microparticles dosage and reaction time, but decreased by increasing pH. These results suggest that CaO2 microparticles may be used to develop a simple and efficient removal method for waste liquid of COD determining samples.

The Adsorption of Cadmium Ions on Fly Ash Based Geopolymer Particles

2018 ◽  
Vol 766 ◽  
pp. 65-70 ◽  
Author(s):  
Sujitra Onutai ◽  
Takaomi Kobayashi ◽  
Parjaree Thavorniti ◽  
Sirithan Jiemsirilers
Keyword(s):  
Fly Ash ◽  
Removal Efficiency ◽  
Contact Time ◽  
Adsorption Process ◽  
Coal Fly Ash ◽  
Bet Surface Area ◽  
Cadmium Ions ◽  
Initial Concentration ◽  
Removal Capacity ◽  
Waste Coal

Geopolymer particles from waste coal fly ash were prepared in order to investigate adsorption process of Cadmium ions. The aim of the study is to focus on factors which affect adsorption process of heavy metals on geopolymer materials. The raw fly ash was mixed with sodium hydroxide solution and sodium silicate solution. After that geopolymer was cured at 80 °C for 24 hr. The sample was ground and washed until pH=7. The obtained geopolymer particles were dried at 60 oC. The raw materials and geopolymer were characterized. The XRD results showed a highly amorphous structure in obtained geopolymer. The major components of waste coal fly ash and synthesized geopolymer were SiO2, Al2O3, Fe2O3 and CaO. The BET surface area of fly ash and geopolymer particles were 0.83 m2/g and 85.01 m2/g, respectively. The adsorption conditions (initial concentration from 10-120 mg/L, temperature at 25-45 °C, pH of cadmium ions solution from 1-5, 0.02-0.14 g. of geopolymer and contact time for 5-180 min) were studied. From removal efficiency results, synthesized geopolymer had high removal capacity for cadmium ions (Cd2+). At pH 5 of solution, the highest Cd2+ removal capacity was obtained. In addition, the removal efficiency increases with an increasing geopolymer dosage, contact time and a decreasing of Cd2+ initial concentration. Moreover, both Langmuir and Freundlich models were investigated for studying adsorption isotherm. The result showed Langmuir model is more suitable for geopolymer adsorption of cadmium ion in aqueous solution than Freundlich model.

The Malachite Green Biodegradation in Bioreactors on Various pH Domains

2019 ◽  
Vol 70 (8) ◽  
pp. 2996-2999
Author(s):  
Viorel Gheorghe ◽  
Catalina Gabriela Gheorghe ◽  
Andreea Bondarev ◽  
Vasile Matei ◽  
Mihaela Bombos
Keyword(s):  
Malachite Green ◽  
Contact Time ◽  
Dominant Species ◽  
Wastewater Treatment Plants ◽  
Organic Substances ◽  
Biological Degradation ◽  
Growth Promoters ◽  
Ph Values ◽  
Biological Sludge ◽  
Ph Range

In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

scholarly journals Release of toxic methylene blue from water by mesoporous silicalite-1: characterization, kinetics and isotherm studies

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin
Keyword(s):  
Electron Microscopy ◽  
Contact Time ◽  
Dye Removal ◽  
Batch Adsorption ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Adsorption Method ◽  
X Ray ◽  
Ft Ir ◽  
Adsorption Desorption

AbstractIn the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.

scholarly journals Chronic Exposure to Lead and Cadmium in Residents Living near a Zinc Smelter

2021 ◽  
Vol 18 (4) ◽  
pp. 1731
Author(s):  
HyeJeong Jo ◽  
GeunBae Kim ◽  
JunYoung Chang ◽  
Kwan Lee ◽  
ChulWoo Lee ◽  
...  
Keyword(s):  
Health Management ◽  
Control Group ◽  
Exposure Group ◽  
Factors Affecting ◽  
Adverse Health Effects ◽  
Lead And Cadmium ◽  
Exposure Levels ◽  
Male Sex ◽  
Locally Grown ◽  
Cd Exposure

This study aimed to measure lead (Pb) and cadmium (Cd) exposure levels in residents living near a zinc (Zn) smelter in Seokpo-myeon, Bonghwa-gun, South Korea, and identify factors affecting exposure. Residents aged ≥20 years living within 3 km and ≥30 km away from the smelter were classified as the exposure group (n = 549), and the control group (n = 265), respectively. Data were obtained through a questionnaire survey. Blood Pb levels in the exposure group (4.19 µg/dL) were higher than in the control group (2.70 µg/dL). The exposure group (1.32 µg/L) also had higher urinary Cd concentrations than the control group (0.80 µg/L). Male sex, older age, previous work at the smelter, smoking, and proximity to the smelter were associated with higher blood Pb levels on multivariate analysis; urinary Cd concentration was significantly higher in women, those who were older, those with experience of working in a Zn smelter or mine, those with proximity to the Zn smelter, and those who consumed locally grown vegetables. In conclusion, Zn smelters are major source of Pb and Cd pollution and require ongoing public health management to prevent potential adverse health effects.

scholarly journals Magnetically Recyclable Wool Keratin Modified Magnetite Powders for Efficient Removal of Cu2+ Ions from Aqueous Solutions

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1068
Author(s):  
Xinyue Zhang ◽  
Yani Guo ◽  
Wenjun Li ◽  
Jinyuan Zhang ◽  
Hailiang Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Ion Concentration ◽  
Bet Surface Area ◽  
Chemical Compositions ◽  
Ion Adsorption ◽  
X Ray ◽  
Wool Keratin

The treatment of wastewater containing heavy metals and the utilization of wool waste are very important for the sustainable development of textile mills. In this study, the wool keratin modified magnetite (Fe3O4) powders were fabricated by using wool waste via a co-precipitation technique for removal of Cu2+ ions from aqueous solutions. The morphology, chemical compositions, crystal structure, microstructure, magnetism properties, organic content, and specific surface area of as-fabricated powders were systematically characterized by various techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), thermogravimetric (TG) analysis, and Brunauer–Emmett–Teller (BET) surface area analyzer. The effects of experimental parameters such as the volume of wool keratin hydrolysate, the dosage of powder, the initial Cu2+ ion concentration, and the pH value of solution on the adsorption capacity of Cu2+ ions by the powders were examined. The experimental results indicated that the Cu2+ ion adsorption performance of the wool keratin modified Fe3O4 powders exhibited much better than that of the chitosan modified ones with a maximum Cu2+ adsorption capacity of 27.4 mg/g under favorable conditions (0.05 g powders; 50 mL of 40 mg/L CuSO4; pH 5; temperature 293 K). The high adsorption capacity towards Cu2+ ions on the wool keratin modified Fe3O4 powders was primarily because of the strong surface complexation of –COOH and –NH2 functional groups of wool keratins with Cu2+ ions. The Cu2+ ion adsorption process on the wool keratin modified Fe3O4 powders followed the Temkin adsorption isotherm model and the intraparticle diffusion and pseudo-second-order adsorption kinetic models. After Cu2+ ion removal, the wool keratin modified Fe3O4 powders were easily separated using a magnet from aqueous solution and efficiently regenerated using 0.5 M ethylene diamine tetraacetic acid (EDTA)-H2SO4 eluting. The wool keratin modified Fe3O4 powders possessed good regenerative performance after five cycles. This study provided a feasible way to utilize waste wool textiles for preparing magnetic biomass-based adsorbents for the removal of heavy metal ions from aqueous solutions.

scholarly journals Surface Texture of Microcrystalline Tunnel-Structured Manganese(IV) Oxides: Nitrogen Sorptiometry and Electron Microscopy Studies

2002 ◽  
Vol 20 (7) ◽  
pp. 619-632 ◽  
Author(s):  
A.A. Ali ◽  
F.A. Al-Sagheer ◽  
M.I. Zaki
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Surface Texture ◽  
Particle Morphology ◽  
High Resolution Electron Microscopy ◽  
Surface Chemical ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Surface Chemical Composition ◽  
Resolution Electron

Three different modifications of manganese(IV) oxide, viz. cryptomelane, nsutite and todorokite-like, were synthesized by hydrothermal methods. The bulk chemical composition, phase composition, crystalline structure and particle morphology of the resulting materials were determined by thermogravimetry, atomic absorption spectroscopy, X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The surface chemical composition, texture and structure were assessed using X-ray photoelectron microscopy, nitrogen sorptiometry and high-resolution electron microscopy. The results highlighted the hydrothermal conditions under which such tunnel-structured modifications of manganese(IV) oxide can be successfully synthesized. Moreover, they revealed that (i) the bulk was microcrystalline, (ii) the crystallites were either fibrils (cryptomelane and nsutite) or rod-like (todorokite) with low-index exposed facets, (iii) the surface chemical composition mostly reflected that of the bulk and (iv) the surface texture was linked with high specific areas, slit-shaped mesopores associated with particle interstices and micropores which allowed surface accessibility to the bulk tunnels of the test oxides. The application of such test oxides as shape-selective oxidation catalysts appears worthy of investigation.

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