Adsorptive removal of trace oxytetracycline from water by acid-modified zeolite: influencing factors

2013 ◽  
Vol 68 (11) ◽  
pp. 2473-2478 ◽  
Author(s):  
Wenhao An ◽  
Hua Xiao ◽  
Man Yu ◽  
Xiaoyang Chen ◽  
Yuxin Xu ◽  
...  
Keyword(s):  
Humic Acid ◽  
Removal Efficiency ◽  
Natural Zeolite ◽  
Opposite Effect ◽  
Swine Wastewater ◽  
Adsorption Efficiency ◽  
Tetracycline Antibiotics ◽  
Modified Zeolite ◽  
Alkaline Conditions ◽  
Acidic Conditions

Because of the wide use of antibiotics in the livestock industry, trace tetracycline antibiotics are frequently detected in swine wastewater and water bodies near pig farms. Based on natural zeolite, modified zeolite was synthesized by treatment with nitric acid. As one kind of typical tetracyclines, oxytetracycline (OTC) was chosen as the target adsorbate. Removal of trace OTC by modified zeolite and the effects of several main water matrices on OTC adsorption were studied in detail. OTC removal efficiency by acid-modified zeolite was about 90%, compared to less than 20% by natural zeolite. In general, in acidic conditions the removal efficiency of OTC by modified zeolite was about 90%, which was much higher than 20–35% in alkaline conditions. An increase in ionic strength from 0.01 to 1.0 M led to a decrease in adsorption efficiency from 90 to 27%. The presence of 10.0 mg L−1 dissolved humic acid accelerated sorption of OTC on modified zeolite, while 100.0 mg L−1 humic acid resulted in the opposite effect. An increase in temperature contributed to enhancing the adsorption efficiency.

scholarly journals An Experimental Study of Fluoride Removal from Wastewater by Mn-Ti Modified Zeolite

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3343
Author(s):  
Bo Yang ◽  
Guirong Sun ◽  
Bingxu Quan ◽  
Jiawei Tang ◽  
Chunhui Zhang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Removal Efficiency ◽  
Natural Zeolite ◽  
Fluoride Concentration ◽  
Current Work ◽  
Fluoride Removal ◽  
Metal Fluoride ◽  
Modified Zeolite ◽  
X Ray ◽  
Independent Variables

The emerging interest in fluoride-removal from wastewater has attracted attention to zeolite since it has been considered as a natural adsorbent. However, the fluoride-removal efficiency of natural zeolite is generally low. As part of the effort to improve the zeolite adsorption efficiency, we have produced and tested the Mn-Ti modified zeolite. In the current work, the material preparation is discussed, and prepared materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy, and Fourier transform infrared (FTIR) spectra. Both static and dynamic experiments were conducted to examine the effects of independent variables. In the static adsorption section, sensitivity analysis experiments were conducted for independent variables, such as adsorbent dosage, pH, temperature, and competitive ions. The maximum adsorption capacity is 2.175 mg/g, which was obtained at PH = 7, temperature = 25 °C, and initial fluoride concentration = 10 mg/L. For adsorption kinetics, both Lagergren and Pseudo-second order models predict the experiments very well, which probably demonstrates that the current process is a combination of physical sorption and chemisorption. For adsorption isotherms, the Freundlich model performs better than the Langmuir model since it is usually applied to illustrate adsorption on inhomogeneous surfaces. In the dynamic adsorption section, sensitivity analysis experiments were also conducted for independent variables, such as adsorbent thickness, flow velocity, initial fluoride concentration, and PH. Additionally, the adsorption mechanism is also discussed. The main reason is the hydrated metal fluoride precipitate formation. As we know, the current work provides the first quantified comparison of the natural zeolite and the Mn-Ti modified zeolite regarding fluoride-removal efficiency.

Removal of Vat Dyes from Textile Wastewater Using Biosludge

2004 ◽  
Vol 39 (3) ◽  
pp. 276-284 ◽  
Author(s):  
Suntud Sirianuntapiboon ◽  
Weerapong Saengow
Keyword(s):  
Removal Efficiency ◽  
Batch Reactor ◽  
Treatment Plant ◽  
Textile Wastewater ◽  
Solid Retention Time ◽  
Adsorption Ability ◽  
Vat Dyes ◽  
Different Types ◽  
Alkaline Conditions ◽  
Acidic Conditions

Abstract Biosludge from a wastewater treatment plant was able to adsorb colourants, particularly vat dyes, from textile wastewater. Autoclaved and resting biosludge showed different adsorption abilities with different types of vat dyes. The adsorption ability of the biosludge increased with an increase in sludge age (solid retention time; SRT). Autoclaved biosludge showed the highest adsorption ability under acidic conditions (pH 3) while the resting biosludge showed the highest adsorption ability under neutral or weak alkaline conditions. The maximum colourant (Vat Black 25) adsorption capacities of autoclaved and resting biosludge with a sludge age of 24 days were 85.54 ± 0.5 and 37.59 ± 0.6 mg/g biosludge, respectively. Using a sequencing batch reactor (SBR) system, the biosludge was able to remove both organic matter and colourants from both textile and synthetic textile wastewaters. The removal efficiencies of the system increased with an increase in SRT of the system. The removal efficiency of the system with textile wastewater was lower than with synthetic textile wastewater. The BOD5 and colourant removal efficiency of the SBR system with textile and synthetic textile industrial wastewaters under a BOD5 loading of 0.13 kg BOD/m3-d were 70.1 ± 4.4% and 84.9 ± 2.0%, and 98.1 ± 1.5% and 87.5 ± 5.1%, respectively.

The microstructure of humic acid-montmorillonite composites

Clay Minerals ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 347-354 ◽  
Author(s):  
H. Ohashi ◽  
H. Nakazawa
Keyword(s):  
Humic Acid ◽  
Silicate Layer ◽  
X Ray Diffraction ◽  
Thin Foils ◽  
Transmission Electron ◽  
Large Organic Molecule ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
The Difference ◽  
Diffraction Patterns

AbstractAn organo-clay composite was prepared by contacting Na-montmorillonite and humic acid in aqueous solution which was of variable pH. After freeze-drying the precipitate of the solution, the detailed structure of the humic acid-montmorillonite composite was observed. Transmission electron micrographs and electron diffraction patterns indicate that the composite which was formed under acidic conditions has a characteristic microstructure. Humic acid, a large organic molecule, is combined with bent or curled thin foils of montmorillonite to form a spherical aggregate. The X-ray diffraction pattern supports this observation and suggests that the montmorillonite is cleaved into thin flakes as a silicate layer. The composite formed under alkaline conditions was in the form of a thin plate or lath and had a similar morphology to that of montmorillonite. The difference in the microstructure of the composite is reasonably attributed to the chemical flexibility of humic acid, i.e., conformation changes depending on the pH of the solution.

ION Exchange Characterisation of Modified Zeolite

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2269-2272 ◽  
Author(s):  
Š Cerjan-Stefanovic ◽  
M. Kaštelan-Macan ◽  
T. Filipan
Keyword(s):  
Drinking Water ◽  
Ion Exchange ◽  
Anion Exchange ◽  
Natural Zeolite ◽  
Deionized Water ◽  
Isomorphous Substitution ◽  
Waste Waters ◽  
Modified Zeolite ◽  
Water Drinking

Isomorphous substitution of phosphorus into a natural zeolite affords the possibility to change the overall framework charge from negative to positive. The substances so created should be used for purification of waste waters. The work describes the preparation of phosphated zeolite, their characterisation and examples of their anion exchange of NO3 on observed in deionized water, drinking water and in the solution containing varying amounts of nitrate.

Kinetics and Removal Efficiency of Nitrogen in Constructed Wetlands Cultivated with Different Plant Species for Treating Swine Wastewater Applied at Different Rates

2021 ◽  
Vol 232 (1) ◽  
Author(s):  
Fátima Resende Luiz Fia ◽  
Antonio Teixeira de Matos ◽  
Ronaldo Fia ◽  
Mateus Pimentel de Matos ◽  
Alisson Carraro Borges ◽  
...  
Keyword(s):  
Plant Species ◽  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Swine Wastewater

Removal of humic acid from aqueous solution by cetylpyridinium bromide modified zeolite

2010 ◽  
Vol 22 (9) ◽  
pp. 1327-1334 ◽  
Author(s):  
Yanhui Zhan ◽  
Zhiliang Zhu ◽  
Jianwei Lin ◽  
Yanling Qiu ◽  
Jianfu Zhao
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Cetylpyridinium Bromide ◽  
Modified Zeolite

Ethylene production via ethanol dehydration over desilicated ZSM-5 catalyst

2021 ◽  
Vol 10 (4) ◽  
pp. 75-79
Author(s):  
Loc Bui Tan ◽  
Tu Le Nguyen Quang ◽  
Long Nguyen Quang
Keyword(s):  
Ethylene Production ◽  
Fossil Fuels ◽  
Opposite Effect ◽  
External Surface ◽  
Space Velocity ◽  
Ethanol Conversion ◽  
Ethanol Dehydration ◽  
Modified Zeolite ◽  
Potential Alternative ◽  
Lower Temperature

The catalytic dehydration of ethanol is a potential alternative route to synthesize ethylene apart from the traditional method which depends on fossil fuels. This report successfully prepared modified ZSM-5 with mesopores using desilication methods to enhance ethanol catalytic dehydration performance and ethylene production at lower temperature. The modified zeolite have the external surface area increased by 3.5 times and a higher dehydration efficiency compared with the original sample especially at temperatures below 220°C. Increasing reaction temperatures and gas houly space velocity (GHSV) increased the dehydration efficiency while increasing the inlet ethanol concentration had opposite effect. Significantly, the ethanol conversion over modified zeolite remained above 90 % when the GHSV increased to 36000 h‑1 after the time-on-stream of 24 h.

scholarly journals Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Ph Value ◽  
Batch Experiments ◽  
Modified Zeolite ◽  
Optimum Ph ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Correlation Factors ◽  
Maximum Removal

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.

Effect of acidity on the properties of silica-aluminas synthesized by sol-gel method

2020 ◽  
Vol 63 (7) ◽  
pp. 126-132
Author(s):  
Lyubov V. Furda ◽  
◽  
Evgenia A. Tarasenko ◽  
Sofya N. Dudina ◽  
Olga E. Lebedeva ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Molar Ratio ◽  
Active Centers ◽  
Indicator Method ◽  
Synthesis Conditions ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Amphoteric Properties ◽  
Hydrolysis Of

In the present work amorphous silica-aluminas were synthesized by the coprecipitation method during the hydrolysis of an alcohol solution of tetraethoxysilane (with a tetraethoxysilane: alcohol mass ratio of 1: 1) and 6% aqueous solution of aluminum nitrate at pH values of 1, 3, and 10. The Si/Al molar ratio for all synthesized samples were 4.72 (± 0.29). The amorphous character of the investigated materials was confirmed by X-ray phase analysis. According to the results of scanning electron microscopy, it was found that the resulting powders have particles with a size of 1-20 μm. It was shown that the conditions of synthesis affected the specific surface area and porosity of the materials under study. By the method of low-temperature adsorption-thermodesorption of nitrogen it was established that silica-aluminas obtained under acidic conditions were microporous materials. For the sample obtained under alkaline conditions (pH = 10), the contribution of macropores is very significant. A decrease in surface area is observed as the pH of the synthesis increases. The Hammett indicator method was used to identify and quantify surface centers of different acidity. All studied silica-aluminas are characterized by the presence of both Brønsted basic (pKax from 7 to 12.8) and acidic (pKax from 0 to 7) centers, and Lewis basic (pKax from -4.4 to 0) with a pronounced maximum at pKax = 1.02. It was found that the synthesis conditions had a significant effect on the concentration of active centers. The values of the Hammett function are practically the same for the 3 studied silica-aluminas and describe the studied samples as materials of medium acidity. The variety of Lewis and Brønsted centers on the surface indicates the amphoteric properties of the materials under study. This gives the samples the properties of polyfunctional sorbents and catalysts.

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