Showing 9 results for Zeolite
B. Mortazavi, L. Rasuli, H. Kazemian,
Volume 3, Issue 1 (4-2010)
Abstract
Backgrounds and Objectives: Hexavalent Chromium is an important contaminant in surface and ground waters and removal from contaminated water and waste water has received interest in recent years. Modified Zeolite with cationic surfactant can remove Cr(VI) from contaminant water. The aim of this research is investigation of Cr (VI) removal from aqueous solutions and its effective parameters by using Modified Zeolite with cationic surfactant.
Materials and Methods:In this research the efficiency Of Cr(VI) removal and impact of the important parameters including adsorbent dose, pH and contact time in the batch system was studied.
Results:The results of this research showed that SMZ can remove more than 90 & Cr(VI) in the concentration 0.1-1.25 mg/l with optimum dose 0.3 gr and pH=6 120 minute in contact time.
Conclusion: Modified natural zeolite have significant potential inCr(VI) removal fromcontaminated water.Maximumpercent removal ofCr(VI)was in the pH=6 and 120minute contact time.Adsorption data in the equilibrium was fitted with Langmuir isotherm. Separation factor was between 0 and 1 that indicates the favorable condition for Cr(VI) adsorption on the SMZ.
M.t Samadi, M.h Saghi, K. Ghadiri, M. Hadi, M. Beikmohammadi,
Volume 3, Issue 1 (4-2010)
Abstract
Backgrounds and Objectives:Phosphate discharges from domestic and industrial waste water to water bodies. High concentrations of phosphate in water stimulate the eutrophication phenomenon that causes taste and odor in water, losing dissolved oxygen and aquatic life in rivers or surface waters. Aim of this study is survey of phosphate adsorption on simple nano zeolite Y and nano zeolite Y that was modified with a cationic surfactant (HDTMA-Br).
Materials and Methods:In This study we used simple nano zeolite Y and nano zeolite Y in form of Surfactant Modified Zeolites (SMZs) using batch tests to adsorption of Phosphate fromAqueous Solutions. The adsorbants were contacted with different initial phosphor concentrations (5, 10 and 15 mg/l), pH (4, 7, 12), contact time (30, 60, 90, 120, 150 and 180 minutes) and weight of adsorbant (0.2, 0.4, 0.6, 0.8 and 1g). the extracted solution was determined for Phosphate concentration by the ammonium molybdate and tin chloride method with spectrophotometric detection at 680 nm. Results:Results of this study show that, with increase in contact time, decrease in pH, increase in zeolites concentration and decrease in initial phosphate concentration, the removal efficiency increased. And the Both isotherm of Langmuir and Freundlich models (r2 > 0.997 and r2 > 0.996 respectively) were agreement with adsorption equilibrium of phosphate. Reduced Chi-Sqr For Langmuir and Freundlich models were (0.00079) and (0.0011) respectively. Pseudo first-order kinetic models fits well with experimental data (r2>0.963).
Conclusion: From this survey, it is concluded that performance of modified nano zeolite Y for adsorption of phosphate in same conditions is better than non-modified zeolite Y. In general the modified nano zeolite Y presented a good profile for removal of phosphate. Therefore SMZs is a suitable candidate for removal of Phosphate molecules from contaminated solutions in contaminated waters.
Ruhollah Rostami, Ahmad Jonidi Jafari, Roshanak Rezaee Kalantari, Mitra Gholami,
Volume 5, Issue 1 (4-2012)
Abstract
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MicrosoftInternetExplorer4 Background and Objectives:Benzene,
toluene and Xylenes (BTX) are organic pollutants, which are mainly associated
with oil and its derivatives. BTX is environmental contaminants and considered
harmful to human health. Application of surface absorbents such as zeolite is
one of several methods for the removal of these compounds. In this study,
BTX compounds'
removal efficiencies were
investigated and compared by using
clinoptilolite
type zeolite
and zeolite
with copper
oxide nanoparticles.
Materials
and Methods: In this study, the modified zeolite by
hydrochloric acid in the grain size 1-2 mm and modified zeolite with nano
particle of copper oxide were used. Artificially- Contaminated Air
flow was used
continuously .To determine
BTX concentrations,
samplings were done by charcoal tube in
current input and output. The
concentrations of contaminants were determined by gas chromatography with FID
detector.
Results: Removal efficiency of benzene,
toluene, p-xylene, m-xylene and o-xylene by clinoptilolite were 78.3%, 62.1%,
32.2% 32.15% and 18.8%, respectively. For the clinoptilolite
containing copper oxide nano particles efficiency were 25.42%, 35.65%, 36.33%,
33.24% and 29.39%, respectively. Average removal efficiency of BTX compounds
observed when the zeolite without nanoparticles used (43.31%) was more than
zeolite with nanoparticles (32%). The results showed that the concentration of
CO2 in the outlet air of the zeolite-containing nanoparticle (550
ppm) was more than the zeolite without nanoparticle (525 ppm).
Conclusion: Results showed that adding nanoparticles to the
zeolite, although the removal efficiency of benzene and toluene
can be reduced.
The results showed that adding
nanoparticles to the zeolite, although can be reduced removal efficiency of
benzene and toluene, which may be due to occupying or blocking of the pollution
absorption sites by the nanoparticles on the zeolite, but It cause promote more
catalytic effect of zeolite in the decomposition process of contaminants by
breaking the molecules of pollutants and their further degradation progress is
done for conversion to carbon dioxide
Omol Banin Naeej, Anoushiravan Mohseni Bandpi, Ahmad Jonidi Jafari, Ali Esrafili, Roshanak Rezaei Kalantary,
Volume 5, Issue 3 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Nitrate is one of the most groundwater pollutants in world.
Reduction of nitrate to nitrite by microorganisms cause serious health hazards.
Nitrate can be eliminated using either adsorbtion or reduction. In this study,
we investigated the adsorption of nitate on zeolite and the feasibility of
removal improvement using supported zero
valent nano iron on zeolite via the reduction process.
Materials and Methods: The study was done in two phases investigation the
zeolite and modified zeolite with zero valent nano iron in nitrate removal from
water. First, we determined the optimum pH and time then the effect of
adsorbent and nitrate concentration was investigated in one factor at the time.
The adsorption isotherm was calculated according to the optimum condition. The
physical characteristics of adsorbents were determined using SEM and TEM.
Results: The morphology investigation of adsorbent showed that the
particle size of supported zero valent nano iron on zeolite was approximately
30-50 nm in diameter. The best conditions were pH 5, contact time of 120 min
and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for
supported zero valent nano iron on
zeolite. The isotherm equations revealed that nitrate adsorption follows
Langmiur in both cases.
Conclusion: The supported zero
valent nano iron on zeolite could be considered as a high potential adsorbent
for nitrate because it has several adsorbent sites, and Fe
0 as a
function for nitrate reduction.
Afshin Maleki, Amir Hossein Mahvi, Reza Rezaee, Behrouz Davari,
Volume 5, Issue 4 (2-2013)
Abstract
Background and Objectives: Dyes are an important class of pollutants, which can even be identified by naked eye. Disposal of dyes in precious water resources have been prohibited, however, various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. Therefore, natural zeolite (clinoptilolite) and acid modified zeolite were used as a low-cost adsorbent to evaluate their ability to remove color from aqueous solution using a batch adsorption experiments.
Materials and Methods: Modification of zeolite surface was carried out with two acids sulfuric acid and phosphoric acid, to improve the removal efficiency of reactive blue 19. We studied the influence of acid concentration, contact time, solution pH, initial dye concentration, and adsorbent dosage on the removal efficiency.
Results: The parameters of Langmuir and Freundlich adsorption isotherms have been determined using the adsorption data. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. It was also found that adsorption of dye by zeolite followed pseudo first-order kinetics. The adsorption results indicated that natural zeolite has a limited adsorption capacity for reactive dye but can be distinctly improved by modifying its surfaces with acid. Experimental results also showed that sulfuric acid has better performance than phosphoric acid in the modification of zeolite for dye adsorption.
Conclusion: We achieved the best results in terms of removal efficiency (41-72%) for the zeolite modified with Si/Al ratio of 7.5 after 3 h of contact.
K. Naddafi, M. Gholami,
Volume 7, Issue 3 (5-2014)
Abstract
Background & objective: Synthetic dyes are extensively used in various industries such as textile, leather tanning, plastic, pulp and paper. Since dyes are toxic and even carcinogenic, discharging dye-containing wastewater into the environment poses serious environmental and health problems. Therefore, the purpose of this paper was to evaluate the removal of Reactive Red 120 from aqueous solutions using surface modified natural zeolite. Materials &Methods: The Semnan zeolite was sieved using standard sieves in size of 0.2 - 0.3 mm and then was modified by cationic surfactant. Batch adsorption studies carried out to study various parameters included contact time, initial concentration of Reactive Red 120, pH, and adsorbent dosage. The concentration of dye was measured using a UV-vis Spectrophotometer at the wavelength of 537 nm. Freundlich and Langmuir isotherms and Pseudo-first order and pseudo-second order kinetics were used to analyze the isotherm and kinetic data respectively. Results: The adsorption studies indicated that increasing of the contact time, initial concentration of Reactive Red 120, decreasing pH and adsorbent dosage leads to increasing dye adsorption. Equilibration of Reactive Red 120 adsorption was reached at lapse of 90 min. Moreover, it was found that Langmuir isotherm (R2=0.9814) and pseudo second-order kinetic (R2=0.9814) are well fitted with our data. Conclusion: The results of the study show that Iranian modified zeolite can be used effectively for removal of Reactive Red 120 in comparison with other parts of the world. Considering the cost, availability and ease of modification, it can be used to remove dye in industrial wastewater.
A Shahbazi,
Volume 8, Issue 3 (12-2015)
Abstract
Background and Objectives: Rapid growing of Triton X-100 application in industries results in its appearance in effluents and threaten the aqueous ecosystems. Triton X-100 is not biodegradable and can accumulate in food chain.
Materials and Methods: In this study, sorption capacity of six synthesized zeolites with different regular porous structure was studied for triton X-100 (TX-100) surfactant and the results were compared with Clinoptilolite natural zeolite of Damavand region.
Results: Within all zeolite studied, Beta(200) showed the highest sorption capacity (about 575 mg/g), which is due to its regular pore structure with large pore diameter, channel intersections, high SiO2/Al2O3 ratio and high surface area. Langmuir monolayer isotherm and pseudo-second-order kinetic equation could provide well-fitted to the experimental data in simulating adsorption behavior of TX-100 over Beta(200) zeolite.
Conclusion: The adsorption feature was internal sorption and the intraparticle diffusion might be a rate-limiting control for Beta(200) zeolite. Results of experiments demonstrated that the hydrophobic zeolites with large pore diameter such as Beta(200) could be effective sorbents for industrial wastewater treatment features.
H Irvani, H Shojaee - Farah Abady, M Shahryari, M Nakhaei Pour,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Styrene monomer is a volatile organic compound that is used in the various industries. Due to the hazardous effects of this chemical substance on the environment and humans, control and elimination of this vapour is necessary. Therefore, the aim of this study was to remove the styrene vapors from air flow using photocatalytic activity of zinc oxide immobilized on ZSM-5 zeolite.
Materials and Methods: In this experimental study, the fabricated catalysts were characterized using analysis of BET, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dynamic Concentrator System were used to generate styrene vapors at a certain concentration and flow, and then removal efficiency of the styrene vapors was investigated using UV/ZnO and UV/ZSM-5/ZnO.
Results: The results of XRD analysis and SEM images showed that produced zinc oxide had nano dimensions. In addition, these nanoparticles was successfully stabilized on ZSM-5 zeolite. The results of the photocatalytic removal showed that ZnO and ZSM-5/ZnO catalysts at the concentrations of 50 ppm eliminated the styrene vapor 14% and 37%, respectively.
Conclusion: Findings of this study showed that stabilization of zinc oxide nanoparticles on ZSM-5 zeolite had an ssynergistic effect on the photocatalytic degradation of styrene. According to this finding, the use of adsorption-photocatalyst hybrid systems can be an appropriate technique to remove styrene vapors and other similar pollutants.
Maryam Tahmasebpoor, Leila Sanaei, Masoomeh Chaharkam,
Volume 16, Issue 3 (12-2023)
Abstract
Background and Objective: Zeolites are among the widely used adsorbents for the removal of arsenic-toxic pollutants. The objective of this study is to prepare granulated zeolite adsorbents using chitosan (CS/Fe-Clin) and alginate (Alg/Fe-Clin) and compare them in terms of physical appearance and arsenic adsorption efficiency.
Materials and Methods: Granular adsorbents were prepared via the ionotropic gelation method. The effects of the type and concentration of the cross-linking solution and the initial ratio of materials in granules formation, as well as the effect of initial arsenic concentration, and the amount of adsorbent used on the adsorption efficiency, were investigated. SEM, XRD, FTIR, and AAS analyses were used to confirm the results. Equilibrium data were matched with Freundlich and Langmuir isotherms.
Results: A weight percentage of 2 % iron chloride (III) and an initial ratio of 1:4 of alginate: nanocomposite for Alg/Fe-Clin and a weight percentage of 2 % (1 % sodium hydroxide + 1 % sodium tripolyphosphate) and an initial ratio of 1:3 of chitosan: nanocomposite for CS/Fe-Clin were chosen as the optimal values. Maximum adsorption efficiency of Alg/Fe-Clin and CS/Fe-Clin adsorbents was determined 88.1 and 92.9 % at dosages of 0.6 and 1 g/L and at initial concentrations of 200 and 300 µg/L, respectively. The qmax values for Alg/Fe-Clin and CS/Fe-Clin adsorbents were 11.11 and 10 mg/g, respectively. Results better fitted with Freundlich isotherm.
Conclusion: Due to the proper adsorption capacity, both synthesized adsorbents showed the ability to effectively remove arsenic; whoever, alginate binder was more efficient.
