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Showing 6 results for Chitosan
Fluoride Removal from Water By Adsorption using Bagasse, Modified Bagasse and Chitosan
S Jorfi, R Rezaei Kalantary, A Mohseni Bandpi, N Jaafarzadeh Haghighifard, A Esrafili, L Alaei,
Volume 4, Issue 1 (5-2011)
Abstract

Background and Objectives: Fluoride is widely used in industries such as manufacture of semiconductors, power plants, glass production etc and release to the environment via their effluents. The purpose of this sturdy was to compare the efficiency of low price adsorbents in fluoride removal from water.
Materials and Methods: The optimum values of pH, contact time and adsorbent dosage were determined and different concentrations of fluoride were experimented in lab scale conditions for bagasse, modified bagasse and chitosan. Then Langmuir and Freundlich coefficient were determined based on optimum conditions.
Results: The pH value of 7, contact time of 60 min and adsorbent dosage of 2 g/L were determined as optimum conditions for all three adsorbents. The most fluoride removal efficiency of 91% was obtained for modified bagasse in optimum conditions.
Conclusion: Based on data obtained in this study, it can be concluded that adsorption by modified bagasse is an efficient and reliable method for fluoride removal from liquid solutions.


Effect of packaging with Chitosan biodegradable films formulated with Garlic essential oil (Allium sativum L.) on the chemical properties of chicken fillet
E Molaee Aghaee , A Kamkar, A Akhondzadeh Basti , A Khanjari , M.g. Kontominas ,
Volume 8, Issue 3 (12-2015)
Abstract

Background and Objective: Considering the environmental problems raised from current plastic packaging, edible and biodegradable films could be developed and also be effective in controlling the chemical and microbial properties of food especially if their effect be strengthened by adding natural antioxidant and antimicrobial agents like herbal essential oils. This study aimed at assessing the effect of packaging with chitosan film containing garlic essential oil on the chemical changes of chicken fillet during storage at refrigeration temperature.

Materials and Methods: Different levels of garlic essential oil (0, 0.5, 1 and 2%) were used in chitosan film preparation. Through casting method and using glycerol as plasticizer and tween 80 as emulsifier, different films were prepared after homogenization and molding. Chemical tests were conducted in days 0, 2, 4, 7, 10, and 14 on chicken fillets covered with different films and stored at 4 °C. Statistical analysis was performed using SPSS software.

Results: Samples covered with different films showed lower values for pH, total volatile nitrogen (TVN), Thiobarbituric acid-reactive substances (TBARs), and peroxide index (P.V) compared with controls during the study (p ≤ 0.05). Generally, a dose-dependent trend was observed by essential oil addition.

Conclusion: Chicken packaging with chitosan film especially by adding various levels of garlic essential oil could had a preventive effect on major chemical spoilage factors. Considering the relatively similar preventive effect of 1 and 2 % essential oil levels and also economic aspects, optimum dose for essential oil could be 1 % in the film.


Evaluating the performance of modified adsorbent of zero valent iron nanoparticles – Chitosan composite for arsenate removal from aqueous solutions
K Yaghmaeian, N Jaafarzadeh, R Nabizadeh, H Rasoulzadeh, B Akbarpour,
Volume 8, Issue 4 (3-2016)
Abstract

Background and Objective: Arsenic is one of the most toxic pollutants in groundwater and surface water. Arsenic could have lots of adverse impacts on human health. Therefore, access to new technologies is required to achieve the arsenic standard.

Materials and Methods: The present study was conducted at laboratory scale in non-continuous batches. The adsorbent of zero-valent iron nanoparticles -Chitosan was produced through reducing ferric iron by sodium borohydride (NaBH4) in the presence of chitosan as a stabilizer. At first, the effect of various parameters such as contact time (5-120 min), pH (3-10), adsorbent dose (0.3-3.5 g/L) and initial concentration of arsenate (2-10 mg/L) were investigated on process efficiency. Then optimum conditions in terms of contact time, pH, adsorbent dose and initial concentration of arsenate were determined by RSM method. Freundlich and Langmuir isotherm model equilibrium constant, pseudo-first and second order kinetic constants were calculated. The residual arsenate was measured y using ICP-AES.

Results: The optimum values based on RSM for pH, absorbent dose, contact time, and initial concentration of arsenate were 7.16, 3.04 g/L, 91.48 min, and 9.71 mg/L respectively. Langmuir isotherm with R2= 0.9904 for Arsenate was the best graph for the experimental data. According to Langmuir isotherm model, the maximum amount of arsenate adsorption was 135.14mg/g. . The investigation of arsenate adsorption kinetics showed that arsenate adsorption follows the pseudo-second kinetics model.

Conclusion: This research showed that the adsorption process is depended on pH. With increasing pH, the ability of amine groups in chitosan are decreased to protonation, caused to decrease the efficiency of arsenate removal at high pH.


Comparative study of the performance of chitosan and chitosan adsorbents modified with Fe3O4 to eliminate erythromycin from aqueous solutions
M Ghodrat, E Asrari,
Volume 10, Issue 4 (3-2018)
Abstract
Background and Objective: Excessive consumption of antibiotics and the entrance of the potentially hazardous substances to the environment has become one of the environmental concerns. Today, adsorption is one of the efficient and reliable methods for the removal of this class of compounds. The aim of this study was to synthesize chitosan-Fe3O4 and to compare the efficacy of removing erythromycin antibiotics from aqueous humorous media by this adsorbent and chitosan.
Materials and Methods: The structural properties of the synthesized adsorbent were analyzed by TEM, PSA, VSM techniques. Various parameters including pH (1-11), contact time (0-60 min), adsorbent concentration (1-5 g/L), and initial concentrations of erythromycin (5-50 mg/L) was evaluated for the removal efficiency. For data analysis, Excel software was used. The equilibrium constant and the kinetic constants were calculated from the first-order kinetic model using Freundlich and Langmuir isotherms.
Results: The results indicated that increased pH and initial concentration of erythromycin increased the dose of adsorbents and the contact time of removal efficiency. The highest absorption efficiency at pH of 3 for both adsorbents, the contact time 30 min for modified chitosan and 50 min for chitosan, the dose of adsorbent 2 g/L for modified chitosan, and 3 g/L for chitosan and the initial concentration of erythromycin for each of the two adsorbents was 10 mg/L and the erythromycin adsorption by both adsorbents follows the Langmuir isotherm and the pseudo second order kinetics.
Conclusion: According to these results, chitosan modified with Fe3O4 can be used as a more effective adsorbent than chitosan for removal of erythromycin by adsorption method.
 

A comparison on the effects of alginate and chitosan in the synthesis of granular zeolite adsorbents used for arsenic removal
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.
 

Experimental study of adsorption of amoxicillin residue from water samples using nanocomposite based on zirconium metal-organic frameworks and porous polymers
Yadollah Yousefzadeh, Vida Izadkhah, Soheil Sobhanardakani, Bahareh Lorestani, Sedigheh Alavinia,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: Antibiotics as emerging pollutants are harmful to environmental health. Therefore, this study was conducted to investigate the efficiency of Uio-66-NH2@CS-Iso-Gu nanohybrid for the removal of amoxicillin (AMX) from aqueous solutions.
Materials and Methods: In this study, for the first time, guanidine and isocyanate monomers are cross-linked with chitosan. The combination of this polymer with organometallic compounds contributes to its chemical/thermal stability and reusability. Uio-66-NH2@CS-Iso-Gu nanohybrid was characterized using X-ray diffraction (XRD), Scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and BET methods. Also, the effects of pH, initial concentration of AMX, contact time, and temperature were evaluated. Moreover, isotherm, kinetic and thermodynamics studies were performed.
Results: The results of TGA analysis showed that Uio-66-NH2@CS-Iso-Gu nanohybrid was resistant to temperatures up to 400 °C. Also, optimal adsorption of AMX occurred in the first 25 min. The synthesized nanohybrid has a surface area of 101.2 m2/g and a type IV isotherm. Acidic groups were present on the synthesized nanohybrid surface based on the pHpzc = 4.7. Langmuir (for 25 °C and 45 °C) and Freundlich (for 65 °C) isotherm models and pseudo-second-order kinetic models are more appropriate to fit the adsorption data with the experimental data. The maximum adsorption capacity of the synthesized nanohybrid was equal to 56.49, 40.65, and 0.382 mg/g at temperatures of 25°C, 45°C, and 65°C, respectively. Based on the findings, Uio-66-NH2@CS-Iso-Gu nanohybrid could be used for up to five cycles without significantly reducing their performance.
Conclusion: The results showed that Uio-66-NH2@CS-Iso-Gu nanohybrid has a significant efficiency for removing AMX and could be used as an effective adsorbent for the treatment of wastewater containing pharmaceutical residues.
 

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