Evaluation of Diethyl phthalate and Diallyl phthalate biodegradation mechanisms in the treatment of synthetic wastewater

Background and Aims: Over the last few years, Phethalic Acid Esters (PAEs) have attracted a widespread attention due to their widespread production and use. These compounds are not only linked to endocrine disruption and cancer but also considered as emerging and hazardous pollutants. Large amounts of PAEs have been detected in industrial wastewaters. Given the widespread use of biological processes in industrialwastewater treatment, this study aimed to identify biodegradation pathways of PAEs and their potential metabolites.Materials and Methods: Two short-chain esters from phthalic acid esters including diethyl phthalate (DEP) and diallyl phthalate (DAP) were selected in the present study. We used the survey of metabolites in a moving bed biofilm reactor effluent to determine biodegradation pathways of designated esters at hydraulic retention times of 1 to 12 hours. Influent concentration of 100 mg/l was also considered throughout the study.Results: Phthalic acid, mono-methyl phthalate, dimethyl phthalate and catechol were identified as the most noteworthy metabolites in biodegradation of both esters. The degradation pathway of both studied compounds was similar and involves either detachment of ester-chain or removal of methyl group, followed by few decomposition steps resulting in the production of benzene ring. The degradation can proceed further with ring cleavage and it ends with 2-hydroxy muconic semi-aldehyde.Conclusion: The main route for removal of studied compounds was de-esterification followed by demethylation. According to identifies degradation pathways and metabolites produced, biodegradation can be considered as a reliable treatment process for industrial wastewaters containing PAEs.Key words: Biodegradation, Phthalic Acid Esters, Synthetic wastewater

Optimization of phenanthrene contaminated soil washing using Response Surface Methodology

Background and Aims: Soil washing using surfactant is a promising technology for PAHs removal from soil transferring them into liquid phase. The performance of this process is influenced by several factors such as surfactant concentration, washing time, liquid:soil ratio (L/S) and the presence of natural organic matter, which in the present study was totally investigated using the nonionic surfactant Tween 80.Materials and Methods: Surfactant solution with three various concentrations of 500, 2750, 5000 mg/l, at liquid:soil ratios of 10, 20, 30 v/w (ml/g) containing three concentrations of 0, 10, 20 mg/l humic acid (asNOM) was added to phenanthrene contaminated soil samples. The samples were placed on a shaker for timeinterval of 2, 13 and 24 hours, then it was injected to HPLC for phenanthrene concentration analyze. This research was conducted on the basis of central composite design by using response surface method (RSM) in 29 experimental runs.Results: Maximum removal efficiency (77.35%) was achieved under the experimental conditions of 5000 mg/l surfactant concentration, 30 v/w liquid:soil ratio, absence of humic acid and 24 h washing time. Surfactant concentration with impact value of 82.03% was the most effective parameter in phenanthrene removal. L/S was also the other significant factor (P<0.0001), but humic acid and washing time were, statistically,insignificant. The interaction between surfactant concentration and L/S was significant too.Conclusion: Considering the conditions of Iran’s soils containing 3-6 percent organic matter and based on the suggestions of RSM with 95.10% desirability, the optimum conditions for washing high- phenanthrene soil (about 500 mg/kg) with minimum washing time of 2 hours were as 5000 mg/l surfactant concentration, 30 v/w (ml/g) liquid:soil ratio, and 2.1 mg/l humic acid concentration (6.30%).Key words: phenanthrene, soil washing, surfactant Tween 80, optimizatio

An Approach to the Anthropological Theory of the Qur’an and Hadith and Their Roles in Reducing Environmental Degradation

Background: According to the Qur’an, man is the servant and the successor of Allah, the representative of prosperity on earth, and has the responsibility for the universe. This approach will create a constructive human interaction with the environment. Environmental degradation is against the will of Allah. It originates from ignorance, human selfishness, passions, and evil temptations, manifest in greed, arrogance, and extravagance. If humans control these abnormal factors and follow Qur’an teachings, they will enjoy a healthy environment that is a universal right. This paper seeks to study the anthropological theory of the Qur’an and its role in reducing environmental degradation.Methods: Based on the descriptive-analytical design, we explored 70 verses of the Holy Qur’an in which the words samā’, ‘ard, mas’ūl, khalīfah, shaytān, and those are cognate with the Arabic verbs sa-khkha-ra, ha-ra-sa, sa-ra-fa, ki-ba-ra, ha-wā, ‘a-ba-da, and ‘a-ma-ra, as well as the related articles, books, and philological and exegetical sources. We investigated the Qur’an to find the effect of awareness and more attention of human beings to the dimensions of man’s creation to reduce environmental degradation. These issues will be discussed in two parts: 1) the anthropology and the dimensions of human creation in the Qur’an, and 2) the causes of environmental degradation.Results: This study showed that the survival of life and human enjoyment of a healthy environment depends on enough knowledge of oneself, seeking help from Allah, and following the Qur’anic guidelines. These facts effectively control internal and external causes of environmental degradation, including ignorance, egoism, selfishness, and evil temptations. These actions destroy the roots of greed, arrogance, and extravagance in human beings. For this reason, Allah demands humans to develop earth, care for and rescue it from any destruction, avoid extravagance, and observe justice.Conclusion: Meditating in the Qur’an, the man knows his creative dimensions and environmental degradation factors that are incompatible with nature and are rooted in some of the inner and outer dimensions of human personality. Hence, he will consciously enjoy sustainable development and maintaining a healthy environment. This behavior will then reduce anomalies in the environment on his part

Kinetic and equilibrium models for Adsorption of 2,4 DNP compound on chemically modified waste sludge

The contamination of water by organic pollutant viz. 2,4 DNP compound is recognized as most common environmental concern due to their highly toxic nature, worldwide. Adsorption has attracted much attention as a new technique to remove these contaminants from water and wastewater. The purpose of this study was to introduce an inexpensive adsorbent, dried waste sludge, for removal of 2,4 DNP compound. Material & Methods: At first, sludge was dried at temperature 60 °C. Next, CaCl2 was used to improve adsorption capacity. The removal efficiency of 2,4 dinitrophenol were determined by HPLC at wavelength of 360 nm. In addition, the effects of influencing factors including pH, initial pollutant concentration, contact time, and adsorbent dose were examined. The equilibrium binding were described by Langmuir or Freundlich isotherms and kinetic models. Results: The results obtained from adsorption process indicated that was 60 min is the equilibrium time. The optimum pH for adsorption for both adsorbents was found to be 7. The optimum concentration of 2,4-DNP was found to be 10 ppm. The results obtained from the present research showed that the removal of the contaminant using modified sludge sorbent was increased from 40.4% to 77.9% when dosage increased from 0.1 to 1.5 g. Equilibrium adsorption data for 2,4 DNP were fitted by using Langmuir, Freundlich and Freundlich adsorption isotherms model, respectively. Also it has been found that adsorption kinetics can be described according to the Pseudo-second order model. Conclusion: According to results, chemically modified waste sludge showed reasonable adsorption capacity. Therefore, it and can be used as a native alternative to 2,4 DNP compound removal from aqueous environments

Investigation of Photochemical Oxidation Efficiency Process Using H2O2 (UV/ H2O2) in Mineralization of 4-Chlorophenol IN Aqueous Environment

Introduction and purpose: Chlorophenol is known as one of the toxic and dangerous pollutants in industrial wastewaters that’s a essential to it’s removal from industrial wastewaters and ground waters. The aim of this study was to investigate the efficiency of 4-Chlorophenol (4-CP) degradation using Ultraviolet/Hydrogen Peroxide process (UV/H2O2). Methods: The variables of the present study included initial concentration of pollutant, contact time, pH, and H2O2 concentration on 4-Chlorophenol removal on a laboratory scale. The concentration of residual 4-Chlorophenol was determined using UV/Visible at a wavelength of 280nm. In addition, the amount of mineralization in optimal conditions was evaluated using the measurement of total organic carbon (TOC) removal range according to the standard method 5310- B. Synthetic models of the process were also investigated. Results: The optimum removal efficiency of 4-CP by UV/H2O2 process regarding the concentration of hydrogen peroxide was 580 mg/L. pH of 3 and initial 4-CP concentration was obtained as 380 mg/L, and the presence of UV rays with a wavelength of 254 nm during 30m contact was 84.92% . In addition, 84.69% of the TOC was removed under the optimal condition. Moreover ,it was found that the data followed the first-order synthetic models. Conclusion: Considering the growing use of UV radiation in water treatment processes and the considerable efficiency of UV/ H2O2 process in removing 4-CP, this method can be proposed for the elimination of 4-CP after performing cost-benefit analyses. It can be concluded that with regard to purification goals and standards for wastewater treatment, UV/ H2O2 process can be used as a pre or final treatment

Effectiveness of Rice Husk Ash in Removal of Phenolic Compounds from Aqueous Solutions, Equilibrium and Kinetics Studies

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol compounds even at low concentration can cause toxicity, health and significant taste and odor problem in drinking waters. This research focuses on understanding the sorption process and developing a cost-effective technology for the treatment of water contaminated with phenolic compounds, which are discharged into the aquatic environment from a variety of sources. In order to remove phenolic compounds from water, a new natural sorbent, rice husk ash, was developed.Materials and Methods: Removal of phenol, 2-chlorophenol and 4-chlorophenol were characterized by spectrophotometric technique at wavelengths of 269.5, 274 and 280 nm, respectively, under batch equilibrium conditions and via changing the parameters of contact time, initial pH, and initial concentration of adsorbates and dosages of sorbent. Finally, the results were analyzed by the kinetic and isotherm models.Results: in this study, the equilibrium time was found to be 240 min for full equilibration of adsorbates. Removal percent of 2-chlorophenol was lower than two others. The maximum removal of phenol, 2-CP and 4-CP was observed at an initial pH of 5. The percentage removal of these phenolic compounds increased with increasing adsorbent dose and decreasing initial concentration. In kinetics studies, correlation coefficient and ARE factor showed that the sorption of phenol (R2=0.9999), 2-chlorophenol (R2=0.9992) and 4-chlorophenol (R2=1) fitted by pseudo second order model. Isotherm studies also revealed that, Langmuirmodel for phenol (R2=0.9499), Freundlich model for 2-chlorophenol (R2=0.9659) and 4-chlorophenol (R2=0.9542) were the best choices to describe the sorption behaviors.Conclusion: Sorption process is highly dependent on the pH and it affects adsorbent surface characteristics, the degree of ionization and removal efficiency. At high pH hydroxide ions (OH-) compete for adsorption sites with phenol molecules. The sorption was done rapidly and a plateau  was reached indicating the sorption sites occuupied till  they were saturated. Since the increasing sorbent dose would improve sorption site, its increasing enhances phenolic compounds removal. st1":*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;

Synthesis and Characterize of Zeolite- Zero Valent Iron/ Silver Nanocomposite (Z-Fe0 /Ag) for Removal Fluoride in Aqueous Solutions (Study of Isotherms, Kinetics and Thermodynamics)

Background: Fluoride is a pollutant that entered to the environment through Glass, Fertilizer and Semiconductor Material industries and cause problems such as Alzheimer's and brain injuries. Adsorption with using inexpensive materials like zeolite is the best options to remove this pollutant. The main problem of absorption method is its low speed. So the aim of present study is investigated the effect of Fe0/Ag nanoparticles as catalyst in performance of zeolite for removal of fluoride. Methods: In this study were used reduction method for converting Fe2+ to Fe0 and co-precipitation method for coating of Fe0 on Zeolite. For depositing silver on nano zero valent iron the rapid mixing along with the high temperature were used. Absorbent characteristics were analyzed with using SEM, TEM and XRD techniques. Then effect of pH, contact time, stirring speed, temperature, amount of adsorbent and Fluoride concentration were evaluated and optimized. Results: pH=3, 60 min contact time, 200 rpm stirring speed and adsorbent concentration equal to 10g/l were obtained as the optimum conditions for Fluoride removal. Investigating the isotherms and kinetics relationships showed that the experimental data correlate to the Langmuir adsorption isotherm model (R2>0.991) and pseudo-second order kinetics (R2>0.933). The reaction thermodynamic study also expressed that process is endothermic and non-spontaneous Conclusion: According on the obtained results can be stated This Absorbent has appropriate efficiency in fluoride removal, But the catalytic properties of zero valent iron and silver was rejected in relation to removal this contaminants