24 research outputs found
Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash
Background: Phenol is a prevalent pollutant found in many industrial wastewaters, and it is paid
singular attention because of its special features like high toxicity, carcinogenic properties, and vital
gathering ability that affects the health of humans and the environment. One of the most important
technologies for the removal of phenol is the use of adsorbents. The current study investigated the
removal of phenol from synthetic aqueous solutions using Citrullus colocynthis seed ash.
Methods: This study is experimental and was conducted on a pilot scale. The efficiency of phenol
removal by C. colocynthis seed ash was evaluated in a batch system, and different parameters such as
initial concentration of phenol (10, 20, 50, and 80 mg/L), contact time (2, 5, 10, and 30 minutes), pH
(2-12), adsorbent dose (0.5, 1, 3, 5, and 10 g/L), and temperature were studied. Excel software was used
for data analysis. The adsorption process was modeled with Freundlich and Langmuir isotherms at
controlled temperatures.
Results: The results showed that the highest removal rate of phenol was obtained at a pH of 2 (83.4%),
initial phenol concentration of 20 ppm (66.4%), adsorbent dose of 5 g/L (86.8%), and contact time of 10
minutes. The evaluation of correlation coefficients showed that the phenol adsorbed by C. colocynthis
seed ash was in greater accordance with the Freundlich model than the Langmuir model.
Conclusion: In general, the results of this study revealed that C. colocynthis seed ash has suitable
potential for use in removing phenol from aqueous solutions on operation and practical scales due to
its low cost and easy access.
Keywords: Phenol, Adsorption, Citrullus colocynthi
Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment
Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs) and Halo Acetic Acids (HAAs) in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA) in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm) and H2O2 (20, 40, 60, and 80 ppm) initial concentrations, Iron (II), sulfate heptahydrate dosage (4, 8, 12, and 16 ppm), pH (2, 3, 4 and 5), Oxidation time (5, 10, 15 and 30 min), and Sunlight levels (322±13 kWm-2). To accelerate the process of HA removal, the Solar Photo-Fenton (SPF) process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC), with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC) concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm), the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments
Prevalence of Sick Building Syndrome (SBS) among Students and Teachers of Guidance Schools in Babol, Winter 2018
Background: It is important to determine the prevalence of Sick Building Syndrome (SBS) symptoms in school students and teachers, which is relevant to the physical environment of the building. The aim of this study was to determine the prevalence of sick building syndrome in students and teachers of guidance schools in Babol.
Methods: This descriptive and analytical cross-sectional study was carried out in 15 guidance schools in Babol in the winter of 2018, among 150 students and 95 teachers. The MM040EA (Miljomedicine040) questionnaire was used to collect data and was completed by interview. Data were analyzed using Chi-square test.
Results: Among the 12 symptoms of SBS, 50.7% of students had fatigue, and 44.7% had headaches. There was a significant correlation between heavy headedness (p = 0.42) and headache (p = 0.029) with students’ gender. There was a significant correlation between the teachers’ gender with the redness or dryness of facial skin (p = 0.015), redness or itching of hands (p = 0.009) and also fatigue (p = 0.003). There was a significant correlation between the symptoms of the SBS with very high temperature in the students (p = 0.050), and with the noises (p = 0.40) in the teachers.
Conclusion: The present study showed that more than half of the students and teachers had symptoms of SBS. Since the symptoms of SBS are associated with some physical conditions of the classroom and school environment, the health condition of the schools should be annually checked for all aspects
The data of Escherichia coli strains genes in different types of wastewater
From April 2016 to March 2017, a number of 99 isolates of Escherichia coli were collected from three types of wastewater including urban wastewater (33 isolates), livestock slaughterhouse wastewater (33 isolates) and poultry slaughterhouse wastewater (33 isolate). The specimens were cultured on microbiological media. The bacterial identification was performed by morphological and biochemical tests. Polymerase chain reaction (PCR) method was carried out to detect 2 virulence genes (traT, and fimH) and 4 antibiotic resistance genes (bla TEM, CTX, SHV, and tetA). The data showed that the prevalence rate of traT, fimH,blaCTX, blaTEM,blaSHV, tetA genes were 89.9%, 91.9%, 79.8%, 40.4%, 6.1%, and 91.9%, respectively. Keywords: Escherichia coli, Wastewater, Virulence genes, Resistance genes, Antibiotic resistanc
Data on efficient removal of acid orange 7 by zeolitic imidazolate framework-8
A water stable and hybrid nonporous adsorbent, cubic zeolitic imidazolate framework-8 (ZIF-8), was synthesized for Acid orange 7 (AO7) removal from aqueous solutions in batch mode. Central composite design was utilized to explore the individual and interaction effects of pH, AO7 concentration, ZIF-8 dosage and contact time on dye adsorption. A second order polynomial equation (R2 = 0.9852, LOF = 0.1419) developed for prediction of the AO7 removal. Sorption model revealed that the adsorbent dosage and the dye concentration are major factors that controlled the AO7 removal efficiency. AO7 removal increased from 55 to 80% by increasing ZIF-8 dosage from 0.2 to 1 g/L. The dye removal, on the other hand, decreased from 84 to 70% with increasing AO7 concentration from 10 to 100 mg/L and increased from 60% to 80% by decreasing pH from 12 to 4. The dye removal followed the pseudo second order kinetic and the Langmuir isotherm model. The maximum monolayer adsorption capacity of 80.47 mg dye/g of ZIF-8 was obtained according to the Langmuir model. Keywords: Adsorption, Acid orange 7, Cubic ZIF-8, Central composite desig
The Study of Citrullus colocynthis Shell Ash Efficiency in Phenol Removal from Synthetic Aqueous Solution
Introduction and purpose: Phenol is one of the common pollutants found in many industrial effluents , which affects the environment and human health due to its special features like high toxicity and carcinogenic properties. The use of adsorbents is one of the most effective strategies for the removal of phenol. In this study, we investigated the efficiency of Citrullus colocynthis shell ash as a natural adsorbent in phenol removal from aqueous solutions. Methods: This was an experimental study, where the effect of different variables such as the initial phenol concentrations (i.e., 10, 20, 50, 80, and 100 ppm), contact time (i.e., 2, 5, 10, and 30 min), adsorbent dose (i.e., 0.5, 1, 3, 5, 7, and 10 g/L) and pH (2-12) were studied. Then, the adsorption process was described with Freundlich and Langmuir isotherms at controlled temperatures. Excel software was used for data analysis. Results: The results revealed that the highest removal rate of phenol was obtained at pH of 2 (79.8%), primary phenol concentration of 20 ppm (66.4%), adsorbent dose of 5 g/l (86.8%), and contact time of 10 minutes. Also, the correlation coefficients of isotherms (Freundlich and Langmuir) showed that phenol adsorption by Citrullus colocynthis shell ash had more accordance with the Freundlich model than the Langmuir model. Conclusion: We found that Citrullus colocynthis shell ash can be used as a lowcost and accessible adsorbent for phenol removal from aqueous solutions
Removal of Reactive Black 5 dye from Aqueous Solutions by Adsorption onto Activated Carbon of Grape Seed
Background and purpose: The control of environmental pollution especially the pollution of water resources is one of the main challenges of researchers throughout the world. So, this study aimed to investigate the efficiency of reactive black 5 dye removal from aqueous solutions by adsorption onto activated carbon of grape seed.
Materials and Methods: At first, the grape seed adsorbents were prepared in three forms of raw, treated by concentrated phosphoric acid, and calcined at 400, 600, and 800 °C. Then, the efficiency of adsorbents to the removal of the Black 5 dye was studied in the concentrations of 100 to 700 mg/Lat pH 2- 10 and 1- 10 g/L of adsorbent during 120 min. The change of concentration was studied via the spectrophotometry procedure at the wavelength of 597 nm. Finally, the Langmuir and Freundlich adsorption isotherm was determined.
Results: The results showed that the dye removal efficiency decreased by increasing pH, and increased by raising the contact time and the amount of adsorbent. So, in this process, the highest percentage of Black 5 dye removal (83.08%) was obtained at pH 2 and t 120 min using the raw adsorbent, 200 mg/L initial concentration of dye, and 10 g/L of carbon. The process considerably followed the Langmuir adsorption isotherm (R2 0.999).
Conclusion: The grape seed was found to have the highest level of efficiency in dye removal, and according to the availability of adsorbent and its low price, this method could be used as an applicable procedure for the removal of Black 5 dye from aqueous solutions
Identifying and Determining Dispersion Boundary Bio-aerosols of Bacterial and Fungal Pathogens from Municipal Waste Collection Containers
Background & Aims of the Study: Identifying and determining the dispersion boundary bio-aerosols of bacterial and fungal pathogens for locating containers of municipal waste in accurate management to prevent from health damage and enhance society health is essential. The aim of this research is to identify and assess the radius of bacterial and fungal bio-aerosol emissions from municipal waste collection containers.
Materials and methods: This was a cross- sectional study in Gonabad city in which air sample prepared from around the containers from July to October 2015. Sampling was carried out by active Zefon A6 Impactor samplers at a distance of 1.5 m from surface of earth and in several horizontal distances up to 2 m from containers. Totally, 360 samples were gathered and the bacteria and fungi were identified by microbiology tests. Also, temperature, humidity and wind speed was measured.
Results: Aspergillus, yeast and Alternaria were the most dominant species of fungi in around of containers. Among bacteria, gram-positive bacilli and Staphylococcus epidermidis were dominant. Most of bio-aerosols in a distance of 25 cm from the containers (228.00±167.12 CFU/m3) and the lowest were observed at a distance of 2 m of the containers (223.86±204.72 CFU/m3).
Conclusion: The findings indicated that municipal waste collection containers released the hazardous biological agents as Aspergillus and Staphylococcus aureus that are very pathogenic for human in environment. So the position of the garbage containers for decline the environment health effect, it should not be less than 2 m from human exposure
Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash
Background: Phenol is a prevalent pollutant found in many industrial wastewaters, and it is paid
singular attention because of its special features like high toxicity, carcinogenic properties, and vital
gathering ability that affects the health of humans and the environment. One of the most important
technologies for the removal of phenol is the use of adsorbents. The current study investigated the
removal of phenol from synthetic aqueous solutions using Citrullus colocynthis seed ash.
Methods: This study is experimental and was conducted on a pilot scale. The efficiency of phenol
removal by C. colocynthis seed ash was evaluated in a batch system, and different parameters such as
initial concentration of phenol (10, 20, 50, and 80 mg/L), contact time (2, 5, 10, and 30 minutes), pH
(2-12), adsorbent dose (0.5, 1, 3, 5, and 10 g/L), and temperature were studied. Excel software was used
for data analysis. The adsorption process was modeled with Freundlich and Langmuir isotherms at
controlled temperatures.
Results: The results showed that the highest removal rate of phenol was obtained at a pH of 2 (83.4%),
initial phenol concentration of 20 ppm (66.4%), adsorbent dose of 5 g/L (86.8%), and contact time of 10
minutes. The evaluation of correlation coefficients showed that the phenol adsorbed by C. colocynthis
seed ash was in greater accordance with the Freundlich model than the Langmuir model.
Conclusion: In general, the results of this study revealed that C. colocynthis seed ash has suitable
potential for use in removing phenol from aqueous solutions on operation and practical scales due to
its low cost and easy acces
Phenol Removal from Aqueous Solutions by Adsorption on Activated Carbon of Miswak’s Root Treated with KMnO4
Background and Purpose: Phenol and derivatives are common pollutants of drinking water
which are blamed for crucial adverse effects such as poisoning, cancer, and malformation. In
this study, an activated carbon of Miswak’s root (MR) was used for the removal of phenol from
aqueous solutions as a low-cost and high surface adsorbent.
Materials and Methods: Adsorption experiments were then conducted in a batch reactor with
activated carbon prepared from MR and treated with KMnO4 to study the effects of contact time
(0-180 minutes), pH (3-13), initial phenol concentration (100-1000 mg/L), and adsorbent
dosage (0.1-1 g/L) at lab temperature 30 ± 1° C on sorption efficiency. KMnO4 treatment
influenced the physicochemical properties of the carbon and improved its adsorption rate.
Results: The results showed that the equilibrium time of adsorption was 120 minutes maximum
adsorption capacity (94.76% phenol removed) of the MR carbon was 142.15 mg/g at pH 5, the
initial concentration of 100 mg/L, 30° C and 180 minutes contact time. The optimum type of
MR adsorbent was produced in 800° C. The equilibrium data were analyzed by the Langmuir
and Freundlich isotherms and fitted well with the Freundlich model (R2 = 0.9821) better than
Langmuir (R2 = 0.7551) model.
Conclusion: The results revealed that the carbon of MR modified with KMnO4 had a
satisfactory quality in phenol adsorption and can well be used as a novel, inexpensive, effective,
and efficient adsorbent for the removal of phenol from the aquatic environment