Avicenna Journal of Environmental Health Engineering

Research Article

20/6/2015

Adsorption of Cu2+ Ions From Aqueous Solutions Using Oxidized Multi-Walled Carbon Nanotubes

Soheil Sobhanardakani, Raziyeh Zandipak, Mehrdad Cheraghi

Copper ion (Cu²⁺) is one of the heavy metal ions that cause environmental pollution specifically in water. Copper ion cations are not biodegradable and tend to cumulate in living organisms. Consequently, the removal of Cu²⁺ in environmental samples plays an important role in environmental pollution monitoring. The purpose of the present work was to prepare oxidized Multi-Walled Carbon Nano Tubes (MWCNTs) for removal of Cu²⁺ ions from aqueous solutions. This study was conducted under laboratory conditions. Multi-Walled Carbon Nano Tubes were oxidized and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and the Brunauer, Emmett, and Teller (BET) methods. The effects of various factors, such as solution pH (3 - 9), adsorbent dose (0.006 - 0.06 g) and contact time (10 - 120 minutes) were investigated. Results showed that the suitable pH for Cu²⁺ ions removal was about 6.0, and the optimal dose was 0.03 g. Isotherm studies indicated that the Langmuir model fits the experimental data better than the Freundlich model. Maximum Cu²⁺ adsorption capacity was calculated as 200 mg g-1. The kinetics of the adsorption process was tested for the pseudo-first-order and pseudo-second-order models. The comparison among the models showed that the pseudo-second order model best described the adsorption kinetics. The results showed that oxidized MWCNTs can be used as a low cost adsorbent for the removal of Cu²⁺ ions from aqueous solutions.

Research Article

20/6/2015

Evaluation of a Landfill Site Using AHP and TOPSIS Models: A Case Study of Ardakan Landfill, Iran

Saba Zakerian, Mehdi Mokhtari, Sayed Ali Alhosseini Almodaresi

Evaluating municipal landfills is vital due to the importance of health and environmental issues and the possibility of contravening environmental and engineering criteria and principles. The present research was conducted to evaluate Ardakans’ municipal landfills using the analytical hierarchy process (AHP) and the technique for order of Preference by similarity to ideal solution (TOPSIS) models. The data were collected through library studies and organizational references, observations, and interviews with experts and authorities, especially those at Ardakan Municipality. Then, the evaluation criteria and sub-criteria and their options for running the TOPSIS model were chosen, and the AHP model and expert analysis as well as maps created in the geographic information systems (GIS) environment were used to weight them. Finally, the weights were inserted in the TOPSIS 2010, and the final ranking of the options and closeness coefficient were presented. The findings showed that from the options available for municipal landfill evaluation in Ardakan, appropriate and almost appropriate had the highest ranks with coefficients of 0.75 and 0.67, respectively. The results showed that the Ardakan municipal landfill is almost appropriate from the TOPSIS perspective and appropriate to very appropriate according to the evaluation criteria available.

Editorial

20/6/2015

Stabilization of Excess Sludge From Poultry Slaughterhouse Wastewater Treatment Plant by the Fenton Process

Zeinab Masoumi, Reza Shokoohi, Zeinab Atashzaban, Nahid Ghobadi, Ali Reza Rahmani

For stabilization of excess sludge in activated sludge process, the Fenton process was applied as a safe technique and its effectiveness was experimentally examined. In order to carry out experiments, a batch reactor with the effective volume of 0.5 L was used. Effect of hydraulic retention time, pH, H₂O_2, and Fe concentrations on sludge stabilization were investigated. Before and after the process, the content of total solids (TS), volatile solid (VS), chemical oxygen demand (COD), and color were measured. The study showed that, the best efficiency was obtained when iron concentration was 60 mg/L, duration of the process was 150 minutes, pH = 3, and H₂O₂ concentration was 4000 mg/L. The Fenton process can reduce the values of TS, VS, COD, and color to 50%, 61%, 53% and 61%, respectively. By analogy to conventional methods, the Fenton process is an effective method that can be suggested to stabilize excess sludge.

Research Article

30/6/2015

A Comparison Study on the Removal of Phenol From Aqueous Solution Using Organomodified Bentonite and Commercial Activated Carbon

Mostafa Leili, Javad Faradmal, Farzaneh Kosravian, Mahdieh Heydari

The potential of bentonite modified with cationic surfactant (CTAB-Bent) and commercial Activated Carbon (AC) for the removal of phenol removal was assessed. Batch kinetics and isotherm studies were carried out to evaluate the effects of contact time (t), phenol initial concentration (C₀), adsorbent dose (C_ads), and pH of the solutions. Kinetics and isotherm of the adsorption were also determined using the most frequent models. The results of the study showed that increasing C₀ could result in the increase of adsorption capacity of both types of adsorbents. The optimum pHs for CTAB-Bent and AC were determined as 10 and 8, respectively. The equilibrium data of the phenol adsorption from the aqueous solutions was well fitted by the Langmuir isotherm models. The kinetics study revealed that pseudo-second-order kinetics gives better description of adsorption process. The adsorption capacities, as deduced from the adsorption isotherm were 22.68 and 112.36 mg/g for CTAB-Bent and activated carbon, respectively. However, considering the market price of these adsorbents, low-cost modified bentonite can be a promising adsorption technology and an alternative adsorbent to commercial activated carbon in the future.

Research Article

29/6/2015

Groundwater Quality Assessment Based on Geographical Information System and Groundwater Quality Index

Zahra Derakhshan, Seyed Ali Almodaresi, Mohammad Faramarzian, Ali Toolabi

Iran is located in an arid and semi-arid part of the world. Accordingly, the management of the water resources in the country is a priority. In this regard, determining the quality and pollution of surface water and groundwater is very important, especially in areas where groundwater resources are used for drinking. Groundwater quality index (GQI) checks the components of the available water with various quality levels. To assess the quality of drinking groundwater of Yazd-Ardakan plain according to GQI in geographical information system (GIS) environment, the electrical conductivity, sodium, calcium, magnesium, chlorine, pH, sodium adsorption ratio, bicarbonate, sulfate, potassium, water hardness, and all substances dissolved in the waters of 80 wells were determined. The samples were obtained from Yazd Regional Water Organization from 2005 to 2014. Using this data, the map components were plotted by Kriging geostatistical method. Then, the map of GQI was prepared after normalizing each map component, switching to a rating map, and extracting the weight of each component from the rating map. Based on the GQI index map, the index point which was 87 in 2005 has increased to 81 in 2014. These maps show a decline in groundwater quality from west to the east region. This decline in groundwater quality is due to the existence of Neogene Organizations in the east and geomorphologic unit of the bare epandage pediment in the west. The map removal and single-parameter sensitivity analysis showed that GQI index in Yazd-Ardakan plain is more sensitive to the components of electrical conductivity (EC), total dissolved solids (TDS), and total hardness (TH). Therefore, these components should be monitored more carefully and repeatedly.

Research Article

29/6/2015

The Potential of Sargassum oligocystum Harvested From Persian Gulf for the Adsorption of Copper Ions From Aqueous Solutions

Bahman Ramavandi, Ahmad Ebrahimi, Seyed Enayat Hashemi, Samad Akbarzadeh, Ghorban Asgari

This study revealed the potential of a brown alga, Sargassum oligocystum, harvested from Persian Gulf for the Cu²⁺ adsorption from aqueous solutions. The adsorption kinetic and isotherm and the characteristics of the biomass prepared from S. oligocystum (BSO) were investigated. The BSO was a mesoporous adsorbent with Brunauer, Emmett, and Teller (BET) surface area, a total pore volume, and an average pore diameter of 0.487 m²/g, 1.423 cm³/g and 12.5 nm, respectively. Fourier transform infrared spectroscopy (FTIR) analysis showed that there were many active functional groups such as alcohol and phenol groups, carbonyl, ethers, and esters on the BSO. Batch tests demonstrated that the Langmuir isotherm model best represented the equilibrium data with maximum copper ions adsorption capacity of 8.23 mg/g. Pseudo-second-order kinetic model was found to satisfactory describe the adsorption process. BSO is an easy-prepared adsorbent and could be an option for the treatment of Cu²⁺-laden wastewaters.

Research Article

30/6/2015

Simultaneous Removal of Turbidity and Humic Acid Using Electrocoagulation/Flotation Process in Aqua Solution

Abdolmotaleb Seid-Mohammadi, Zahra Sharifi, Amir Shabanlo, Ghorban Asgari

In this study, the applicability of the Electrocoagulation/Flotation (ECF) process in batch operation was investigated for the simultaneous removal of turbidity and Humic acid (HA) using Fe and Al electrodes. The effects of solution pH (3 - 12), electrical potentials (10 - 30 V), initial turbidity concentration (300 - 1200 NTU), and reaction time (10 - 30 minutes) with or without HA were investigated in an attempt to achieve higher turbidity removal efficiency. The batch experimental results revealed that with initial turbidity of 300 NTU, at voltage of 30 V, after 30 minutes reaction times, and at pH values of 6 and 8, the ECF process for Fe and Al electrodes removed over 97% and 88% of turbidity, respectively. The percentage of turbidity removal from solution dropped with a decrease in voltages for both electrodes. The results displayed that the Fe-Fe electrode arrangement attained the highest performance for turbidity removal rate. As a result, ECF process was shown to be a very efficient, cost-effective, and promising process for efficient treatment of high turbid water. Regarding HA, the results showed that in ECF process over 67% and 43% of UV254 has been removed for Al and Fe electrodes, respectively at the optimum pH, 30 minutes reaction time and 30 V applied voltage. Thus, it can be considered that Fe and Al are the best electrodes for removing turbidity and HA, respectively.

Letter

20/6/2015

Letter to the Editor: Regarding the “Simultaneous Removal of Turbidity and Humic Acid Using Electrocoagulation/Flotation Process in Aqua Solution”

Ghasem Azarian, Ali Reza Rahmani

Avicenna Journal of Environmental Health Engineering: Jun 2015, 2 (1), 8 articles.