[en] This work was aimed to prepare Fe doped TiO₂ on an ionic liquid template so that nanoparticles (IL-Fe/TiO_2(Ar)) could be formed to degrade acetaminophen (ACE) using the photocatalytic process. The synthesized nanoparticles were characterized using XRD, DRS, FTIR and FESEM–EDX. IL-Fe/TiO_2(Ar) enhanced ACE photodegradation using the response surface methodology based on central composite design. The results evidenced that the presence of the 1-octadecyl-3-methylimidazolium bromide template led to development of nanocrystals with a uniform, small grain size. Moreover, the band gap energy calculated for IL-Fe/TiO_2(Ar) was observed to be 1.6 eV. The ANOVA results of the photodegradation process revealed a second term model with an adjusted R² equal to 0.996. The results also showed an ACE removal efficiency of 90.35% under optimal conditions (IL-Fe/TiO_2(Ar) dosage = 0.63 g/L, pH 9 and UV irradiation time = 90.35 min). According to the findings, the pseudo first order model was introduced to study photodegradation kinetics. The findings also yielded insight into the most effective variables on degradation of ACE, which were time, IL-Fe/TiO_2(Ar) and pH, respectively. Moreover, IL-Fe/TiO_2(Ar) had high potential for the removal of ACE by photodegradation and proved to be an appropriate method to obtain optimum operating conditions.

[en] The purpose of this study was to determine the removal efficiency of ciprofloxacin (CIP) by the combined electrochemical–persulfate (EC–PS) process using iron electrodes. The effects of contact time, initial CIP concentration, persulfate (PS) concentration, pH and current density in CIP removal were investigated. To measure the CIP removal mechanisms in the EC–PS process, radical scavenger analysis, EDS and FTIR were performed on the EC–PS process and produced sludge, respectively. Based on the results obtained, the EC process after 160 min can remove 38% of CIP, while the PS process had no effect on CIP removal. In contrast, the EC–PS process under the optimum conditions: current density of 1.45 mA/cm², PS concentration of 0.42 mM, pH of 5, CIP of 10 mg/L and contact time of 75 min, could reduce the antibiotic by more than 94%. Based on radical scavenger results, radical hydroxyl radicals play a major role in the EC–PS process. Also, by analyzing the results of radical scavenger, FTIR and EDS, it is suggested that the oxidation process was probably dominant in the early stages of the EC–PS process, and then, the electrocoagulation process played a basic role in CIP removal. The results of this study showed that the EC–PS process with a very good efficiency can be used to remove CIP antibiotics from aqueous solutions.

[en] Antibiotics, as one of the emerging pollutants, are non-biodegradable compounds and long-term exposure to them may affect endocrine, hormonal, and genetic systems of human beings, representing a potential risk for both the environment and human health. The presence of antibiotics in surface waters and drinking water causes a global health concern. Many researches have stated that conventional methods used for wastewater treatment cannot fully remove antibiotic residues, and they may be detected in receiving waters. It is reported that nanoparticles could remove these compounds even at low concentration and under varied conditions of pH. The current study aimed to review the most relevant publications reporting the use of different nanoparticles to remove antibiotics from aqueous solutions. Moreover, meta-analysis was conducted on the results of some articles. Results of meta-analysis proved that different nanoparticles could remove antibiotics with an acceptable efficiency of 61%. Finally, this review revealed that nanoparticles are promising and efficient materials for degradation and removal of antibiotics from water and wastewater solutions. Furthermore, future perspectives of the new generation nanostructure adsorbents were discussed in this study.

[en] The indiscriminate consumption of antibiotics and their introduction into the environment have caused global concerns. Typically, following consumption, these compounds are introduced into the environment after incomplete metabolism, and a large portion of them are impossible to remove using conventional wastewater treatment systems. The main aim of this study was to determine the feasibility of using a TiO₂/UV-C nanophotocatalyst doped with trivalent iron for the removal of amoxicillin from aquatic solutions. The nanophotocatalyst was prepared and characterized by SEM, XRD, EDX, DRS, and photoluminescence spectrum. The influences of different parameters, including nanocatalyst concentration (30–90 mg/L), initial concentration of amoxicillin (10–45 mg/L), and pH (3–11) at different time intervals (30–120 min) on antibiotic removal efficiency were investigated. Antibiotic concentration was measured with an HPLC device. All experiments were replicated three times according to the Standard Methods for the Examination of Water and Wastewater, 20^th edition. Data were analyzed using SPSS 19 and the ANOVA statistical test. Optimal conditions for removing amoxicillin from a synthetic solution were as follows: pH 11, initial concentration of antibiotic = 10 mg/L, nanocatalyst = 90 mg/L, and contact time = 120 min. The optimal conditions were also used to remove amoxicillin from Dana Pharmaceutical Company wastewater. The removal efficiencies of antibiotic for synthetic and pharmaceutical wastewater were 99.14 and 88.92%, respectively. According to the results, the nanophotocatalyst TiO₂/UV-C may be used for the removal of significant amounts of amoxicillin from pharmaceutical wastewater.

[en] p-Nitroaniline (PNA) is a common contaminant in the wastewater of oil refineries, the petrochemical industry and from production of pesticides, dyes and glue. The aim of this research was to determine the extent of degradation and removal of PNA from aqueous solutions by a novel semi-fluid Fe/charcoal reactor, process optimization, determination of the intermediate and final products and the degradation reaction path. The effective factors in the degradation process were contact time, aeration amount, initial PNA concentration, Fe/charcoal ratio, and initial pH of the solution. The intermediate products were determined by GC-MS. The kinetics of the degradation reaction also was determined. PNA removal efficiency in an actual sample from petrochemical industry wastewater was tested under optimal conditions. The maximum removal efficiency under the optimal conditions (pH: 7; contact time 120 min; aeration rate 10 L/min; Fe/charcoal ratio: 2/1; initial concentration of PNA: 10 mg/L) for the synthetic solution and in actual wastewater samples were 95% and 89%, respectively. In addition, the system stability was investigated in ten consecutive cycles of the electrode reuse. The removal efficiency decreased as low as 5%, which indicates the high stability of the system. The degradation process was determined to follow pseudo-first kinetics and the Langmuir-Hinshelwood model. Fe/charcoal micro-electrolysis is a relatively highly efficient system for removing PNA from wastewater and is suggested for this purpose.

[en] Ciprofloxacin (CIP) is a commonly used antibiotic which is excreted in significant quantities and may likely be found in environments, especially wastewater. Thus, in the present study, we aimed to remove CIP from aqueous solutions using activated carbon supported with multivalent carbon nanotubes MWCNTs/AC. Herein, we prepared the MWCNTs/AC and the structural characterization of the adsorbent was performed using the BET, FTIR, and SEM methods. In order to obtain the optimal conditions of MWCNTs/AC activity, different experimental conditions including the pH, adsorbent dosage, contact time, initial CIP concentration, and temperature were examined. Afterward, to approach reality, the experiments were carried out under the optimal conditions using a sewage sample previously determined in terms of the BOD, COD, pH, EC, turbidity, and concentration of ciprofloxacin. Finally, the CIP levels were measured by HPLC. According to the results, the pH of 7, contact time of 30 min, adsorbent dosage of 20 mg/L, temperature of 40 °C, and initial CIP concentration of 20 mg/L were found to be the optimal conditions for MWCNTs/AC activity. In these conditions, the maximum removal efficiency of CIP from the synthetic and actual samples was 100% and 73%, respectively. Moreover, the adsorption behavior was in compliance with the pseudo-second-order, Freundlich isotherm kinetics. According to our findings, using MWCNTs/AC led to a considerable removal of CIP from the sewage samples. Thus, the use of this adsorbent is highly recommended in order to remove other antibiotics from water and wastewater.

[en] Industrial wastewater needs to be treated because of the heavy metals presence and their effects on the environment. The aim of this study was to remove heavy metals ions such as copper and zinc from aqueous solutions by using Escherichia coli (E. coli) biofilm which was placed on zeolite. The paper was experimental. Synthetic and real samples were evaluated in laboratory scale. To evaluate the removal efficiency, the effective parameters such as pH, copper and zinc concentrations, and contact time were examined. Optimal conditions were obtained with experiments on the synthetic samples. To study the adsorption isotherms, Langmuir and Freundlich isotherm models were investigated. The copper and zinc cations maximum removal efficiency at 40 mg/L within 10 days was obtained as 54.61% and 57.35%, respectively. By using Langmuir isotherm, the experimental data were fitted with correlation coefficients of 0.98 and 0.95 for copper(II) and zinc(II), respectively. The results showed that the hybrid of zeolite and bacterial biofilm system has the best efficiency for removing the metal copper and zinc cations.

[en] Investigation of the quality of drinking water resources in terms of their effect on the human health is a vital issue. This study aimed to study physicochemical parameters in drinking water resources in NW Iran and made an effort to assess the health risk of these parameters. The study was conducted in winter, 2018 on the 16 sampling points in the vicinity of Lake Urmia, NW Iran. Heavy metals (Pb, As, Cd, Ni, Zn, and Cu) and ions (Na⁺, Ca²⁺, K⁺, NO₃⁻, SO₄²⁻, and Cl⁻) were measured by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and Ion Chromatography (IC), respectively. Non-carcinogenic risk and carcinogenic risk assessments were carried out by probabilistic approach and Monte Carlo simulation, and were expressed by hazard quotient (HQ) and excess lifetime cancer risk (ELCR) criteria, respectively. The mean values of pH, turbidity, and temperature and ions were within the permissible limits for drinking water according to the recommended range by World Health Organization (WHO). HQ values indicated a reasonable non-carcinogenic risk for Zn and Ni and unacceptable risks for As, Cd, and NO₃⁻. ELCR levels of As were unacceptably high. Finally, it was concluded that groundwater resources in the studied area did not have an acceptable quality for drinking usages due to the risk posed by As, Cd, and NO₃⁻. Therefore, pollution control through finding contamination sources and water treatment are recommended before the use of water resources for drinking consumption.