Removal of BTEX from aqueous solutions by paper mill sludge-based activated carbon

The removal of BTEX (benzene, toluene, ethyl-benzene and p-xylene) from contaminated groundwater was evaluated by paper mill sludge-based activated carbon, prepared by chemical activation and pyrolysis.The effects of pH, time, adsorbent dosage and adsorbate concentration were studied through batch adsorption experiments. Selected physical and chemical characteristics of the adsorbents, such as specific surface area (613m2/g), pore volume distribution (micropore: 277cm3/g, mesopore: 365cm3/g) and surface functional groups (carboxylic, alkyl and aliphatic groups) were determined by N2 adsorption-desorption diagram and FTIR, respectively. The removal efficiency of the four target compounds would be more than 92 %, which the initial concentrations of BTEX and the adsorbent dosage were 40 mg/l and 1000 mg/l, respectively. It was proved that pH and ionic strength have insignificant effects on the adsorption efficiency. The order of adsorption amount in all experiments was > ethyl-benzene > toluene > benzene. The kinetic data proved a closer fit to the pseudo-first-order model. The isotherm experimental data showed a better fit to either Freundlich or Langmuir model. In addition, a series of experiments was conducted to evaluate the capacity of the adsorbent in adsorbing the BTEX from a groundwater sample contaminated with gasoline

Histological Study of the Placenta in Neonates With Intrauterine Growth Retardation

Objective: Placenta is the maternofetal contact zone, provided by normal membranes and endometrium, for which the intrauterine fetal life depends on. Regarding the importance of placenta in embryonic period, this study aims at investigating the histopathological changes of placenta in newborns with intrauterine growth retardation (IUGR). Materials and Methods: This study was performed on two groups (control and experimental) of pregnant women with IUGR fetus in the Histological Department of Medical School of Azad University, Tabriz. In the experimental group, 30 samples of IUGR placentas were examined. The samples were first fixed in formalin, embedded in paraffinized mold, and cut into 5 μm sections. After that, the samples were prepared for staining with Hematoxylin and Eosin (H&E), trichrome, and PAS techniques. Results: Findings showed the increase of syncytial knots and fibrinoid, the presence of villous fibrosis, and decrease of glycogen deposit in the experimental group. In addition, statistical investigations suggested that placental and fetal weights in the experimental group were significantly lower than control group (P < 0.05). Conclusion: The results obtained from this study showed that fetal placental and birth weights were lower than control group. Pathological results showed increase of syncytial knots and fibrinoid in the experimental group in comparison to control group

Monitoring of fisheries resources in artificial reefs in east of Kish Island waters

Artificial reefs are manmade materials deployed under water in order to improve environment and increase the exploitation of fishing area. Usage of artificial technic has developed due to increase of world population and need to supply of protein, aim to restoring of natural specially rehabilitation of demersal fishes. It has effected to increase the production in order sustainable exploitation. Coasts and Islands have destruction due to over harvesting from ecosystems and other activities by humans and natural, these caused many aquatic as demersal fishes has endangered in Persian Gulf and Oman Sea. The artificial reef is one way or method that can improve the environment and restore the aquatic. Iranian fisheries has established an artificial reefs area in west of Kish Island. This area has studied during one year, Data of assembled fishes and physical sampling were collected in seasonal during spring, summer, autumn and wintered. There were tow treatment for sampling as artificial reefs site and a control site. Collected data has analyzed and evaluated by SPSS and Exel. The results showed that there was significant difference between the sites and assembled fishes in artificial reefs were more than control site. Consequently the artificial reefs can be a tool and technic to improve the marine environment and increase the production of fishes, especially the demersal fishes

STAGNATION REDUCTION IN DRINKING WATER STORAGE TANKS THROUGH INTERNAL PIPING

Poor mixing in storage tanks can cause stagnant zones that could pose negative public health effects. To eliminate stagnant zones in a cylindrical water storage tank, this study investigated the feasibility of a novel internal piping configuration consisting of a sprinkler-type inlet piping that distributed the incoming flow evenly across the water surface and a corresponding upside-down sprinkler draining configuration at the tank bottom. The experiments were conducted on seven types of inlet and outlet configurations. Experiments were performed using an acoustic Doppler velocimeter (ADV) and electrical conductivity (EC) measurements. Various stagnation metrics, like the time for the water to be well-mixed and water particle velocity and direction, were employed for each configuration. In addition, a new metric is introduced to evaluate short circuiting conditions in storage tanks. Inlet/outlet convergence time is a simple indicator, in which the lower the value, the higher the risk of short-circuiting. In the next step, experiments were performed with a temperature difference between the tank and the inflow due to density-driven flows. Results indicated that the novel piping resulted in parallel downward streamlines that eliminated most of the stagnation zones in the tank. Next, we studied life cycle assessment (LCA) of three options available to solve water stagnation in storage tanks. Using a 20-year period of time as a baseline for the manufacture and operation of mixer, multiple inlets, and sprinkler systems. These options were compared using different life cycle assessment (LCA) tools. Using SimaPro modeling software as well as IPCC 2013 GWP 100a V1.0, Cumulative Energy Demand methods, and Eco-indicator 99 these three types of mixing approaches were compared with and without waste recycling. In addition to the LCA, cost analysis showed that application of a sprinkler is the least expensive option. Damage- cost analyses for categories of human health, ecosystem quality and resources showed that a sprinkler caused the least damage and cost, while a mixer resulted in the most damage and cost. Finally, in continuation of our previous studies to address this problem using sprinklers as the inlet and outlet, Computational Fluid Dynamics (CFD) modeling was used to investigate more cases and come up with design suggestions. The CFD modeling results using a K-ϵ model were verified with experimental results. Then, the sprinkler system was applied to a spherical tank and the results were compared with the same tank employing an angled-nozzle sprinkler system as the inlet. Results showed the superiority of the angled-nozzle sprinkler system. The introduction of different temperature water to the tank was used to measure the well-mixed time. Using this mixed-time indicator, the effect of height to diameter ratio (H/D) on cylindrical tanks employing a sprinkler system as their inlet and outlet was investigated and two equations were suggested for H/D less than and greater than 0.75, with the former resulting in faster mixing

Using recyclable magnetic carbon nanotube to remove micropollutants from aqueous solutions

© 2017 Elsevier B.V. Magnetic carbon nanotubes (MCNs) were synthesized using a new hydrothermal method. The new developed MCNs were evaluated for removal of Metolachlor, Bisphenol-A, Tonalide, Triclosan, Ketoprofen and Estriol from aqueous solutions. Using response surface methodology, a predicting removal model was developed based on solution pH, contact time, adsorbate concentration and adsorbent dose. Experimental results showed high agreement with the predicted ones at optimum conditions. In addition, experimental results were modeled by Freundlich and Langmuir isotherms, which directed a better fit to the Langmuir isotherm. MCN presented good adsorption capacity in which Bisphenol-A, Ketoprofen and Tonalide were the most effectively removed micropollutants, with 98, 96 and 96% removal within 47 min, respectively. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous for the micropollutants. Adsorbate regeneration studies were done with methanol, ethanol, HCl, NaOH and hydrogen peroxide in five regenerating cycles. Methanol had the highest level of adsorbent recovery. MCN can be used as a sustainable adsorbent for adsorption of the studied micropollutants

Effects of oxalate and persulfate addition to Electrofenton and Electrofenton-Fenton processes for oxidation of Ketoprofen: Determination of reactive species and mass balance analysis

© 2018 Elsevier Ltd Electrofenton (EF) has been widely used to remove contaminants from aqueous solution, while Electrofenton-fenton (EFF), is a two stage process that employs partial electrolysis, needs further study. In addition, a combination of oxalate and persulfate with these systems (EF-Oxalate, EFF-Oxalate, EF-Persulfate, and EFF-Persulfate) could improve the oxidation capacity. This study assessed the applicability of these systems for degradation of Ketoprofen as an emerging contaminant. Under batch experiments, results showed that the order of oxidation capacity and mineralization is EF-Persulfate \u3e EFF-Persulfate \u3e EF-Oxalate \u3e EFF-Oxalate \u3e EFF \u3e EF. Radical scavenger experiments indicated that [rad]OH is the dominant radical species in EF, EFF, EF-Oxalate, and EFF-Oxalate systems. However, both [rad]OH and 1O2 participated in oxidation of Ketoprofen in both EF-Persulfate and EFF-Persulfate processes. Fe(II)/Total Fe ratios in both solution and sludge samples decreased as oxidation capacity enhanced. Solution and sludge analyses revealed that the amount of Ketoprofen and oxidation byproducts increased in sludge over time. Carbon mass balance calculations showed that EF-Persulfate leaves the lowest amount of oxidation by-products in the system. BOD5/COD ratio analyses demonstrated that all studied systems improved biodegradability of the raw wastewater. EFF and EF-Persulfate systems had the lowest and highest operational costs, respectively. Competitive maps were developed to compare all six processes by Ketoprofen removal efficiency, mineralization capacity, and operational costs. Results confirmed that addition of oxalate and persulfate to EF and EFF systems provide good solutions to decrease the load and risk posed by Ketoprofen to water systems

Sustainable life-cycle assessment of mixing approaches in water storage tanks

Poor mixing in water storage tanks can cause stagnant zones that could pose negative public health effects. The present study uses Life Cycle Assessment to decide among the only three mixing options available, namely sprinkler, multiple inlets, and a mechanical mixer for the first time. These options were compared using different life-cycle assessment (LCA) tools using an 80-year lifetime as the functional unit while assuming that all three options result in acceptable water quality. Using SimaPro modeling software as well as the IPCC 2013 GWP 100a V1.0 and Cumulative Energy Demand methods, these three mixing approaches were compared with and without waste recycling. Results showed that application of a sprinkler is the least expensive option. Damage-cost analyses for categories of human health, ecosystem quality, and resources showed that a sprinkler caused the least damage and cost, while a mixer resulted in the most damage and cost

Simple device to improve mixing in storage tanks

Algae and bacteria can grow in water storage tanks when the water is stagnant. Although many variations of storage tank exist, many have the inlet and outlet pipes at the tank bottom. Stagnation occurs in the top portion of the tank from which water is not used since it is kept for emergencies only. A simple and passive method was developed in this study that mixes water in the entire tank without using electricity like mechanical mixing devices. The new device consists of a riser pipe in the tank center that leads to eight-arm sprinkler-type piping that extends above the entire tank surface. Diffuser holes are located along the bottom of all the sprinkler arm pipes from which water falls even along the entire tank surface. To ensure that all water particles fall directly down and thereby mix all the tank’s water a corresponding “inverse sprinkler” is used for drainage out of the tank. This drainage sprinkler has eight arms with the same location of holes as the top sprinkler, this time on the top of the piping for the eight arms. The device requires only some additional piping be put into an existing or new tank. The new piping is low cost, since it could be from commercially-available seizes and material such as PVC. Laboratory experiments were conducted both with and without the new mixing device. Dye testing and detailed three-dimensional acoustic Doppler velocimeter measurements show a significant increase in mixing throughout the tank with no stagnation zones to allow the growth of algae or bacteria, thereby improving public health. The new device, therefore, is concluded to be an effective and passive and sustainable way to eliminate stagnation in water storage tanks and thereby improve public health

CFD modeling of stagnation reduction in drinking water storage tanks through internal piping

Poor mixing is considered to be the main reason for stagnation in water tanks. This can pose threats to public health. Internal tank piping with sprinklers (distributed outlets) has been previously proposed to avoid flow stagnation. This study is the first to use Computational Fluid Dynamics (CFD) modeling to investigate more cases and come up with design suggestions. The CFD modeling results using a realizable k-ϵ model were verified with experimental results for a limited number of cases involving the sprinkler system. The CFD model was used to investigate various tank aspect ratios and spherical tanks. Results showed the superior mixing of an angled-nozzle sprinkler system for spherical tanks. The effect of height-to-diameter ratio (H/D) on cylindrical tanks employing a sprinkler system as their inlet and outlet were investigated and two equations were suggested for prediction of mixing. These showed that for H/D less than 0.75 there was faster mixing

Using polymer coated nanoparticles for adsorption of micropollutants from water

© 2017 Elsevier B.V. In this study, polyvinylpyrrolidone (PVP)-coated magnetite nanoparticles were synthesized to adsorb six emerging contaminants (Tonalide, Bisphenol-A, Triclosan, Metolachlor, Ketoprofen and Estriol) from aqueous solutions. The PVP-coated NPs were characterized by dynamic light scattering (DLS) measurements, thermal analysis, and X-ray diffraction. Results indicated that PVP-coated NPs were successfully used as a separable adsorbent for removing the micropollutants from water. Adsorption results were modeled using Langmuir and Freundlich isotherms, which showed a better fit of data to the Langmuir model. The adsorbent showed good adsorption performance in which Bisphenol-A and Ketoprofen were the most effectively removed micropollutants, with 98 and 95% removal using only 0.1 mg of the adsorbent within 15 min of contact time, respectively. Kinetic studies were performed using the pseudo-second-order model to compare the performance of PVP-coated NPs with granular activated carbon (GAC) revealing the superiority of PVP-coated NPs over GAC. Thermodynamic parameters of the adsorption of the micropollutants onto the adsorbate showed the adsorption process was endothermic and spontaneous. Adsorbate regeneration studies were performed with methanol, ethanol, and the UV/H2O2 process in five regeneration cycles. Methanol treatment ensured the highest level of regeneration