scholarly journals Extended performance analysis of polyurethane–iron oxide nanocomposite for efficient removal of arsenic species from water

2016 ◽  
Vol 17 (3) ◽  
pp. 889-896 ◽  
Author(s):  
Faten B. Hussein ◽  
Nidal H. Abu-Zahra
Keyword(s):  
Iron Oxide ◽  
Operation Mode ◽  
Absorption Spectrometry ◽  
Arsenic Species ◽  
Removal Capacity ◽  
Pu Foam ◽  
Cyclic Operation ◽  
Removal Of Arsenic ◽  
20 Nm

A polyurethane (PU) foam nanocomposite impregnated with iron oxide nanoparticles (IONPs) was developed to remove arsenic (As) from drinking water at ppb concentrations. The effect of synthesis and application parameters such as the size of IONPs, pH levels, weight of adsorbents, and arsenic concentrations on the performance of PU-IONP adsorbents in removing arsenic were studied. The prepared adsorbents were characterized by scanning electron microscopy and energy dispersive X-ray microscopy to evaluate the microstructure of PU-IONPs and the surface adsorption of arsenic species, respectively. Atomic absorption spectrometry was conducted to measure the concentration of arsenic in the treated solutions in order to calculate the removal capacity of PU-IONPs. The experimental results revealed that decreasing the size of IONPs from 50–100 nm to 15–20 nm yields a higher removal capacity. Increasing the weight of the used adsorbents and the contact time led to an increase in the removal capacity as well. As the arsenic species (III and V) concentration increased in the solution, the removal capacity of PU-IONPs decreased. In a column study, a long-term cyclic operation mode was found to be very effective in removing arsenic; 100% removal capacity was achieved when 500 ml of As solution (100 ppb) was treated.

Removal of Arsenic in Drinking Water by Iron Oxide-Coated Sand and Ferrihydrite — Batch Studies

2001 ◽  
Vol 36 (1) ◽  
pp. 55-70 ◽  
Author(s):  
O.S. Thirunavukkarasu ◽  
T. Viraraghavan ◽  
K.S. Subramanian
Keyword(s):  
Drinking Water ◽  
Iron Oxide ◽  
Natural Water ◽  
Arsenic Concentration ◽  
Arsenic Species ◽  
Arsenic Adsorption ◽  
Batch Studies ◽  
Treatment Processes ◽  
Coated Sand ◽  
Removal Of Arsenic

Abstract Arsenic, a common toxic element is mainly transported in the environment by water. Arsenic in drinking water is of major concern to many of the water utilities in the world. Numerous studies have examined the removal of arsenic from drinking water through treatment processes such as coagulation-precipitation, reverse osmosis and ion exchange. The focus of research has now shifted to solve the problems using suitable adsorbents to achieve low level As in drinking water for communities with high raw water arsenic concentration. The determination of arsenic species is also essential for a better understanding and prediction of the toxic and carcinogenic nature of the species present in natural water systems. It is generally known that As(III) is more toxic than As(V) and inorganic arsenicals are more toxic than organic derivatives. The objective of this study was to study the arsenic adsorption behaviour on iron oxide-coated sand (IOCS) and ferrihydrite (FH). Batch studies were conducted using these adsorbents with natural water containing 325 μg/L arsenic, and the removal of approximately 90% was obtained. The adsorption capacity of the IOCS and FH used in this study for arsenic was estimated as 18.3 and 285 μg/g, respectively. The experimental data fitted well with the well-known isotherms, namely, Freundlich, Langmuir and BET, indicating a favourable adsorption by these adsorbents. Speciation studies were also conducted with natural water containing arsenic. Particulate and soluble arsenic in water were determined, and As(III) in the sample was determined by passing the sample containing arsenic through anion exchange resin (Dowex 1X8-100; acetate form) packed in the column. Speciation studies with natural water showed that the particulate and soluble arsenic contributed 11.4 and 88.6% of the total arsenic present in the natural water, respectively. In the case of soluble arsenic, As(III) and As(V) were 47.3 and 52.7%, respectively.

Characteristics of the Semiconductor Resistive Hydrogen Sensors in the Thermo-Cyclic Operation Mode

2014 ◽  
Vol 56 (12) ◽  
pp. 1427-1434 ◽  
Author(s):  
V. I. Gaman ◽  
Е. Yu. Sevast’yanov ◽  
N. K. Маksimova ◽  
А. V. Аlmaev ◽  
N. S. Sergeichenko
Keyword(s):  
Operation Mode ◽  
Hydrogen Sensors ◽  
Cyclic Operation

Long-term operation of electroactive biofilms for enhanced ciprofloxacin removal capacity and anti-shock capabilities

2019 ◽  
Vol 275 ◽  
pp. 192-199 ◽  
Author(s):  
Weifu Yan ◽  
Shuhua Wang ◽  
Rui Ding ◽  
Xiaochun Tian ◽  
Rui Bai ◽  
...  
Keyword(s):  
Term Operation ◽  
Removal Capacity ◽  
Ciprofloxacin Removal

scholarly journals Redox Oxides-Based Solar Thermochemistry and Its Materialization to Reactor/Heat Exchanger Concepts for Efficient Solar Energy Harvesting, Transformation and Storage

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Christos Agrafiotis ◽  
Mathias Pein ◽  
Dimitra Giasafaki ◽  
Stefania Tescari ◽  
Martin Roeb ◽  
...  
Keyword(s):  
Scanning Calorimetry ◽  
Chemical Expansion ◽  
Solar Energy Harvesting ◽  
Cyclic Operation ◽  
Heat Effects ◽  
Carbon Dioxide Splitting ◽  
Oxygen Pumping ◽  
Coefficient Of Linear Expansion ◽  
A Site

Ca-Mn-based perovskites doped in their A- and B-site were synthesized and comparatively tested versus the Co3O4/CoO and (Mn,Fe)2O3/(Mn,Fe)3O4 redox pairs with respect to thermochemical storage and oxygen pumping capability, as a function of the kind and extent of dopant. The perovskites' induced heat effects measured via differential scanning calorimetry are substantially lower: the highest reaction enthalpy recorded by the CaMnO3–δ composition was only 14.84 kJ/kg compared to 461.1 kJ/kg for Co3O4/CoO and 161.0 kJ/kg for (Mn,Fe)2O3/(Mn,Fe)3O4. Doping of Ca with increasing content of Sr decreased these heat effects; more than 20 at % Sr eventually eliminated them. Perovskites with Sr instead of Ca in the A-site exhibited also negligible heat effects, irrespective of the kind of B site cation. On the contrary, perovskite compositions characterized by high oxygen release/uptake can operate as thermochemical oxygen pumps enhancing the performance of water/carbon dioxide splitting materials. Oxygen pumping via Ca0.9Sr0.1MnO3–δ and SrFeO3–δ doubled and tripled, respectively, the total oxygen absorbed by ceria during its re-oxidation versus that absorbed without their presence. Such effective pumping compositions exhibited practically no shrinkage during one heat-up/cool-down cycle. However, they demonstrated an increase of the coefficient of linear expansion due to the superposition of “chemical expansion” to thermal-only one, the effect of which on the long-term dimensional stability has to be further quantified through extended cyclic operation.

A Simulation of Small Break Loss of Coolant Accident in Nuclear Heating Reactor Based on RELAP5

2018 ◽  
Author(s):  
Meng Lu ◽  
Heng Xie
Keyword(s):  
Thermal Power ◽  
Heat Removal ◽  
Injection System ◽  
Water Volume ◽  
Nuclear Heating Reactor ◽  
Removal Capacity ◽  
Loss Of Coolant ◽  
Nuclear Heating ◽  
Residual Heat

Nuclear heating reactor is integrated designed without main pump and safety injection system. The loss of coolant accidents are mainly in the form of small break LOCA. As no safety injection system is designed for coolant makeup, the water volume in the reactor vessel is critical since it determines whether the reactor will be submerged during the whole scenario. Therefore, the study on coolant loss in this pool system is indispensable. The RELAP5 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The long term effect in nuclear heating reactor is important. In this paper we investigated the influential factors on SBLOCA scenario and found the long term residual heat removal capacity is decisive in determining the loss of coolant. The residual heat removal capacity should be greater than 2% of reactor thermal power if ensuring the core submerged in the long run.

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