Effect of pH on the removal of arsenic and antimony using reverse osmosis membranes

Václavíková

Science and Technology of Advanced Materials

et al. 2007

173

We present preliminary results of our joint investigations to monitor and mitigate environmental pollution, a leading contributor to chronic and deadly health disorders and diseases affecting millions of people each year. Using nanotechnology-based gas sensors; pollution is monitored at several ground stations. The sensor unit is portable, provides instantaneous ground pollution concentrations accurately, and can be readily deployed to disseminate real-time pollution data to a web server providing a topological overview of monitored locations. We are also employing remote sensing technologies with high-spatial and spectral resolution to model urban pollution using satellite images and image processing. One of the objectives of this investigation is to develop a unique capability to acquire, display and assimilate these valuable sources of data to accurately assess urban pollution by real-time monitoring using commercial sensors fabricated using nanofabrication technologies and satellite imagery. This integrated tool will be beneficial towards prediction processes to support public awareness and establish policy priorities for air quality in polluted areas. The complex nature of environmental pollution data mining requires computing technologies that integrate multiple sources and repositories of data over multiple networking systems and platforms that must be accurate, secure, and reliable. An evaluation of information security risks and strategies within an environmental information system is presented. In addition to air pollution, we explore the efficacy of nanostructured materials in the detection and remediation of water pollution. We present our results of sorption on advanced nanomaterials-based sorbents that have been found effective in the removal of cadmium and arsenic from water streams. r

Section: Water and Soil Contamination Remediationmentioning

confidence: 99%

Nanostructures in environmental pollution detection, monitoring, and remediation

Václavíková

Science and Technology of Advanced Materials

et al. 2007

173

ECS J. Solid State Sci. Technol.

“…25 The most widely studied adsorbents for the adsorption processes include iron hydroxides and oxides (such as amorphous hydrous ferric oxide, ferrihydrite and goethite). [26][27][28][29] Iron-based materials are very effective in the removal of arsenic (arsenate and arsenite).…”

mentioning

confidence: 99%

Magnetic Graphene Nanoplatelet Composites toward Arsenic Removal

Zhu

Sadu

Wei

et al. 2012

Magnetic graphene nanoplatelet composites (MGNCs) decorated with core-shell Fe-Fe 2 O 3 nanoparticles (NPs) have been synthesized using a facile one-pot thermal decomposition method. The graphene nanoplatelets (GNPs) decorated with uniformly dispersed NPs are observed to exhibit a strong magnetization and can be magnetically separated from the liquid mixture by a permanent magnet. These MGNCs demonstrate an effective and efficient adsorption of arsenic(III) in the polluted water due to the increased adsorption sites in the presence of magnetic NPs. The adsorption behavior is well fitted with both Langmuir and Freundlich models, which show a significantly higher adsorption capacity (11.34 mg/g) than the other adsorption values reported on the conventional iron oxide based adsorbents (∼1 mg/g). The results show a nearly complete As(III) removal within 1 ppb. © 2012 The Electrochemical Society. [DOI: 10.1149/2.010201jss] All rights reserved.Manuscript received March 8, 2012. Published July 17, 2012 Arsenic is known for its toxicity and carcinogenicity to human beings, 1-3 the contaminated water with arsenic is becoming a significantly increasing issue in drinking water throughout the world. Longterm exposure to arsenic can cause cancers of the bladder, lungs, skin, kidney, liver and prostate. 4 Arsenic contaminates include both natural and anthropogenic sources. Anthropogenic arsenic pollutants originate from mining and smelting of non-ferrous metals, burning of fossil fuels, usage of arsenic-containing pesticides in the agriculture 5 and arsenic-containing chemicals in the preservation of timber.6 Arsenic can exit in both inorganic and organic forms. In general, inorganic arsenic compounds are more toxic than organic arsenic compounds, and arsenite [As(III)] is considerably more mobile and toxic than arsenate [As(V)].7 Arsenate (i.e., HAsO 4 2− ) is the primary anion in the aerobic surface water and arsenite (i.e., H 3 AsO 3 or H 2 AsO 3 − ) is the primary species in the ground water. The actual valence states and chemical form, however, depend on the redox environments in the water systems including pH, oxidation-reduction potential, and the presence of complexing ions. There are several requirements that need to be met for arsenic removal such as safe and easy operation, high efficiency and low cost.7 Compared to the conventional water treatment techniques including oxidation/precipitation, 21 membrane/reverse osmosis, coagulation/coprecipitation, 22 and ion exchange, 7 adsorption has the following advantages. For example, it does not need a large volume or additional chemicals for treatment and it is easier to be deployed * Electrochemical Society Active Member.z E-mail: suying.wei@lamar.edu; zhanhu.guo@lamar.edu as a Point of Entry/Point of Use (POE/POU) arsenic removal process. Moreover, adsorption processes produce no sludge as met in the coagulation approach 7 and it does not need a strict control of pH values as met in the oxidation process.23 Adsorption can be dealt with low cost medium, low-tech operatio...

“…In general, arsenic removal efficiency increased slightly with increasing pressure. This can be attributed to an increase in permeate flux with increasing pressure, resulting in lower arsenic concentration in the permeate and subsequently improving As(V) rejection [9,19]. The concentration of As(V) in the permeate decreased with increasing pressure.…”

Section: Nf Membrane Structure and Performancementioning

confidence: 99%

Arsenic Removal from Drinking Water by Self-Made PMIA Nanofiltration Membrane

Zhao¹,

Du²,

Wang³

et al. 2012

ACES

A self-made PMIA asymmetric nanofiltration membrane was used for arsenic removal from drinking water by NF process. Effects of feed concentration, operating pressure, pH and existing ions on As(V) removal were investigated. Experimental results showed that As(V) rejection was higher than 90% in the range of investigated As feed concentrations. The As(V) rejection increased slightly with pressure increase, As(V) rejection was higher than 90% in the pressure range of 0.4 MPa to 0.8 MPa. As(V) rejection increased significantly from 83% at pH 3 to 99% at pH 9. The presence of NaCl enhanced As(V) rejection in the range of feed concentration, and As(V) rejection can reach up to 99% at a feed As concentration of 100 μg/L, whereas there was a rejection decrease of 8% in the presence of Na 2 SO 4 at every feed concentration. The results showed the As(V) detected in the permeate was lower than the EPA recommended MCL up to a feed As concentration of approximately 10 μg/L in the experimental research range.