Multi wall carbon nanotubes application for treatment of Cr(VI)-contaminated groundwater; Modeling of batch & column experiments.

Multi wall carbon nanotubes (MWCNTs) are carbonaceous nanomaterials with novel adsorption properties. In this study MWCNTs were used as adsorbents for hexavalent chromium, Cr(VI), and the influence of operating parameters, on adsorption process, such as pH, MWCNTs and Cr(VI) concentration, and contact time have been investigated. Batch and column experiments were carried out in order to investigate the removal efficiency of MWCNTs for different Cr(VI) concentrations related to groundwater polluted by either anthropogenic activities or by geogenic processes.

Chromium Removal Using Soil Loaded with Green Iron Nanoparticles.

Chromate is considered as a serious environmental problem due its toxicity. Iron nanoparticles produced by green tea polyphenols (GT-nZVI) is a powerful reductant, which can effectively reduce Cr(VI) to Cr(III). Nano ZVI suspension was initially conceived ideal for direct injection in the contaminated aquifers.

A DPSIR Approach to Selected Cr(VI) Impacted Groundwater Bodies of Central Greece.

The holistic approach of Driver-Pressure-State-Impact-Response (DPSIR) methodology was applied to selected Cr(VI) impacted groundwater bodies of Central Greece. The main driving forces in the study areas are agricultural activities, urban and industrial development as well as tourism. The main pressures induced by the anthropogenic activities are fertilizer use, uncontrolled urban sewage disposal and industrial effluents discharges.

Nanomaterials application for heavy metals recovery from polluted water: The combination of nano zero-valent iron and carbon nanotubes. Competitive adsorption non-linear modeling.

Carbon Nanotubes (CNTs) and nano Zero-Valent Iron (nZVI) particles, as well as two nanocomposites based on these novel nanomaterials, were employed as nano-adsorbents for the removal of hexavalent chromium, selenium and cobalt, from aqueous solutions. Nanomaterials characterization included the determination of their point of zero charge and particle size distribution. CNTs were further analyzed using scanning electron microscopy, thermogravimetric analysis and Raman spectroscopy to determine their morphology and structural properties.

Investigation of hexavalent chromium sorption in serpentine sediments.

In this study the removal of hexavalent chromium (Cr) by serpentine sediments was investigated in order to delineate Cr sorption behavior in aquifers with ultramafic geologic background. Batch experiments were conducted in order to determine the influence of several parameters on Cr removal, including the pH of the sediment solution, mineralogy, sediment's particle size and Cr initial concentration. The results showed that Cr removal was due to both adsorption and reduction phenomena.

The Origin of Hexavalent Chromium as a Critical Parameter for Remediation of Contaminated Aquifers.

Two different cases of Cr(VI) contaminated ophiolitic aquifers are presented herein. The first is located at Vergina (Northern Greece), where the maximum Cr(VI) concentration measured was 64 μg/L, being one of the highest geogenic concentrations recorded globally in areas with similar geological background. The second case is located at Inofyta (Central Greece), a makeshift industrial area, where the maximum detected Cr(VI) concentration exceeds 10,000 μg/L, indicating clearly anthropogenic activities as the main source.

Origin and concentration profile of chromium in a Greek aquifer.

In this paper the origin and concentration of chromium (Cr) in an ophiolitic aquifer in Vergina, northern Greece were investigated. The study area has only agricultural activity so that industrial Cr contamination was precluded. Soil sampling included topsoil and drillcore samples collected down to 98 m depth.

The role of activated carbon and disinfection on the removal of endocrine disrupting chemicals and non-steroidal anti-inflammatory drugs from wastewater.

Endocrine disrupting chemicals and non-steroidal anti-inflammatory drugs are two important groups of emerging pollutants due to their toxicological and chemical characteristics and their persistent detection in the aquatic environment. Wastewater treatment plants are a significant pathway for their transfer to the water courses. It is well evidenced that these chemicals are only partially removed through biological treatment of wastewater and therefore being detected in secondary effluents.