Use of an iron-overexchanged clinoptilolite for the removal of Cu2+ ions from heavily contaminated drinking water samples

J Hazard Mater. 2008 Mar 1;151(2-3):738-45. doi: 10.1016/j.jhazmat.2007.06.047. Epub 2007 Jun 17.

Abstract

Clinoptilolite, a natural zeolite, was used for the synthesis of a high surface area clinoptilolite-iron oxide system, in order to be used for the removal of Cu2+ ions from drinking water samples. The solid system was obtained by adding natural clinoptilolite in an iron nitrate solution under strongly basic conditions. The Clin-Fe system has specific surface area equal to 151 m2 g(-1) and is fully iron exchanged (Fe/Al=1.23). Batch adsorption experiments were carried out to determine the effectiveness of the Clin and the Clin-Fe system in removal of copper from drinking water. Adsorption experiments were conducted by mixing 1.00 g of each of the substrates with certain volume of water samples contaminated with 10 different Cu concentrations (from 3.15x10(-5) to 315x10(-2) M or from 2.00 to 2000 ppm Cu). For our experimental conditions, the maximum adsorbed Cu amount on Clin was 13.6 mg g(-1) whereas on the Clin-Fe system was 37.5 mg g(-1). The main factors that contribute to different adsorption capacities of the two solids are due to new surface species and negative charge of the Clin-Fe system. In addition, the release of counterbalanced ions (i.e. Ca2+, Mg2+, Na+ and K+) was examined, as well as the dissolution of framework Si and Al. It was found that for the most of the samples the Clin-Fe system releases lower concentrations of Ca, Mg and Na and higher concentrations of K than Clin, while the dissolution of Si/Al was limited. Changes in the composition of water samples, as well as in their pH and conductivities values were reported and explained.

MeSH terms

  • Adsorption
  • Copper / chemistry*
  • Ions
  • Iron / chemistry*
  • Magnesium / chemistry
  • Models, Chemical
  • Potassium / chemistry
  • Sodium / chemistry
  • Waste Disposal, Fluid / methods
  • Water
  • Water Pollutants, Chemical / analysis
  • Water Purification / instrumentation
  • Water Purification / methods*
  • Water Supply
  • Zeolites / analysis
  • Zeolites / chemistry*

Substances

  • Ions
  • Water Pollutants, Chemical
  • Water
  • clinoptilolite
  • Zeolites
  • Copper
  • Sodium
  • Iron
  • Magnesium
  • Potassium