Removal of copper from aqueous solutions by phosphate rock

A study was carried out to examine the removal of copper from an aqueous solution by phosphate rock (PR). The adsorption method was applied and optimum conditions for adsorption were evaluated by changing various parameters; effects of pH, adsorbent concentration, initial metal concentration and contact time were investigated. The study shows that copper removal from an aqueous solution increases with increasing pH and adsorbent concentration (up to 5 g/l) and decreases with increasing initial copper concentration, and the equilibrium (contact) time was 40 min. The adsorption capacity of PR was determined as 0.17 mmol/g by fitting the experimental results to Langmuir and Freundlich isotherms. XRD analysis and infrared spectra analysis were used to characterize the mineralogical compositions of original and treated samples and the structural change on the sorbent after its treatment with 100 mg/l of copper (II), respectively. PR was found suitable as an adsorbent for removal of copper from aqueous solutions.

The conclusions obtained in this study are as follows: C Phosphate rock can be used as a sorbent for the removal of copper from aqueous solutions. C From the Langmuir isotherm, the maximum adsorption capacity of the PR sample was found as 0.17 mmol/g. C Langmuir and Freundlich isotherms are suitable for fitting the experimental findings. C Optimum adsorption conditions for copper removal are as follows: pH 5, contact time 40 min, adsorbent concentration 5 g/l. C A PR sample is efficient, especially for aqueous solutions containing low concentrations of copper (II).