IWRA World Water Congress 2008 Montpellier France
1. Water availability, use and management
Mohamed Chiban *
(1): Equipe Matériaux, Photocatalyse et Environnement, Faculté des Sciences d’Agadir, BP.
8106 Cité Dakhla, Maroc
(2): Institut Européen des Membranes, CRNS, N°5635, 1919 Route Mende, 34293
* Corresponding author. Tel: + 21248220957, Fax
Carpobrotus edulis, Adsorption, Wastewater
treatment, heavy metals.
AbstractSeveral industrial wastewater
streams may contain heavy metals such as Cd, Cr, Cu, Pb, Zn, etc. including the waste liquids generated by metal
finishing or the mineral processing industries. The toxic metals must be effectively treated/removed from the
wastewaters. If the wastewaters were discharged directly into natural waters, it will constitute a great risk for the
aquatic ecosystem, whilst the direct discharge into the sewerage system may affect negatively the subsequent
biological wastewater treatment. In recent years, the removal of heavy metal from sewage, industrial and
miningwaste effluents has been widely studied. Their presence in streams and lakes has been responsible for several
types of health problems in animals, plants and human beings. Among the many methods available to reduce heavy
metal concentration from wastewater, the most common ones are chemical precipitation, ion-exchange, and reverse
osmosis. Most of these methods suffer from some drawbacks such as high capital and operational costs, incomplete
metal removal, low selectivity, high energy requirements. The aim of the present paper is to study the efficiency of a
new process for wastewater treatment by adsorption onto inert solid biomaterials (ISBM) using the batch
equilibration technique. These inert solid biomaterials are ground dried plants obtained from Carpobrotus edulis
plant. The results show that the inert solid biomaterials present a good retention of heavy metals and phosphate ions
from real wastewater. This retention increased with increasing of contact time. The removal percentage of heavy
metals from industrial wastewater by Carpobrotus edulis was 94 % for Cd, 91 % for Cu, 99 % for Pb and 98% for
Zn. The maximum adsorption capacity was depending on the type of ions (atomic weight, ionic radius and
electronegativity). The results indicate that the chemical oxygen demand (COD) values decrease after contact with
ISBM. The results obtained are compared with those obtained from -i) distilled water and -ii) from laboratory
solutions with various concentrations.
These results indicate that the inert solid biomaterials could be used for
removal of heavy metals and pollutant minerals from wastewater.