Sodium-Treated Iron-Bridged Clay for Arsenic Removal in the Presence of Lead and Cadmium: A Comparative Study
Kouadio Lucas Moses *
Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire.
Bargiela Pascal
Université de Pau et des Pays de l’Adour, E2S UPPA, CNRS UMR 5254, IPREM, Pau, France.
Kouamé Niamien Alfred
Laboratory of Constitution and Reaction of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, Abidjan, Ivory Coast.
Larregieu Marie
Université de Pau et des Pays de l’Adour, E2S UPPA, CNRS UMR 5254, IPREM, Pau, France.
Sei Joseph
Laboratory of Constitution and Reaction of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, Abidjan, Ivory Coast.
Martinez Hervé
Université de Pau et des Pays de l’Adour, E2S UPPA, CNRS UMR 5254, IPREM, Pau, France, Ecole Centrale Casablanca ECC, Centre Systèmes Complexes et Interaction, Bouskoura, Morocco and Centrale-Supelec, Université Paris-Saclay, Gif-sur-Yvette, France.
Pannier Florence
Université de Pau et des Pays de l’Adour, E2S UPPA, CNRS UMR 5254, IPREM, Pau, France.
*Author to whom correspondence should be addressed.
Abstract
Contamination of environmental matrices by trace metals is mainly due to human activities. One of the chemical species released into the environment and hazardous to living organisms is arsenic. The present work aimed to study the elimination of arsenic in the presence of lead and cadmium using a sodium-treated, iron-bridged Ivory Coast clay. To achieve this goal, the fine fraction of a smectite-rich clay from Katiola in Côte d'Ivoire was extracted and treated with sodium (KAT-Na). In addition, this sodium-treated clay was iron-bridged (KAT-Na-Fex(OH)y). The clay was bridged by adding the bridging solution (Fex(OH)y) drop by drop to a clay suspension (0.5% w/v concentration) under constant agitation. Samples were analysed by XPS. For the analysis of clays using XPS - X-ray Photoelectron Spectroscopy, the Escalab 250 Xi ThermoFisher spectrometer was used. Survey spectra were recorded in a range from 1350 to 0 eV, with a passage energy of 140 eV. High-resolution spectra were recorded for the photoemission peaks Fe 2p3/2,1/2, K 2p3/2,1/2, O 1s, C 1s, Cl 2p3/2,1/2, Si 2p3/2,1/2 and Al 2p3/2,1/2. KAT-Na and KAT-Na-Fex(OH)y clays were used to adsorb arsenic in aqueous solution. The method used was that of batch adsorption. Arsenic was determined by ICP-AES. For an initial concentration ranging from 0 to 20 ppm, arsenic removal on KAT-Na clay reached 73.64%. In contrast, bridging the clay with iron significantly improved the arsenic removal rate, reaching 91.75%. The adsorption isotherms plotted indicate that arsenic removal on KAT-Na is best represented by the Langmuir model. Whereas Freundlich linearization better describes arsenic adsorption on KAT-Na-Fex(OH)y clay. The presence of metal cations (Cd and Pb) did not prevent good arsenic removal. The higher Qmax of KAT-Na-Fex(OH)y than KAT-Na confirms that the bridged clay has a better adsorption capacity. The values of n and RL lie respectively in the intervals ]1; 10[ and ]0; 1[. These results suggest that the adsorption of arsenic in the presence of lead and cadmium on KAT-Na and KAT-Na-Fex(OH)y clays is favourable. This research contributes to the treatment of water to improve the health of living beings, using iron-bridged Katiola clay as an adsorbent.
Keywords: Clay, bridged clay, smectite, adsorption, arsenic