Revue sur l'enlèvement des métaux des effluents par adsorption sur la sciure et les écorces de bois

Abstract

Les résidus de transformation du bois tels les écorces et la sciure de bois ont été largement étudiés depuis quelques années pour leur propriété d'adsorption et d'enlèvement des métaux toxiques contenus dans les effluents contaminés. En ce qui concerne la sciure de bois, les recherches répertoriées ont porté principalement sur l'utilisation du sapin rouge, du manga, du tilleul, de l'épinette, du pin, du cèdre, du teck, de l'akamatsu et du buna. Pour ce qui est des écorces de bois, plusieurs espèces ont été étudiées, notamment les écorces de pin, de chêne et d'épinette. La présente revue fait le point sur les performances de ces différents adsorbants peu coûteux pour l'adsorption des principaux métaux contaminants (Cd, Cr, Cu, Hg, Ni, Pb et Zn). Les points discutés portent sur les méthodes de préparation (lavage, séchage et tamisage) et de traitement chimique de l'adsorbant (traitement acide ou basique, traitement à la formaldéhyde, phosphatation, carboxylation, sulfoéthylation, carboxyméthylation, etc.), les conditions opératoires utilisées lors de l'adsorption, les modèles thermodynamiques, cinétiques et autres applicables au couple adsorbant-adsorbat, l'effet des principaux paramètres opératoires (temps de contact, pH de traitement, température, concentration d'adsorbant, taille des particules, etc.), les principes et les mécanismes impliqués dans l'élimination des contaminants métalliques par les adsorbants présentés.Wood industry by-products such as barks and sawdusts have been widely studied in recent years for their property of metal adsorption and metal removal from contaminated effluents. Concerning the utilization of sawdusts, many researchers have studied metal adsorption on material from species such as red fir, mango, lime, pine, cedar, teak, Japanese red pine and Japanese beech. As regards wood barks, several species were studied, in particular pine, oak and spruce. The present review gives a progress report on the efficiency of these various inexpensive materials for the adsorption of different metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn). The points discussed relate to the preparation methods (washing, drying, screening) and the chemical treatments of the adsorbents (acid or base treatment, formaldehyde treatment, phosphatation, carboxylation, sulfoethylation, carboxymethylation, etc.). We also consider the operating conditions used during adsorption, the thermodynamic, kinetic and other models applicable to the adsorbent-adsorbate couple, the effect of the operational parameters (time of contact, pH, temperature, adsorbent concentration, particle size, etc.), as well as the principles and mechanisms involved in metal removal by the adsorbents.The accumulation of organic or inorganic matter at the solid-liquid interface is the basis of almost all surface reactions. Adsorption is often a process described in terms of isotherms, which represent the relationship between the concentration of a solute in solution and the quantity adsorbed at the surface at constant temperature. The isotherms are often used to...

Lead removal kinetics from synthetic effluents using Algerian pine, beech and fir sawdust’s: optimization and adsorption mechanism

“…In fact, the adsorption efficiency obtained with 5 g/L of solid/liquid ratio was 74 %; however, for 10, 20 and 30 g/L it was 96, 98 and 99 % respectively. The results are in agreement with similar previous study for heavy metal adsorption (Bouchemal and Achour 2007;Fiset et al 2001). However, the adsorption capacity (q e ) decreases as adsorbent dosage increases (Fig.…”

“…At high temperature and due to the large kinetic energy of particles, in the earlier time the possibility of collision between metal and adsorbent sites is higher; however, when reaching equilibrium the probability of collision and consequently fixation of metal ions become unprivileged because majority of sites on surface are occupied. As well, it was observed that at high temperature, adsorption sites can be subject to destruction or solubilization like the tannin onto sawdust as reported in Fiset et al (2001) revue and so the adsorption phenomenon is disfavored.…”

“…The initial pH value of solution is an important factor affecting the metal sorption because it may change the surface charge of the adsorbent (Gad et al 2013;Fiset et al 2001); so, it is necessary to determine the point of zero charge of the used adsorbent. As shown in Fig.…”

La bioadsorption sur amidon réticulé pour enlever des métaux des effluents industriels

“…On peut citer les biomasses algales (AKSU, 2005), la tourbe (McKAY, 1996) ou encore les déchets issus de l'industrie du bois (FISET et al, 2000). L'amidon fait également l'objet de nombreuses études dans la littérature.…”

Determination of the optimal conditions for the adsorption of cadmium ions and phenol on chestnut(Castanea sativa) shell

“…Adsorption has gained importance over other techniques such as precipitation, ion exchange, filtration or solvent extraction due to its good performance for removing contaminants from industrial effluents. On the other hand, there has been a constant search for new adsorbents among industrial and agricultural residues with high adsorption capacity and selectivity, abundant in nature and cheap (Bailey et al, 1999;Ho and McKay, 1999;Fiset et al, 2000;Calace et al, 2002;Rao and Viraraghavan, 2002).…”