Pb2+ adsorption from aqueous solutions on activated carbons obtained from lignocellulosic residues

Abstract

-Activated carbons obtained from cane sugar bagasse (ACB), African palm pit (ACP) and sawdust (ACS) were prepared through an impregnated with HNO 3 and thermal treatment in an atmosphere in N 2 /steam water at 1173 K. Adsorption isotherms of N 2 at 77 K and of CO 2 at 273 K were determined for the activated carbons for which surface area and pore volume values were from 868 to 1100 m 2 g -1 and from 0.27 to 0.55cm 3 g -1 , respectively. These results were correlated, with the ones obtained for adsorption the adsorption isotherms of Pb 2+ in aqueous solutions. Impregnation of the lignocellulosic materials with nitric acid produced acid-type activated carbons with total acid site contents between 4.13 and 6.93 mmol g -1 and pH at the point of zero charge values between 2.7 and 4.1, which were within range of the adsorption, at different pH values, since they determined, the surface charge of the activated carbons. Adsorption isotherms of Pb 2+ at different pH values (2-8) at 298 K were determined. The ion adsorption capacity on ACB, ACP and ACS were 13.7, 15.2 and 17.5 mg.g -1 , respectively. Experimental data were fitted to the Langmuir and Freundlich models and all cases the former fit better. The highest values for the quantity adsorbed on the monolayer, qm, were at pH 4, whereas the surface, charge of activated carbons was negative and the lead species mainly present was Pb 2+ . For higher pHs, the quantity of Pb 2+ adsorbed decreased, and this had an important effect on adsorption, the surface characteristics of the solids and the hydroxilated lead species that were formed in the system.

Environmentally Benign Urea‐modifed Triticum aestivum Biomass for Lead (II) Elimination from Aqueous Solutions

“…As the pH increases, lead starts precipitating out as Pb(OH) 2 . This precipitation is unwanted as biosorption with biomass will not occur [18].…”

Characterization and use of in natura and calcined rice husks for biosorption of heavy metals ions from aqueous effluents

“…The use of RH for the sorption of metals in aqueous solution has been recently discussed due to its low cost, abundance, easy availability and possibility of reuse (Vieira et al, 2011;Kumar et al, 2010, Giraldo andMoreno-Piraján, 2008). Studies on metal removal using different adsorbents, such as clays (Vieira et al, 2010 a, b;Jiang et al, 2009), zeolites, sugarcane bagasse and other materials (Bhatnagar and Sillanpaa, 2010;Ahmaruzzaman, 2010;Gupta and Ali, 2004;Farooq et al, 2010;Garg et al, 2008;Kalderis et al, 2008;Sud et al, 2008) have been reported in the literature.…”

Adsorption of lead, ethylenediaminetetraacetic acid and lead-ethylenediaminetetraacetic acid complex onto granular activated carbon

“…Furthermore, though several investigations do report lead removal using different carbon based adsorption materials, including the traditional activated carbon (Taylor and Kuennen, 1994;Zhang et al, 2005;Issabayeva et al, 2006;Giraldo and Moreno-Piraján, 2008;Aghamohammadi et al, 2007), activated carbon cloths (Kadirvelu et al, 2000;Faur-Brasquet et al, 2002), carbon aerogel (Goel et al, 2005) and carbon nanotubes (Li et al, 2005) but studies reporting activated carbon initiated removal of lead in the presence of EDTA are few (Abdulkarim and Abu Al-Rub, 2004;Awwad et al, 2008;Krishnan et al, 2003;. Furthermore, most of these lead/EDTA activated carbon adsorption studies have focused only on lead removal with no detailed mention of EDTA's fate.…”