Highly improved chromium (III) uptake capacity in modified sugarcane bagasse using different chemical treatments

Abstract

The present paper focuses on improving chromium (III) uptake capacity of sugarcane bagasse through its chemical modification with citric acid and/or sodium hydroxide. The chemical modifications were confirmed by infrared spectroscopy, with an evident peak observed at 1730 cm-1, attributed to carbonyl groups. Equilibrium was reached after 24 h, and the kinetics followed the pseudo-second-order model. The highest chromium (III) maximum adsorption capacity (MAC) value was found when using sugarcane bagasse modified with sodium hydroxide and citric acid (58.00 mg g-1) giving a MAC value about three times greater (20.34 mg g-1) than for raw sugarcane bagasse

Adsorption kinetics, isotherms and thermodynamics of Cr(III) on graphene oxide

“…At pH < 4.0, The adsorption of Cr(III) increased slowly, followed an abrupt increase at pH 4.0-5.5, and then reached a plateau at pH > 6.0. At low pH, the low adsorption capacity of Cr(III) can be attributed, in part, to the competition between the excess proton in solution and Cr(III) for the same binding sites on GO surface [29]. An increase of solution pH increased the number of negatively charged sites on GO surface, which further facilitated the adsorption of cationic Cr(III).…”

“…Undoubtedly, the increased negative charged sites on GO promoted the adsorption of Cr(III) through electrostatic attraction and/or complexation. When solution pH increased, the percentage of free Cr ion decreased, while the percentage of hydrolyzed Cr(III) species increased [29]. According to Mclean and Bledsoe [30], hydrolyzed Cr(III) species more tended to be adsorbed on GO than that of free Cr(III) ion.…”

“…This may be another reason about the pH dependence of Cr(III) adsorption on GO. Increasing [29]. In this study, to make sure the maximum adsorption efficiency as well as to avoid precipitation of Cr(III), all the following experiments were conducted at pH 5.0.…”

Adsorption Study of Pb(II), Cd(II), Cu(II) and Cr(III) ions in Aqueous Medium using C-4-Hydroxy-3-methoxyphenylcalix[4]resorcinarene Dodecaacetate

“…These results can be explained by considering electronic interaction between the adsorbent and the speciation of metal ions [26][27][28] in different pH. In term of metal speciation, both Pb and Cd are mainly existed as Pb 2+ and Cd 2+ under pH 6.…”

Adsorption Study of Pb(II), Cd(II), Hg(II) And Cr(III) Onto Calix[4]Resorcinarene Derivative

“…32 While the major species of Cr(III) at low pH is Cr and CrOH 2+ are observed in the pH range 4-6. 33 The predominant Hg species at pH < 4 is HgCl 2 and at pH > 4 is Hg(OH) 2 . 34 At low pH, both adsorbent and metal ions were existed as positively-charged species.…”