A study of the metal binding capacity of saccharinic acids formed during the alkali catalysed decomposition of cellulosic materials: nickel complexation by glucoisosaccharinic acids and xyloisosaccharinic acids

Abstract

The stoichiometry of the metal complexes formed between nickel and the ligand β-glucoisosaccharinic acid (β-GISA) and a racemic mixture of enantiomers of xyloisosaccharinic acid (XISA) has been determined at both neutral and alkaline pHs. Bjerrum plots, Job's plots and conductance measurements indicated that for each of the systems one to one Ni(ligand) complexes were formed at near neutral pHs (<7.5). At intermediate alkaline pHs (7.5-13) there is evidence to support the formation and precipitation of Ni2(ligand)(OH)3 complexes, finally, at high pH (>13) sparingly soluble Ni2(ligand)(OH)4 complexes were formed. The stability constants for the Ni(β-GISA), Ni(α-GISA) and Ni(XISA) complexes formed at neutral pH were determined under identical conditions using polarographic studies. The measured stability constants for Ni(β-GISA) (log10 β = 1.94 ± 0.15) and for Ni(α-GISA)(log10 β = 2.07 ± 0.13) are very similar; the value measured for the Ni(XISA) complex (log10 β = 0.83) was an order of magnitude smaller. The stability constants for the Ni2(Ligand)(OH)4 complexes formed at highly alkaline pHs were determined using the Schubert method. The measured stability constant for Ni2(β-GISA)(OH)4 (log10 β = 30.6 ± 0.5) was an order of magnitude bigger than the value for Ni2(α-GISA)(OH)4 (log10 β = 29.0 ± 0.5) measured under identical conditions. Attempts to measure the stability constant for Ni2(XISA)(OH)4 were unsuccessful; Ni2(XISA)(OH)4 complexes were not present in significant amounts at high pH to allow the log10β value to be determined by the Schubert method.

Crystal and solution structures of calcium complexes relevant to problematic waste disposal: calcium gluconate and calcium isosaccharinate

“…Under the highly alkaline conditions present in concretebased containers, cellulose breaks down into relatively lowmolecular-weight carboxylates and polyhydroxy carboxylates (Van Loon & Glaus, 1998). In the presence of calcium, the principal breakdown products, up to 80%, are approximately equal amounts of -d-isosaccharinate (-Isa À ) and its epimer -d-isosaccharinate (-Isa À ) (Van Loon & Glaus, 1998;Glaus et al, 1999;Knill & Kennedy, 2003;Almond et al, 2016). Research attention to date has focused almost entirely on -Isa À as the key ligand, in part because until recently -Isa À has been notably difficult to obtain (Van Loon & Glaus, 1998;Glaus et al, 1999;Knill & Kennedy, 2003;Almond et al, 2016;Shaw et al, 2012).…”

“…In the presence of calcium, the principal breakdown products, up to 80%, are approximately equal amounts of -d-isosaccharinate (-Isa À ) and its epimer -d-isosaccharinate (-Isa À ) (Van Loon & Glaus, 1998;Glaus et al, 1999;Knill & Kennedy, 2003;Almond et al, 2016). Research attention to date has focused almost entirely on -Isa À as the key ligand, in part because until recently -Isa À has been notably difficult to obtain (Van Loon & Glaus, 1998;Glaus et al, 1999;Knill & Kennedy, 2003;Almond et al, 2016;Shaw et al, 2012). Additionally, -Isa À has been found to be the more effective ligand (Shaw et al, 2012;Glaus & Van Loon, 2008), though recent work suggests this may depend on the metal in question (Almond et al, 2016).…”

“…Research attention to date has focused almost entirely on -Isa À as the key ligand, in part because until recently -Isa À has been notably difficult to obtain (Van Loon & Glaus, 1998;Glaus et al, 1999;Knill & Kennedy, 2003;Almond et al, 2016;Shaw et al, 2012). Additionally, -Isa À has been found to be the more effective ligand (Shaw et al, 2012;Glaus & Van Loon, 2008), though recent work suggests this may depend on the metal in question (Almond et al, 2016).…”

Sugarcane Bagasse Hydrolysis Enhancement by Microwave-Assisted Sulfolane Pretreatment

“…Further, during the pretreatment stage, other platform chemicals can be recovered [26]. For instance, saccharinic acids can be used for the preparation of various fine chemicals; as complexing agents for heavy metals [27], radionuclides and other materials; or as energy sources for aerobic and anaerobic bacteria [28].…”

The biogeochemical fate of nickel during microbial ISA degradation; implications for nuclear waste disposal

“…Microbially-mediated processes have been shown to control the fate of ISA, which can be used as an organic carbon source and electron donor for microbial metabolism, under a range of biogeochemical conditions, including nitrate and Fe(III) reduction at high pH 30 – 33 and neutral pH 34 , 35 . However, no studies to date have addressed the fate of radionuclide-ISA complexes, such as of Ni-ISA, which could potentially form under repository conditions, and have the potential to influence the properties of components in a GDF 16 , 36 . Furthermore biodegradation of Ni-ISA, could lead to sorption of the radionuclide, or its incorporation into new biominerals and sorption surfaces.…”