Contrasting Roles Of Natural Organic Matter On Colloidal Stabilization And Flocculation In Freshwaters

Controlled assembly of heterogeneous aggregates of clay, iron hydr(oxydes) and polysaccharide: Effects of preparation conditions

“…The apparent higher amount of adsorbed Dextran is related to the presence of nanoFeH on the surface of illite platelets, which leads to the following questions: what is the exact mechanism of aggregate formation and what is the exact role played by nanoFeH? The affinity of iron oxides for organic matter was reported in numerous studies (Reinhardt and Wilkinson, 2004;Cloy et al, 2014;Vindedahl et al, 2016;Sowers et al, 2018b), so that it is likely that the presence of nanoFeH enhanced Dextran adsorption. For Fe-montmorillonite heteroaggregates (Ji et al, 2004), it was suggested that the presence of FeH reduced the charge and electric field of clay particles.…”

Freshwater Suspended Particulate Matter – Key Components and Processes in Floc Formation and Dynamics.

“…(Buffle et al, 1998) The highly negative charge of HS results from many carboxyl-groups, which are deprotonated at environmental pH values. HS are generally thought to electrostatically stabilize colloids against aggregation, as adsorption increases negative charge of mineral surfaces or induces charge reversal of positively charged surfaces (Buffle et al, 1998;Reinhardt and Wilkinson, 2004;Srivastava et al, 2018). Adsorption of low-MW HS is kinetically favorable, but their hydrophilicity eases desorption and HS will be replaced by higher-MW, aromatic, hydrophobic NOM, the adsorption of which is thermodynamically favored (Philippe and Schaumann, 2014).…”

Zn, Ni, Cr, Cu, Fe e S em Iodo de esgoto: comportamento químico, adsorção e proposta de tratamento

“…Esse fato também é confirmado pela ausência da banda em 1.384 cm -1 , característica dos nitratos, que aparece ao final da compostagem (GRUBE et al, 2006 Figura 4-1 -Modelo de dupla camada elétrica de Gouy-Chapman-Stern-Grahame: (a) distribuição de cargas; (b) distribuição do potencial elétrico (JOLIVET, 1994 1 apud REINHARDT, 2004) No modelo de troca iônica, os prótons presentes nos grupos ligantes presentes na superfície sólida do adsorvente (R-COOH e R-OH) são substituídos por íons metálicos.…”