Preparation Of A Kind Of Modified Sodium Humate Surfactant Based On Lignite

Humic substances are the main components of lignite and complex mixture of macromolecule composed of the unit of hydroxyl aromatic carboxylic acid.A kind of sodium humate surfactant with hydroxymethylation modification and esterification modification was presented in this dissertation.Firstly,hydrophilic modification was achieved by adding sodium hydroxide solution to dissolve humic substances given sodium humate,and the pH value of which was adjusted to alkaline conditions,reacted with paraformaldehyde to introduce hydroxymethyl group.Secondly,n-decanoyl chloride was added reacted with hydroxyl by esterification modification to achieve the purpose of hydrophobic modification.Finally sodium humate surfactant was prepared.The experimental results have been gotten as following:(1)The particle analysis of sodium humate was showed that particle size became smaller and dispersion was better than humic substances.It enhanced the reactivity of hydroxymethylation modification because of its homogenous conditions after alkaline pretreatment.(2)The acetyacetone spectrophotometry method was adopted to investigated the optimum conditions which were obtained that the amount of reacted paraformadehyde(mmol/g)was 6.23 when the reaction was carried out at 90 oC for 60 min in an environment of pH 10.5 with the dosage of formaldehyde/lignite(g/g)10:10.(3)Calibration curve of absorbance corresponding n-decyl chloride of different concentrations in petroleum ether was used for investigating the conversion rate of n-decyl chloride.The maximal conversion rate was up to 95% when the reaction was carried out at 70 oC for 10 h with the dosage of n-decyl chloride 6.0 mmol/g lignite.(4)The surface properties of humate surfactants was achieved that surface tension of solution decreased to 53.1 mN/m significantly and the corresponding cmc was 1.534 g/L,the maximum foaming height was 30 mm while sodium humate was 6 mm and the emulsifying properties was improved because separated time of 10 mL water was increased from 32 s to 132 s as compared with sodium humate.