Tartrazine dye removal with activated biochar produced from anaerobic sludge of an industrial wastewater treatment plant

[摘要] This study assessed tartrazine adsorption on biochar (BCA) produced from biological sludge of an industrial wastewater treatment system and activated with phosphoric acid and assisted by microwave energy. Characterization of BCA surface showed prevalence of hydroxyl groups (-OH) of carboxylic acid functional groups. Adsorption was studied in batch tests assessing pH, kinetic and adsorption capacity. Tartrazine adsorption was enhanced in acidic pH. In the kinetic tests, equilibrium occurred in 210 min with maximum adsorption of 9.87 mmg-1, while model fitting to models of second order, Elovich and intraparticle showed prevalence of chemisorption mechanism, surface energetic heterogeneity and adsorption involving more than one mass transfer mechanism. Results of isotherm test were adjusted to Freunlich, Temkin and Dubinin Raduskevich models, that showed little affinity between adsorbent and adsorbate, apparent free energy of 763.3 kJmol-1 and linear decrease of adsorption heat with the surface of the adsorbent.

[学科分类] 工程和技术（综合）

[关键词] Adsorption;Sewage Sludge;Activated biochar;Microwave energy