Adsorptive/desorptive potential of cationic basic yellow 28 (by28) dyes onto natural untreated clay from aqueous phase

Abstract

The adsorption of basic dye “C.I. basic yellow 28” (BY28) onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Tunisian raw clay sampled in Jebel Romana (meridional Atlas of Tunisia) composed mainly of smectite (52%) has shown efficiency for removal of BY28 from aqueous solutions. The results showed that basic pH is favorable for the adsorption of dye and adsorption. Adsorption isotherm was described by both Freundlich and Langmuir models. The maximum monolayer adsorption capacity was found to be 76.92mg/g at 25°C (at room temperature). Adsorption kinetics was studied and modeled. The maximum BY28 desorbed percentage was 17% and it was obtained for strong acidic conditions (pH 2). Smectitic clay showed to be an advantageous adsorbent in terms of price and versatility, being effective under a wide pH range, for cationic dye. Its use as adsorbent does not require further purification or chemical modifications, which is beneficial for the environment and for the economy of the treatment.