Removal of RR-23 dye from industrial textile wastewater by adsorption on cistus ladaniferus seeds and their biochar

Abstract

The use of low-cost, easily obtained and eco-friendly adsorbents has been employed as an ideal alternative for the methods of removing dyes from wastewater. Cistus ladaniferus seeds (CLS) and their biochar (BCCLS) are the biomaterials used as a bio-adsorbent for removing of Reactive red 23 (RR-23). The bio-char of cistus seed is prepared by a thermo-chemical route known as pyrolysis under optimum conditions, temperature equal to 450 °C, heating rate 21 °C.min-1 and particle sizes of 0.3 to 0.6 mm after the BCCLS is grinded with a ceramic grinder until the particle size is between 0.1 and 0.2 mm. The kinetics adsorption of dye by CLS and BCCLS are correctly described by the pseudo-2nd-order model with a correlation factor (R2 = 0.997) and (R2 = 0.998) respectively. As for the modeling of the adsorption isotherm, among the four models tested, Lungmuir type II and type I is most appropriate with a correlation factor equal to 0.999 and 0.98 for the BCCLS and the CLS respectively. On the other hand, the ability to remove the dye by the BCCLS is advantageous and the elimination efficiency reaches a maximum value of 99.237% for the BCCLS and 82% for the CLS.

Keywords: Biochar, Isotherm, Adsorption, Cistus Seed, pyrolysis, Technical analysis.