Abstract:
Textile industries release effluent that contains the vast majority of heavy metals and dyes
in which Cr (VI) and Congo red Dye is a toxic carcinogenic element that causes an
environmental problem. The work aims to synthesize algal-derived biochar using slow
pyrolysis at an operating temperature of 500 ℃, a heating rate of 10 ℃/min and a
residence time of 60 min and use it as an adsorbent to remove Cr (VI) and Congo red Dye.
The batch experiment was carried out using different concentrations of Cr (VI) and Congo
red Dye (1, 10, 25, 50, 100, 125, 150 and 200 ppm) at different intervals of time (2.5, 5,
10, 15, 30, 60, 120 and 240 min). The maximum removal percentage of Cr (VI) is 97.88
% and Congo Red Dye is 96.14029 % for the metal concentration of 1 ppm exhibiting
non-linear adsorption isotherm (Langmuir, Freundlich, Dubinin-Radushkevich, and
Temkin models) and kinetic models (pseudo-first order, pseudo-second order, nth order,
and intra-particular diffusion) were analyzed using a solver add-in of Microsoft Excel.
According to the results, the Langmuir isotherm model (R2 = 0.999, R2=0.996) and
pseudo-nth order models are suitable to describe the monolayer adsorption and the process
kinetics, respectively. The maximum adsorption capacity of algal biochar to adsorb is
186.94 mg/g for Cr (VI) and 179.9524 mg/g for Congo red Dye. For the prediction of
optimal removal efficacy, an artificial neural network of the MLP-2-7-1 (Cr (VI) and
MLP-2-5-1(Congo Red Dye) model was used. The results obtained are useful for future
work using algal biochar as an adsorbent of Cr (VI) and Congo Red Dye from textile
wastewater to achieve sustainable development goals.
