Abstract:
Contamination of water has become a global problem in the twenty-first century due
to the entry of both organic and inorganic toxins into the water system. Enormous
amounts of wastewater are discharged into the environment from the dyeing processes.
Because of their great chemical stability, industrial effluent from textile production
combined with insufficient dye degradation results in significant water contamination.
Dye-contaminated wastewater poses major health concerns, including cancer, as well
as problems for the aquatic environment. A common azo dye used in textile
manufacture and as an antibiotic is methyl red dye (MRD) which finds its way into the
water system when directly released or stray during the dyeing process. It is known to
be poisonous, carcinogenic, teratogenic, mutagenic, and cause respiratory issues.
Therefore, it is crucial to keep an eye on the quality of water. There is a need therefore
to remove these toxins from the environment and water. Coffee husks biochar (CHB)
was produced by gentle pyrolysis of coffee husks at 350 °C followed by characterization
using FT-IR, and SEM. Analysis using FT-IR revealed the vanishing of the O-H grop in
the coffee husks and the emergence of C=C, C=O, and C-O in the CHB indicating the
conversion of husks to biochar. Besides, the SEM investigation demonstrated a change
in the surface morphology of the CHB. In batch investigations, the impacts of CHB dose
(0.2-1.2 g), medium pH (1-12), time of contact (5-60) minutes, and initial dye
concentration (20-150 mgL
) were investigated. Coffee husks biochar demonstrated
remarkable efficacy in eliminating MRD with an impressive removal efficiency of up to
96.56% at optimum conditions. At pH 2 and 0.6 g of CHB, an adsorption equilibrium
capacity of 10.42 mg g
-1
-1
was reached in 25 minutes. Langmuir isotherm proved to be
the appropriate model for describing the MRD adsorption onto CHB, assuming a
chemisorption mechanism.
