Caffeine removal using Elaeis guineensis activated carbon: adsorption and RSM studies

• Published in: Environmental science and pollution research international Vol. 27; no. 21; pp. 27048 - 27060
• Main Authors: Melo, Larissa L. A., Ide, Alessandra H., Duarte, José Leandro S., Zanta, Carmem Lucia P. S., Oliveira, Leonardo M. T. M., Pimentel, Wagner R. O., Meili, Lucas
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-07-2020; Springer Nature B.V
• Subjects: Activated carbon; Adsorbates; Adsorbents; Adsorption; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Brazil; Caffeine; Caffeine - analysis; Charcoal; Charge materials; Chemisorption; Design of experiments; Earth and Environmental Science; Ecotoxicology; Elaeis guineensis; Environment; Environmental Chemistry; Environmental Health; Environmental science; Experimental data; Experimental design; Fourier analysis; Fourier transforms; Hydrogen-Ion Concentration; Infrared analysis; Infrared spectroscopy; Kinetics; Mathematical models; Optimization; Petroleum production; Research Article; Research Design; Response surface methodology; Scanning electron microscopy; Spectroscopy, Fourier Transform Infrared; Statistical models; Thermodynamics; Thermogravimetric analysis; Variance analysis; Waste Water Technology; Water Management; Water Pollutants, Chemical; Water Pollution Control; Brazil; Biochar; Wastewater; Emerging pollutants; Pharmaceuticals
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-09053-z

The palm (
Elaeis guineensis
), known as
dendê
, is an important oleaginous Brazilian plant with a high performance of oil production. In this work, a 2
3
full experimental design was performed and the response surface method (RSM) was used to indicate the optimum parameter of caffeine adsorption on
Elaeis guineensis
endocarp activated carbon, since the endocarp is the main by-product from
dendê
oil production. It was set the adsorbent point of zero charge (pH
pzc
), and the material was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The RSM results indicate removal efficiency (%) at the optimal conditions, 0.20 g of adsorbent, and caffeine initial concentration of 20 mg/L, and acidic medium was about 95%. Based on ANOVA and
F
test (
F
calculated
>
F
standard
), the mathematical/statistical model obtained fits well to the experimental data. The overall kinetic studies showed time was achieved after 5 h and caffeine adsorption followed the pseudo-second-order model suggesting chemisorption is a predominant mechanism. Redlich-Peterson and Sips models best represented the experimental data (0.967 <
R
2
< 0.993). Thermodynamic revealed that caffeine adsorption was spontaneous at all temperatures studied, exothermic, and probably with changes in the adsorbate-adsorbent complex during the process. The tests conducted in different water matrixes corroborate the suitability of this adsorbent to be used in caffeine removal even in a complex solution.