Removal of Zn(II) in Synthetic Wastewater Using Agricultural Wastes

Abstract

In the present investigation, results obtained from the process of the biosorption of Zn(II) in synthetic wastewaters are presented, using three agricultural wastes (coffee pulp, banana pseudo-stem, and corncob). Firstly, the percentage of lignin and cellulose for each material was determined. Then, using the free software XLSTAT, the waste with the highest removal for this metal was selected and, after this, the optimum pH, kinetics, adsorption isotherm, and point of zero charge (pHpzc) were found. Finally, a comparison with other lignocellulosic materials derived from banana, corn, and coffee crops was carried out. According to the results obtained, coffee pulp was the material that showed a high removal compared to the other two (63.58%), for which the optimum pH was 5.0 units. The kinetic model, which was adjusted to the process of biosorption, was the pseudo second order of Ho and McKay, which in turn presented an isotherm of Langmuir’s linearized model where the maximum adsorption capacity with that waste was 13.53 mg × g−1, obtained with a particle size of 180 µm, contact time of 90 min at 100 RPM, temperature of 25 °C, and pHpzc 3.95 units. Lastly, the authors state that this type of agricultural waste can be used as a green technology in the treatment of wastewater, particularly in the removal of the aforementioned pollutant, in order to fulfill goals 3.9 and 6.9 of the Sustainable Development Goals of the 2030 Agenda; to the level of challenge of the research, the authors propose for the future to carry out the implementation of this type of waste, without chemical modification, in the treatment of wastewater for the removal of the mentioned pollutant in a pilot study with different wastewaters and industries.

Removal of Zinc from Concentrated Galvanic Wastewater by Sodium Trithiocarbonate: Process Optimization and Toxicity Assessment

“…Other studies indicated that the application of an electrocoagulation process for high strength industrial electroplating wastewater (pH 2, COD 1 430 mg O 2 /L, Ni 150 mg/L, Cu 30 mg/L, Zn 25 mg/L and Fe 2.9 mg/L) made it possible to remove 92.1% Ni, 87.8% Zn and 82.9% Cu [ 59 ]. In the case of using agricultural wastes as adsorbents, the highest efficiency of zinc removal (63.6%) was obtained at pH 6 [ 60 ]. Based on the literature data, the presented method of using sodium trithiocarbonate for wastewater treatment is characterized by high efficiency.…”

Ability of Deep Eutectic Solvent Modified Oat Straw for Cu(II), Zn(II), and Se(IV) Ions Removal

“…Numerous different waste materials were investigated as potential biosorbents. Thus, Fan et al used weed as an efficient adsorbent for Cu ion removal [4], while Aguilar et al utilized waste coffee pulp, banana pseudo-stem, and corn cob as potential Zn adsorbents [5]. Previous research revealed that waste biomass as an adsorbent material displays high efficiency due to its large surface area, porosity, low mass, and unique properties.…”