Biochar Derived from Water Hyacinth Biomass Chemically Activated for Dye Removal in Aqueous Solution

Rapid industrial development has led to the use of numerous dyes responsible for significant water pollution worldwide. Adsorbents have been developed to treat these waters, mainly in the form of activated biochar, which has several advantages, one of which is its good surface characteristics, such as high surface area and pore volume. The objective of the investigation was to analyze the efficiency of removing the methylene blue model dye in aqueous solutions through the adsorption process using biochar chemically activated from the leaf and stem of water hyacinth (Eichhornio crassipes) as a bioadsorbent. This study carbonized the stem and leaf containing zinc chloride at 600 °C. The materials were characterized by different techniques and were tested for their ability to adsorb methylene blue. The activated stem and leaf biochars removed approximately 285.71 and 322.58 mg g−1 of the dye, respectively, indicating that the adsorption is more significant in the leaf. Pseudo-second-order kinetics was the most suitable model to describe dye adsorption on biochars, and the experimental isotherm data fit the Langmuir model. It is concluded that the application of activated water hyacinth biochar is a renewable resource with the potential for effluent treatmentCoordination Support in Higher Education (CAPES) UFPI-IFPI 45-2018National Council for Scientific and Technological Development (CNPq) UFPI-IFPI 45-2018Foundation of Support to Research of Piauí (FAPEPI) UFPI-IFPI 45-201

Using Activated Biochar from <i>Caryocar brasiliense</i> Pequi Almonds for Removing Methylene Blue Dye in an Aqueous Solution

Water pollution remains a global problem that urges researchers to develop new technologies aimed at environmental restoration. Here, this study aimed at obtaining an activated biochar from pequi almonds for dye removal. Before and after adsorption, the materials underwent characterization using techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy, and thermogravimetric analysis (TG). The biochar from the pequi almond was called BA, and the activated biochar from the pequi almond was called ABA. The influence of the pH, contact time, and adsorbate concentration on adsorption was investigated using the dye methylene blue. The morphological assessment revealed higher cracks and pores in the ABA than in the BA. The TG showed that the BA lost approximately 19% more mass than the ABA, indicating that activation occurred. The activation contributed to the decrease in the degree of disorder in the BA because of the increased number of graphitic carbon atoms (ordered) in the ABA, as observed via Raman. The adsorption kinetics followed a pseudo-second-order model, while the adsorption isotherms followed the Langmuir model. The BA adsorption capacity was 500.00 mg g−1, constituting a robust solution for dye removal from aqueous environments. Therefore, this implies the success of the process