Abstract
In this work, charcoal-type adsorbents were prepared from black liquor, a cellulose and paper industry residue rich in lignin and containing inorganic salts. During the preparation of adsorbent materials, black liquor was dried at 120 °C and then pyrolyzed at different temperatures (600 °C, 700 °C, and 800 °C) under a nitrogen atmosphere. The samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), measurement of specific surface area (BET), point of zero charges (PZC) determination, and evaluating of removal capacity of methylene blue dye. DRX results indicated the presence of crystalline phases of different salts, mainly sodium carbonate, on the surface of the produced carbonaceous materials from black liquor waste. Besides, a significant effect of the pyrolysis temperature on the charcoal crystallinity was observed. Materials presented low values of porosity and specific surface area, and similar morphologies. Solids' surface character was predominantly alkaline, according to PZC curves. All solids were efficient in removing 70 to 85% of the methylene blue's color.
Highlights
Anthropogenic activities for the exploitation of natural resources have been increasingly damaging the environment, so that it is necessary to develop research in the environmental area
Considering that solids had prepared from the same sample of black liquor and, have the same elemental composition, the distinguished profiles observed can be related to phase changes
Based on chemical composition, determined by energy-dispersive spectroscopy (EDS) (Table 1), knowledge of black liquor nominal composition, and search carried out in the Match software database, it was possible to identify the presence of the following phases: sodium carbonate (ICSD 96-101-1296), sodium sulfate (ICSD 96-210-2307), potassium carbonate (ICSD 96-900-9645), calcium oxide (ICSD 96-900-6708), and orthorhombic calcium carbonate (ICSD 96- 721-0492) and trigonal (ICSD 96-900-0971)
Summary
Anthropogenic activities for the exploitation of natural resources have been increasingly damaging the environment, so that it is necessary to develop research in the environmental area. The industry is responsible for a large part of water consumption and to produce highly contaminated effluents. It led to the development of various wastewater treatment technologies. Could highlight the advanced oxidation processes (AOP), which consist of degrading stable toxic organic compounds, such as phenols and some dyes [1, 2]. M. Oliveira et al, Scientia Plena 16(12), 124201 (2020)
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