Low Cost Modified Biochars from Peanut Shells for the Removal of Textile Dyes

Abstract

Biochars from peanut shell wastes were produced and further modified with KOH and HNO3 to efficiently remove two industrial dyes, Mordant Orange 1 and Green Malachite oxalate, in aqueous systems. The materials were characterized through elemental analysis, N2 adsorption isotherms, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and the determination of the point of zero charge, pHPZC. The basic and, particularly, the acid treatments increased the specific surface area by 15 and 43%, respectively, and the pHPZC shifted from 6.2 to 9.1 or 3.3 upon treatments with KOH or HNO3. These modifications impacted the adsorption behavior of the dyes; in the case of Mordant Orange 1, the adsorption capacity increased 2 and 4 times, respectively, when compared with the parent biochar. These results show that the performance of biochars can improve substantially through simple modifications using acid or basic treatments that not only increase the specific surface area but also modify adsorbent/adsorbate interactions.

Synthesis of materials from agricultural wastes combined with Fe3O4 for methylene blue adsorption and application to treat organic pollutants in water samples

“…This research aims to achieve at least two objectives: first, to create potential adsorbent materials for organic dye adsorption from lowcost agricultural waste available in nature, and second, to contribute to reducing environmental pollution caused by these waste products. Currently, many studies have been published on the use of agricultural waste as a precursor for synthesizing adsorbent materials for organic dyes adsorption, such as orange peels, 2,3 grapefruit peel, [4][5][6][7] coffee grounds, [8][9][10] banana peels, [11][12][13][14][15] corn waste, [16][17][18][19][20] peanut shells, [21][22][23] durian waste, [24][25][26][27] dragon fruit peels, [28][29][30] etc. Dragon fruit peels have been attracting attention for synthesizing adsorbent materials for organic dyes adsorption due to the presence of compounds such as phenolic compounds, betalains, betacyanins, and other functional groups like C═C, C═O, OH, and NH.…”