# Commercially Biochar Applied for Tartrazine Removal from Aqueous Solutions
###### Abstract
The feedstock, preparation conditions, and modification approaches affect the properties of biochar and are responsible for their adsorptive performances [14; 24; 25]. The characteristics of the biochar determine the adsorption efficiency. Nonetheless, biochar is thought to be an economical and effective method of eliminating pollutants from water [26]. Testing was performed on the ability of biochar made from different feedstocks to remove various contaminants from aqueous solutions, including organic pollutants and heavy metals [27]. Biochar and biochar-based adsorbents were discovered to be effective in eliminating malachite green [28], crystal violet [28; 29], Congo red [28], remazol black B [30], reactive brilliant blue [31], rhodamine B [31; 32], methylene blue [29; 33], reactive yellow [33], malachite green oxalate [34], safranine T [34], etc. The AR-18 dye removal capability of N-doped biochar made from birch tree wastes has been demonstrated to be superior [35]. [PERSON] et al. prepared sorghum-straw-based biochar that they activated with peroxydisulfate to enhance the tartrazine degradation [36]. To the best of our knowledge, no articles on tartrazine removal from aqueous solutions on biochar have been found in the literature and there are only a few on modified biochar. Thus, biochar-mediated zirconium ferrite nanocomposite [37] and positively charged triethylenettermine biochar [38] were used for the adsorption of tartrazine. However, there are quite a few articles regarding the adsorption of tartrazine on different adsorbents. Activated carbon obtained from coconuts and groundnut shells at 450 \({}^{\circ}\)C and activated with different concentration of hydrochloric acid was an efficient adsorbent for the removal of sunset yellow and tartrazine from aqueous solutions [39]. The effectiveness of the adsorbent obtained from Moringa oleifera seeds was tested for the removal of tartrazine from aqueous solution, obtaining a removal of 95%. The resultswere compared with those obtained for coconut babassu and bone-activated carbon and it was found that the new adsorbent can be an effective alternative to activated carbon [40]. Cellulose obtained from wheat straw residues and cetyltrimethylammonium-chloride-modified cellulose were used for the removal of Congo red and tartrazine from aqueous solution by [PERSON] et al. [41]. Adsorption capacity increased from 2.31 mg g\({}^{-1}\) obtained for the cellulose to 18.85 mg g\({}^{-1}\) for the modified cellulose in the case of tartrazine removal. In the case of the Congo red, the adsorption capacity increased very slightly from 18.5 mg g\({}^{-1}\) for cellulose to 19.92 mg g\({}^{-1}\) for the modified cellulose. [PERSON] et al. tested the activated carbon from apricot stones for tartrazine removal in a batch and dynamic adsorption system. In batch experiments, the maximum adsorption was found to be 76 mg g\({}^{-1}\) at 100 mg L\({}^{-1}\) of tartrazine, while in fixed-bed column experiments, as flow rate increases, the maximum adsorption capabilities decrease [42]. In this paper, commercial biochar was tested for the removal of tartrazine from aqueous solutions, optimizing several parameters (pH, temperature, adsorbent dose, contact time, and initial dye concentration) that influence the adsorption process. To the best of our knowledge, there is no available information about biochar application in tartrazine removal from wastewater. In addition, the commercial biochar selected for the present study is used as fertilizer in agriculture, and its interaction with pollutants is therefore useful knowledge.