# Commercially Biochar Applied for Tartrazine Removal from Aqueous Solutions
###### Abstract  
Biochar gained attention due to its definite physico-chemical characteristics and because it is a cost-effective and efficient adsorbent. In this paper, commercial biochar was tested for the removal of tartrazine from aqueous solutions. Thus, the optimum experimental conditions were determined for several parameters (pH, temperature, initial concentration of tartrazine, biochar dose, and contact time). The concentration of tartrazine residues was determined using UV-Vis spectrophotometry. The best experimental results were obtained at 1 mg L\({}^{-1}\) concentration of tartrazine, pH 2, 30 \({}^{\circ}\)C, 18 min, and 0.9 g L\({}^{-1}\) adsorbent dose. The maximum removal efficiency of tartrazine obtained in optimum conditions was 90.18%. The experimental data were analyzed by the isotherm and kinetic models. The isotherm and kinetics of tartrazine removal on biochar follow the Langmuir isotherm and pseudo-second-order kinetics, respectively. According to the Langmuir isotherm model, the biochar showed a maximum adsorption capacity of 3.28 mg g\({}^{-1}\). In addition, biochar demonstrated a good reuse potential and therefore can be used for the removal of tartrazine from aqueous solutions. biochar; adsorption; tartrazine; isotherm; kinetic studies +
Footnote †: journal:  
0000-0002-2300-3300][PERSON]  
0000-0002-0002-3300][PERSON]  
0000-0002-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-3300-33000-3300-3300-33  
studies. Due to these concerns regarding its toxicity and side effects, tartrazine is already banned in some countries. In 1959, [PERSON] described for the first time tartrazine-induced urticaria [5]. Since then, many other studies were performed in order to elucidate the risks associated with tartrazine consumption. While the studies of [PERSON] et al. and [PERSON], from 1987 and 1988, respectively, show that there is no carcinogenic effect from the use of tartrazine, in a study from 2002, [PERSON] et al. claim that it may induce DNA damage in mice colon [6; 7; 8; 9]. Although the severity of the side effects of the tartrazine are still under debate, it is clear that limiting its spread and contact with human and living cells will also prevent or minimize the unwanted consequences that it might generate. For this reason, providing low-cost, efficient methods for their removal from the environment could be considered as an achievement. Effective ways to treat polluted effluents are required since tartrazine's chemical treatment produces harmful chemicals and its breakdown is difficult due to the aromatic rings on both sides of the azo group [4]. Many conventional physical and biological methods were employed for the removal of dyes from water--among these, photodegradation, coagulation, membrane separation, reverse osmosis electrochemical processes, and adsorption [10; 11; 12; 13]. Most of these processes require high operational and capital costs, which restricts their application for the removal of contaminants from polluted waters [14]. Adsorption has become one of the most used processes due to its modest costs, simple operating conditions, high flexibility, material regeneration, and environmental friendliness [15; 16]. Many adsorbents are frequently used to remove dyes from contaminated water. The benefits of metal-oxide-based, bio-adsorbent, metal-organic framework, polymer-based, and activated-carbon materials include ease of production, high surface area, high reactivity, reusability, cheap cost, and high efficiency [17; 18; 19; 20; 21; 22; 23]. Recent research has used biochar and biochar-based adsorbents to remove pollutants from aqueous media because biosorbents are desired for environmental remediation. This can be used in both batch and continuous flow systems and it can be used in combination with other adsorbents to enhance its adsorption capacity [24].