ISSN 2071-2227, E-ISSN 2223-2362, Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, 2024, № 1 105 https://doi.org/10.33271/nvngu/2024-1/105 A. Sekhri *1 , orcid.org/0009-0000-5367-9123, L. Mahtout 1 , orcid.org/0009-0005-2664-954X, A. Bouzidi 2 , orcid.org/0000-0002-4616-6896, N. Bouzidi 1 , orcid.org/0000-0002-9154-5895, M. Ferfar 3 , orcid.org/0000-0002-2028-5213 1 ‒ Laboratory of Materials Technology and Process Engi- neering (LTMGP), University of Bejaia, Bejaia, Algeria 2 ‒Electrical Engineering Laboratory (LGE), University of Bejaia, Bejaia, Algeria 3 ‒ Environmental Research Center, Annaba, Algeria * Corresponding author e-mail: abderraouf.sekhri@univ- bejaia.dz ENHANCEMENT OF SORPTION OF THE AZOIC DYE (AZUCRYL RED) BY NATURAL AND CALCINED HYPER-ALUMINOUS KAOLINS Purpose. To remove of basic textile dye Azucryl Red (AR) from aqueous solutions using hyper-aluminous kaolins from Char- ente deposits (France) in natural and calcined states. Methodology. Batch interactive parameter pH, pH pzc contact time, dye concentration, adsorbent loading and temperature are taken to obtain optimums for the AR adsorption process in natural and calcined kaolin named respectively Kca, Kcm, Ckca, and Ckcm. Findings. The adsorption equilibrium was established in 7 min while the second-order kinetic model better described the ad- sorption kinetics for all kaolins with the chemisorption process. The adsorption isotherm of the results obtained corresponds better to the Langmuir model. The maximum quantity retained was 67.97 and 73.38 mg/g respectively for Kcm and Kca samples. More- over, in the calcined state, the maximum quantity retained was 76.66 and 75.64 mg/g respectively for the calcined kaolin CKcm and CKca samples for a temperature of 298 K and pH = 6. The thermodynamic nature of the adsorption process was determined by calculating ΔH, ΔS and ΔG ° values. The positive value of ΔH ° confirms the fact that adsorption is endothermic spontaneous which is enhanced at higher temperatures. Originality. The heat treatments of the different kaolins at 400 °C enhance the adsorption process. Therefore, the results indicate that . Ckcm kcm Ckca kca e e e e q q q q > Ckcm performed with the highest adsorption capacity in the removal of the dye, followed by Ckca. Practical value. Adsorption processes of toxic Azucryl Red dye in the aqueous medium using natural and calcined hyper-alu- minous kaolins at 400 °C were investigated. Optimization and modeling of the adsorption parameters with the theories by Lang- muir, Freundlich and Elovich allowed us to find the optimal experimental conditions for sorption. Our results therefore indicate that the adsorption process of Azucryl red dye from aqueous solutions was enhanced when calcined kaolin at 400 °C containing organic matters was used. Keywords: kaolins, Charente basin, calcination adsorbents, Azucryl red dye, adsorption, environment Introduction. Large amounts of dye wastewater have been produced as a result of the overuse of synthetic dyes in numer- ous sectors. A lot of them are made to be harmful and must be disposed of carefully before being disposed of in the receiving bins. Different kinds of dyes are employed in sectors including the processing of chemicals, and the textile industry. Lotfi, M., et al. [1] claims that to dye 1 kg of cotton with reactive colors, 70 to 150 L of water, 0.6 kg of sodium chloride, and 40 g of reactive dye are normally required. Due to the con- tribution of toxicity, high organic load, and color-related aes- thetic pollution, the effluents containing dyes are very colored and seriously harm the ecosystem and human health during the dyeing and finishing phases, especially with colored prod- ucts where up to 20 to 30 percent of these applied dyes (ap- proximately 2 g/L) are not fixed to the fabric [2]. The majority of synthetic dyes contain aromatic azo groups, which are ex- tremely harmful to the environment because of their muta- genic, carcinogenic, and inert characteristics [3]. Dye physicochemical, optical, and thermal stability as well as resistance to traditional wastewater treatment are all products of the complex aromatic structures [4]. Compared to anionic dyes, cationic dyes are more poisonous [5]. One of the more well- known cationic dyes is Azucryl Red (AR); its structure is depicted in Fig. 1. It is extensively used in paper printing and textile dyeing. Treatment of effluents using the adsorption method has proven to be quite effective by using mass transfer to remove dissolved components [6]. Whereas water recovery is crucial, sorption is used in the textile, leather, dyeing, cosmetics, plas- tics, food, and paper industries [7]. The sorption of organic molecules to an adsorbent de- pends on various physical and chemical factors [8]. The fixing of chromophore groups of dyes such as azo, anthraquinone, triarylmethane, phthalocyanine, formazan, and oxazine, leads to a covalent bond with the fiber, which gives them a good solubility in water, disappearing in the dye. Those dyes resist washing and exhibit good affinity [9]. The general formula of these dyes is represented as ArN + RX - , with R - radical alkyl, X = Cl or, Ar: phenyl radical [10]. ENVIRONMENTAL SAFETY, LABOUR PROTECTION © Sekhri A., Mahtout L., Bouzidi A., Bouzidi N., Ferfar M., 2024