## 1 Introduction  
Dyes, colored compounds, present a serious environmental problem due to the difficulty of treating the contaminated wastewaters by conventional methods. Synthetic dyes have largely supplanted natural dyes, as they offer a wider range of colors and are less expensive to produce [1]. The textile industry discharges wastewater containing toxic dyes, and around 2-20% are directly rejected as liquid effluents into the environment [2]. Most of these dyes are of synthetic origin and toxic in nature, with suspected genotoxic and carcinogenic effects as well as low biodegradability [3, 4]. Crystal violet (CV)--a cationic dye--has been shown to limit photosynthesis in aquatic plants [5]. Removal of CV dye from water by adsorption technique has been widely studied in several previous studies [6, 7]. For example, natural clays collected from different locations in the Albaha region, Saudi Arabia, was proven to have the capability to remove CV via exothermic processes [8].  
In addition, the use of a natural clay mineral with illite and kaolinite functioned as the major component for the removal of methylene blue and CV [6]. The study found that the adsorption of methylene blue and CV to the illicit-kaolinite natural clay can be described by endothermic and exothermic processes, respectively. Therefore, adsorption has been regarded as one of the most efficient treatment methods due to its simplicity, availability, and high efficiency of pollutant separation.  
Today, soils (clays, sands, sediments, etc.) have found widespread utilization as alternative adsorbents in wastewater treatment due to their advantages such as low toxicity, abundant availability, good cation exchange capacity, and important textural proprieties. Dredging operations are defined as the excavation of sediment deposits from the seabed, lake, river, or dams [9]. Currently, a hundred million of these sediments are dredged from underwater each year over the world [10]. Countries in North Africa are very affected by the siltation of dams, which is a complex phenomenon. In Algeria, the average mud deposits volume in reservoir dams is estimated at 20 million m\({}^{3}\) per year [11]. This situation causes a reduction of 0.3% per year in the storage capacity of water [12].  
There are 1150 million m\({}^{3}\) volumes of sediment in the Algerian watersheds, and some dredging operations are thus performed periodically [13]. In recent years, large amounts of sediment have been produced from the dredging activities of Algerian dams. Therefore, it became necessary to search for a strategy for valuing these soils. Dredged sediment from dams (DSD) has complex compositions and is often rich in organic matter, clay minerals, water, and microorganisms, and it frequently contains various organic and inorganic pollutants [14].  
In previous studies, the use of dredged materials from rivers, lakes, and reservoir sediments to construct building materials has been well studied [9; 15; 16; 17]. However, little research has focused on using DSD as an alternative material for the adsorption of pollutants from water media. Therefore, this work's objectives are (1) to investigate the physicochemical, textural and mineralogical characteristics of DSD material from Foum El Gherza dam (Algeria) and (2) to study its application in removing crystal violet (CV) dye from aqueous solutions. Several characteristics of DSD samples have been outlined by using XRD, XRF, FTIR, BET-N\({}_{2}\), and point of zero charge (pH\({}_{\text{PZC}}\)) analysis to learn more about the properties of DSD powder properties. Batch adsorption tests of CV dye were studied by varying pH value (3-11), stirring time (0-300 min), adsorbate concentration (4-250 mg/L), and temperature (20-50 \({}^{\circ}\)C) to explore the sorption behavior (capacity and mechanisms) of CV dye onto DSD adsorbent. The application of different mathematical models to analyze the kinetics and isotherm data was also investigated herein.