Application of Advanced Ceratophyllum demersum Activated Carbon in Toxic Dye Adsorption: Optimization via Box-Behnken...

Water contamination by cationic dyes such as crystal violet (CV) is a significant environmental concern due to their toxicity and persistence. This study investigated and optimized CV adsorption onto Ceratophyllum demersum activated carbon (CDAC) using the Box-Behnken design (BBD) and artificial neural network (ANN) models. CDAC exhibited a specific surface area of 190.56 m² g^-1 and a mesoporous structure containing oxygen- and phosphorus-bearing functional groups. Batch adsorption experiments showed adsorption capacities ranging from 95 to 290 mg g^-1, with adsorption following pseudo-second-order kinetics and exhibiting favorable isotherm behavior. Although the ANN model produced lower prediction errors (≤ 8%) than the BBD model (≥ 20%), the BBD model was considered more reliable given the limited experimental dataset. Optimization predicted a maximum adsorption capacity of 258.76 mg g^-1 and a removal efficiency of 86% at an initial CV concentration of 150 mg L^-1, a CDAC dose of 0.5 g L^-1, and a contact time of 10 min. Germination assays using Lens culinaris seeds indicated reduced phytotoxicity after treatment. These results demonstrate that CDAC is an effective and sustainable adsorbent for CV removal from aqueous solutions.