Crystal violet removal using algae-based activated carbon and its composites with bimetallic Fe⁰-Cu

Abstract

Abstract The textile industry is considered a source of pollution because of the discharge of dye wastewater. The dye wastewater effluent has a significant impact on the aquatic environment. According to the World Bank, textile dyeing, and treatment contribute 17 to 20% of the pollution of water. This paper aims to prepare the bimetallic nano zero-valent iron-copper (Fe 0 -Cu), algae-activated carbon, and their composites (AC-Fe 0 -Cu), which are employed as adsorbents. In this paper, Synthetic adsorbents are prepared and examined for the adsorption and removal of soluble cationic crystal violet (CV) dye. The influence of synthetic adsorbents on the adsorption and removal of soluble cationic crystal violet (CV) dye is investigated using UV-V spectroscopy at different pH (3–10), time intervals (15–180) min, and initial dye concentrations (50–500 ppm). Raw algae exhibit an impressive 96.64% removal efficiency under the following conditions: pH 7, contact time of 180 min, rotational speed of 120 rpm, temperature range of 25 °C–30 °C, concentration of 300 ppm in the CV dye solution, and a dose of 4 g l −1 of raw algae adsorbent. The best removal efficiencies of Raw algae Fe 0 -Cu, and H 3 PO 4 chemical AC-Fe 0 -Cu are 97.61 % and 97.46 %, respectively, at pH = 7, contact time = 150 min, rotational speed = 120 rpm, T = (25–30) °C, concentration = 75 ppm of CV dye solution, and 1.5 g l −1 doses of raw algae F e0-Cu adsorbent and 1 g l −1 dose of H 3 PO 4 chemical AC-Fe 0 -Cu adsorbent. The maximum amounts ( q max ) of Bi-RA and RA adsorbed for the adsorption process of CV are 85.92 mg g −1 and 1388 mg g −1 , respectively. The Bi-H 3 A-AC model, optimized using PSO, demonstrates superior performance, with the highest adsorption capacity estimated at 83.51 mg g −1 . However, the Langmuir model predicts a maximum adsorption capacity ( q e ) of 275.6 mg g −1 for the CV adsorption process when utilizing Bi-H 3 A-AC. Kinetic and isothermal models are used to fit the data of time and concentration experiments. DLS, zeta potential, FT-IR, XRD, and SEM are used to characterize the prepared materials. Response surface methodology (RSM) is used to model the removal efficiency and then turned into a numerical optimization approach to determine the ideal conditions for improving removal efficiency. An artificial neural network (ANN) is also used to model the removal efficiency.