One-pot eco-friendly synthesis of edge-carboxylate graphene via dry ball milling for enhanced removal of acid and basic dyes from single or mixed aqueous solution

Abstract Effluent water of industrial dyes has been a persistently taxing issue. However, the influential coexistent removal of different charge dye ions remains as a challenge. Herein, a one-plot eco-friendly route was developed to prepare flake-like graphite-derived edge-carboxylate graphene via dry ball milling at time intervals of 4 and 8 h for the simultaneous removal of oppositely charged dye ions. The prepared edge-carboxylate graphene (ECG4h and ECG8h) was confirmed using various analytical methods. Then, the Brunauer–Emmett–Teller surface area and total pore volume exhibited ECG8h, ECG4h and graphite value of 387.69, 316.47, 7.84 m2 g-1, and 0.55, 0.46, 0.03 cm3 g-1. ECG4h and ECG8h particle size distribution were analysed by DLS techniques. Zeta potential with various pH effects of ECG4h and ECG8h surface charge was used to determine the key role of dye adsorbent and desorption conditions. These experiments were performed under various pH values (acidic: 4.0 ± 0.2, neutral: 7.0 ± 0.2, basic: 10.0 ± 0.2). Results show that the prepared adsorbent can clean dye-contaminated water by more than 99.7% ± 0.2% within 5–20 min. The broad potential application indicates the performed filtration studies for the above-mentioned dyes using ECG8h of up to five cycles. As-prepared ECG8h material exhibits numerous advantages, including time-consuming, cost-effective and energy-efficient robust removal of dyes.