Design and development of a high-performance 3D graphene system for adsorptive removal of organic toxins from wastewater: Mechanisms and process optimization

Abstract

Degradation of water quality caused by organic dyes discharge is a great concern owing to their high toxicity and bioaccumulative nature. A new three-dimensional cellulose/titanium/graphene oxide (3D-CTG) system was fabricated via an ecofriendly ice-segregation method for sequestrating malachite green (MG) and crystal violet (CV) dyes in polluted water. The designed graphene oxide-based system was validated by several analytical techniques, with the results indicating the formation of lamellar porous networks and abundant chemical functional groups. The adsorption of the dyes was modeled by response surface methodology whereby 4 parameters (dosage, initial concentration, temperature and contact time) were optimized to achieve the highest CV removal (94.29%) at 10 mg of adsorbent dosage, 70 mg/L of initial CV concentration, 30 °C and 45 min, and the highest MG removal (81.07%) at 12.5 mg of dosage, 40 mg/L of initial MG concentration, 40 °C and 31 min. The saturated 3D-CTG adsorbent was recyclable as supported by 41.1 – 71.7% regeneration efficiencies after the fourth cycle of usage. The Langmuir maximum adsorption capacities of CV (583.6 mg/g) and MG (334.8 mg/g) dyes were comparable to the literature data which reflected the superior adsorption performance and high applicability of the new 3D-CTG system in the decontamination of organic dyes wastewater.