Coagulation-flocculation of turbid water using graphene oxide: simulation through response surface methodology and...

Area of Science:

• Environmental Science
• Materials Science
• Water Treatment

Background:

• Turbidity in water poses aesthetic and health concerns.
• Conventional coagulants can have limitations in efficiency and environmental impact.
• Graphene oxide (GO) is explored as a novel, eco-friendly coagulant.

Purpose of the Study:

• To investigate the coagulation properties of graphene oxide (GO) for turbidity removal.
• To determine the optimal conditions for GO-assisted water coagulation.
• To understand the coagulation mechanisms involved.

Main Methods:

• Response Surface Methodology (RSM) was employed to simulate and optimize the coagulation process.
• Key factors investigated included pH, GO dosage, and initial turbidity.
• Analysis of Variance (ANOVA) was used to assess factor significance; Zeta Potential (ZP) and Scanning Electron Microscopy (SEM) analyzed mechanisms and floc formation.

Main Results:

• Optimal turbidity removal efficiency of approximately 98.3% was achieved at pH 3.0, 4.0 mg/L GO dosage, and 193.34 NTU initial turbidity.
• Lowering pH (from 10 to 3) and increasing GO dosage (up to 20 mg/L) significantly enhanced removal efficiency.
• Both sweep flocculation (at basic pH) and electric double-layer compression/ZP reduction (at acidic pH) contributed to coagulation.

Conclusions:

• Graphene oxide demonstrates high potential as an effective coagulant for water turbidity removal.
• RSM successfully identified optimal operating parameters for GO coagulation.
• The layered structure of GO facilitates efficient floc formation and turbidity reduction.