Dopamine-modified Graphene-based Adsorbent for Antibiotics Removal from Aqueous Solutions Yuting Lin, Yan Zhang, Marcia Silva Water Technology Accelerator (WaTA)

Method Figure 1 The polymerization process of dopamine Tetracycline (TC) Ciprofloxacin (CIP) Figure 1 The polymerization process of dopamine Figure 2 The target antibiotics Dopamine: for Graphene-based materials reduction SiO2 & Al2O3 (natural porous materials) PDA: for adhesion Figure 3 The dopamine-modified graphene-based adsorbent

Characteristics Scanning Electron Microscope (SEM) Raman Spectroscopy Surface Figure 4 The SEM images of adsorbent Raman Spectroscopy Figure 5 The Raman image for adsorbent ID/IG=1.15

Results Model Compound Kinetic Model Compound Isotherms The pseudo-second-order model Kinetic study of organic model compound, MB, fit the pseudo- second order model: 𝑡 𝑞 𝑡 = 1 𝑘 2 ∙ 𝑞 𝑒 2 + 1 𝑞 𝑒 𝑡; 𝑞 𝑒 = 1 slope ; 𝑘 2 = slope 2 intercept . 𝑞 𝑒 : Measured values of equilibrium adsorbate concentration in solid phase (mg g-1), 𝑞 𝑡 : Amount of dye absorbed (mg g-1) at time t, t: time (hrs). Isotherms study of organic model compound was studied with different initial compounds concentration, temperature, pH and NaCl ion concentration Figure 7 organic model compound (Methyl Blue, MB) Kinetic for adsorbent Model Compound Isotherms Figure 8 organic model compound (Methyl Blue, MB) Isotherms for adsorbent

Figure 9 The adsorption behavior of CIP Results CIP Adsorption CIP adsorption behavior was studied with contact time and initial compound concentration. TC was also tested but with limited adsorption (~0). Figure 9 The adsorption behavior of CIP

Conclusion The dopamine reduced graphene-based materials was successfully reduced and tightly coated on the surface of porous materials. The Kinetic study for modified adsorbent with MB fits the pseudo-second order model. The isotherms study for modified adsorbent with MB shows the adsorption behavior to equilibrium under different initial concentration, temperature, pH and NaCl concentration. The modified adsorbent’s adsorption behavior of CIP and TC shows the selectivity adsorption properties.

Reference https://pubs.acs.org/doi/10.1021/ma101526k https://scialert.net/fulltextmobile/?doi=rjet.2015.320.331 https://en.wikipedia.org/wiki/Ciprofloxacin https://en.wikipedia.org/wiki/Tetracycline