A stable Fe/Co bimetallic modified biochar for ofloxacin removal from water: adsorption behavior and mechanisms

Abstract

Fe/Co bimetallic modified biochar (FMBC) was synthesized and characterized, and its adsorption mechanism of ofloxacin and the stability of FMBC were investigated.

Calcined Bean Dregs-Hydrocalumite Composites as Efficient Adsorbents for the Removal of Ofloxacin

“…At pH < 5, electrostatic repulsion occurs between the positively charged surface of the composite and OFL + in solution, and at pH > 5, electrostatic repulsion also occurs between the negatively charged surface of the composite and the OFL – in solution. 19 , 38 In summary, electrostatic attraction is not the main adsorption mechanism of 70% BD-CaAl-LDH600 on ofloxacin, and the pH value of the solution is not a key factor affecting the adsorption performance of 70% BD-CaAl-LDH600 against ofloxacin. 39 …”

“…In addition, the theoretical adsorption capacity ( Q e ) obtained by the pseudo-second order dynamic model was closer to the experimental adsorption capacity ( Q exp ). The results showed that the adsorption process of 70% BD-CaAl-LDH600 on ofloxacin conformed to the pseudo-second-order dynamic model, which was consistent with the kinetic behavior of adsorption reported by Hao et al…”

“…When pH < 5.98, ofloxacin is mainly in the form of cations (OFL + ); when pH > 8.00, it is mainly in the form of anions (OFL – ); when it is 5.98, it mainly exists in the form of zwitterion. , The zeta potential of 70% BD-CaAl-LDH600 at different pH values is shown in Figure b. At pH < 5, electrostatic repulsion occurs between the positively charged surface of the composite and OFL + in solution, and at pH > 5, electrostatic repulsion also occurs between the negatively charged surface of the composite and the OFL – in solution. , In summary, electrostatic attraction is not the main adsorption mechanism of 70% BD-CaAl-LDH600 on ofloxacin, and the pH value of the solution is not a key factor affecting the adsorption performance of 70% BD-CaAl-LDH600 against ofloxacin …”

“…As the results shown in Figure 9 , the peaks at 3412, 2926 cm –1 /2925 cm –1 /2857 cm –1 /2858 cm –1 , 1431 cm –1 /1435 cm –1 , and 1058 cm –1 /1069 cm –1 are the telescopic vibrations of −OH, −C–H, −C=C–O, and–C–O, respectively. 38 , 46 The peaks around 873 and 712 cm –1 are caused by the vibration of calcium aluminum oxide. 25 , 47 After adsorption, the peak at 1799 cm –1 was added compared with before adsorption, where the peak is the characteristic peak of −C=O, 46 representing that the ofloxacin is adsorbed on the surface of the composite.…”

“…At pH < 5, electrostatic repulsion occurs between the positively charged surface of the composite and OFL + in solution, and at pH > 5, electrostatic repulsion also occurs between the negatively charged surface of the composite and the OFL − in solution. 19,38 In summary, electrostatic attraction is not the main adsorption mechanism of 70% BD-CaAl-LDH600 on ofloxacin, and the pH value of the solution is not a key factor affecting the adsorption performance of 70% BD-CaAl-LDH600 against ofloxacin. 39 Using 70% BD-CaAl-LDH600 as adsorbent, the effect of adsorbent dosage on the adsorption performance of ofloxacin was investigated under the conditions of initial concentration of ofloxacin of 20 mg•L −1 , 30 °C, and 2 h, and the results were shown in Figure 6c.…”