| Surfactants are capable of changing interfacial properties between particles and contaminants,and consequently affect the adsorption and catalytic property of materials.Cetyltrimethyl ammonium bromide?CTAB?was innovatively introduced into simulated Orange ? wastewater,and adsorption and sonocatalytic degradation performance of bagasse biochar were systematically studied in this research.The research results are presented as following:?1?During the adsorption process,an increase in CTAB concentration significantly enhanced the removal of Orange ? by bagasse biochar.With the increase of bagasse biochar dosage,the removal efficiency for Orange ? increased,while the adsorption capacity decreased as a result of the increase of active adsorption sites on bagasse biochar surface.The adsorption capacity for Orange ? increased from 1.66 mg/g in the absence of CTAB to 4.42 mg/g in the presence of 2.0 mg/L of CTAB.Pseudo-first-order and pseudo-second-order kinetic models can be used to describe experimental data,while linear pseudo-second-order kinetic models can better fit experimental data at pH 5.0,7.0 and 9.0,whether CTAB were introduced or not.In the presence of CTAB,the adsorption isotherm curve for Orange ? was almost linear,which was quite different from that in the absence of CTAB.It can be inferred that the existence of CTAB changes the charge properties of the biochar surface,and the electrostatic attraction played a predominant role for the removal of Orange ? by bagasse biochar.?2?For the sonocatalytic degradation of Orange ?,an increase in the dose of CTAB and bagasse biochar can significantly improve the sonocatalytic degradation of Orange ?.When the dose of CTAB was 0 and 2.0 mg/L,the Kapp values for the sonocatalytic process were3.73×10-3 and 8.55×10-3 min-1,respectively.In the presence of CTAB,the efficiency of sonocatalytic degradation of Orange ? decreased with increasing solution pH,and the inorganic salt ions weakly inhibited the degradation.An increase of ultrasonic power was beneficial to the degradation of Orange ?.At the same time,in the presence of CTAB,a significant synergetic effect was observed between the bagasse biochar adsorption and ultrasonication.The quenching experiments by isopropanol and KBr demonstrated that the free radical chain reaction mainly occurred in the interface region during the sonocatalytic degradation process,while the occurrence in the bulk solution was insignificant.The test on the contribution of OHˇfree radicals indicated that OHˇfree radicals still played a predominant role in the overall reaction.The above proved that the surfactant CTAB had a significant enhancement effect on the adsorption and sonocatalytic degradation process,which demonstrates a promising practical application values. |
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