石墨相氮化碳负载尖晶石型铁钴硫化物活化过氧乙酸降解自然水体中罗丹明B的研究

Degradation of Rhodamine B in NaturalWaters by Peracetic Acid Activated with FeCo_(2)S_(4) Modified g-C_(3)N_(4)

通过水热法合成了一种新型氮化碳负载尖晶石型铁钴硫化物(FeCo_(2)S_(4)-CN),并将其用于活化过氧乙酸(PAA)降解罗丹明B(RhB),考察了初始pH和常见水体组分对FeCo_(2)S_(4)-CN/PAA体系降解RhB的影响,在此基础上研究了该体系对两种自然水体中RhB的降解效能和机理,论证该技术实际应用的可行性。结果表明,近中性条件(pH=6.5)最有利于FeCo_(2)S_(4)-CN/PAA体系降解RhB。SO_(4)^(2-)、NO_(3)^(-)、Ca^(2+)、Mg^(2+)以及低浓度Cl-与富里酸(FA)几乎不影响RhB的降解;而HCO_(3)^(-)、高浓度的Cl-与FA能够竞争FeCo_(2)S_(4)-CN/PAA体系产生的活性自由基,从而抑制RhB的降解。自然水体组分中的HCO_(3)^(-)、FA以及其他还原性物质虽然能够通过淬灭自由基削弱FeCo_(2)S_(4)-CN/PAA体系的氧化性能,但是FeCo_(2)S_(4)-CN/PAA体系展现出较强的抗干扰能力,仍能够实现对目标污染物的有效降解。自然水体组分不会影响FeCo_(2)S_(4)-CN/PAA体系降解RhB的机理(即活性自由基对RhB发色基团的破坏),它们主要通过自由基清除影响体系的氧化性能。

In this study,a novel Fe/Co bimetallic spinel sulfide modified g-C_(3)N_(4) composite(FeCo_(2)S_(4)-CN)was synthesized via a hydrothermal procedure and applied to activate peracetic acid(PAA)for degradation of rhodamine B(RhB).The effect of initial pH and common water matrix on the degradation of RhB in the FeCo_(2)S_(4)-CN/PAA system was investigated.The degradation efficiency and mechanism of RhB in two natural water under the FeCo_(2)S_(4)-CN/PAA system were further studied,and the feasibility of the FeCo_(2)S_(4)-CN/PAA system in the practical application was demonstrated.Near-neutral condition(pH=6.5)was the most favorable for the removal of RhB in the FeCo_(2)S_(4)-CN/PAA system.The SO_(4)2-,NO3-,Ca^(2+),Mg^(2+)and low concentrations of Cl-and fulvic acid(FA)had little effect on the removal of RhB in the FeCo_(2)S_(4)-CN/PAA system.However,the HCO3-,high concentrations of Cl-and FA could inhibit RhB removal by competing with reactive radicals.Although HCO3-,FA,and other reductive species in natural waters could inhibit the oxidation capacity of the FeCo_(2)S_(4)-CN/PAA system by reactive radicals scavenging,FeCo_(2)S_(4)-CN/PAA system exhibited a strong capacity of resisting disturbance and achieved a satisfactory degradation efficiency of the target contaminant.The degradation mechanism of RhB in the FeCo_(2)S_(4)-CN/PAA system(i.e.,the destruction of chromophores in RhB by the attack of active radicals)would not be affected by the composition of natural waters,while the oxidation capacity of FeCo_(2)S_(4)-CN/PAA system could be inhibited via reactive radicals scavenging by water matrixes.