Xuecheng Sun,Yong Sun,Shuguang Lyu,Zhaofu Qiu,Qian Sui
In this study, nano-CaO 2 (nCaO 2 ) was successfully synthesized and constituted the nCaO 2 /Fe(II) system applying to remediate BTEX, which are typical mixed pollutants in contaminated groundwater. The particle size of the synthesized nCaO 2 was 108.91 nm, and it displayed better BTEX remediation performance than that of commercial CaO 2 . The innovative generation pattern of hydroxyl radicals ( ) in the nCaO 2 /Fe(II) system has been investigated using benzoic acid as the probe, and the proper molar ratio of nCaO 2 /Fe(II) was optimized as 1/1. Over 90% of BTEX was removed in 180 min with the nCaO 2 /Fe(II)/BTEX molar ratio of 40/40/1. Further experiments evaluated the influence of co-existence of mixed pollutants chlorinated hydrocarbon compounds (CHCs) or surfactant constituents on BTEX remediation performance. The experimental results suggested that CHCs have limited influence on BTEX removal rate and surfactants have negative effects on BTEX remediation performance in the experimental conditions. In conclusion, the findings in this study could give some inspirations to apply the nCaO 2 /Fe(II) process in remediating co-existing pollutants in contaminated groundwater. Practitioner points nCaO 2 /Fe(II) system applied to remediate mixed contaminants. generation pattern of the nCaO 2 /Fe(II) system has been investigated. The influence of chloride hydrocarbon compounds have been studied. The effects of surfactants were evaluated.
Li-Hui Chen,Xing-Yi Chen,Shuang Song,Shui-Feng Zhang,Yong-Gang Zhao,Yin Lu
Magnetic polymer microspheres have been extensively utilized as separable and highly efficient adsorbents in wastewater treatment. In this study, a series of novel magnetic spongy porous carbon skeleton materials (Mag-SPCS) have been designed and synthesized by acetonitrile suspension precipitation polymerization, which combines the advantages of the acetonitrile precipitation method and the suspension polymerization method. It was demonstrated that the transformation of the material morphology from microspheres to a porous sponge was achieved by a gradual decrease in the usage amount of ethylene glycol. After N,N-dimethyloctadecylamine (C18) was grafted onto the Mag-SPCS materials, the C18-Mag-SPCS materials with a superhigh saturation adsorption capacity and superfast adsorption efficiency were used for the removal of BTEX (toluene, benzene, and para-xylene) in wastewater. Subsequently, the adsorption properties of the composites with different morphologies were evaluated, and the effect of the usage amount of C18 on the adsorption properties of the C18-Mag-SPCS was further investigated. The maximum adsorption capacities of C18-Mag-SPCS for benzene, toluene, and para-xylene were 714.84, 564.32, and 394.48 mg/g, respectively. The adsorption process was conducted in accordance with the proposed secondary and Langmuir models. Finally, the FTIR, XPS, and XRD characterization results before and after adsorption demonstrated that the adsorption mechanism of toluene onto C18-Mag-SPCS was primarily hydrogen bonding, π–π stacking, and van der Waals forces. These findings of the study indicate that the composite material exhibits an ultrahigh saturation adsorption capacity and ultrafast adsorption efficiency, thereby confirming its considerable potential for application in wastewater treatment.
The performance of trichloroethene (TCE) degradation was significantly improved with the addition of FeS in nanoscale calcium peroxide (nCP) environment and the enhancement of HO generation in nCP/Fe(II)/FeS system was confirmed by comparison with nCP/Fe(II) and nCP/FeS systems. The role of FeS in nCP/Fe(II)/FeS system demonstrated that the majority of reactive oxygen radicals (ROSs) was generated on the catalyst surface due to the heterogeneous reaction through FeS activated nCP in one hand, and the reductive FeS could promote TCE degradation by regenerating Fe(II) from Fe(III) in the other hand. The probe as well as scavenger test results suggested that the major ROSs was HO rather than O 2 − . Over 91.5% TCE could be degraded at the molar ratio of 2/2/4/1 of nCP/Fe(II)/FeS/TCE, in which more than 95.5% TCE was dechlorinated. The effect of surfactants on TCE degradation was evaluated. In contrast, further investigation found that BTEX removal was inhibited with the addition of FeS. In conclusion, this study revealed the well function and fundamental synergistic mechanism of FeS. Moreover, the degradation of TCE in actual groundwater confirmed that nCP/Fe(II)/FeS technique has a great advantage and potential in TCE contaminated groundwater remediation in ISCO practice.
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