超声和H2O2对双酚A模拟废水的毒性源头消减

对含双酚A模拟废水处理的序列间歇式活性污泥法(SBR)活性污泥系统,进行分别以超声破碎和投加H2O2氧化两种模式的污泥源头处理。分别以发光菌表征的微生物毒性和种子发芽率表征的植物毒性来衡量污泥毒性,通过对照污泥经源头处理前后的水相指标变化和以酶活性表征的污泥特性变化,考察污泥源头处理模式对污泥毒性消减效果和对污泥特性的影响。结果表明,污泥经源头处理后超声组污泥毒性最大,而H2O2组污泥毒性最小,空白组污泥毒性居中。种子发芽率表征的植物毒性与发光菌表征的微生物毒性成正相关关系。污泥经超声和H2O2源头处理后的脱氢酶活性和过氧化氢酶活性的变化趋势与污泥毒性显著相关。     

A novel application of H2O2-Fe(II) process for arsenate removal from synthetic acid mine drainage (AMD) water

Batch experiments were carried out to investigate the influences of H₂O₂/Fe(II) molar ratio, pH, sequence of pH adjustment, initial As(V) concentration, and interfering ions on As(V) removal in H₂O₂-Fe(II) process from synthetic acid mine drainage (AMD). The optimum H₂O₂/Fe(II) molar ratio was one for arsenate removal over the pH range of 4-7. Arsenate removal at pH 3 was poor even at high Fe(II) dosage due to the high solubility of Fe(III) formed in situ. With the increase of Fe(II) dosage, arsenate removal increased progressively before a plateau was reached at pH 5 as arsenate concentration varied from 0.05 to 2.0 mg L⁻¹. However, arsenate removal was negligible at Fe/As molar ratio <3 and then experienced a striking increase before a plateau was reached at pH 7 and arsenate concentration ≥1.0 mg L⁻¹. The co-occurring ions exerted no significant effect on arsenate removal at pH 5. The experimental results with synthetic AMD revealed that this method is highly selective for arsenate removal and the co-occurring ions either improved arsenate removal or slightly depressed arsenate removal at pH 5-7. The extended X-ray absorption fine structure (EXAFS) derived As-Fe length, 3.27-3.30 Å, indicated that arsenate was removed by forming bidentate-binuclear complexes with FeO(OH) octahydra. The economic analysis revealed that the cost of the H₂O₂-Fe(II) process was only 17-32% of that of conventional Fe(III) coagulation process to achieve arsenate concentration below 10 μg L⁻¹ in treated solution. The results suggested that the H₂O₂-Fe(II) process is an efficient, economical, selective and practical method for arsenate removal from AMD.     

Performance evaluation and application of surface-molecular-imprinted polymer-modified TiO2 nanotubes for the removal of estrogenic chemicals from secondary effluents

The removal of estrogenic chemicals during wastewater reclamation has been a great concern. Current advanced treatment processes are inefficient for the removal of estrogenic chemicals from secondary effluents of municipal wastewater treatment plants (WWTPs) due to the coexistence of other pollutants with less environmental significance which are also removed simultaneously. The search for highly selective and low-cost removal methods is warranted. Therefore, surface-molecular-imprinted polymer-modified TiO₂ nanotube (S-MIP-TiO₂ NT) photocatalysts were fabricated, characterized, and tested for the removal of estrogenic pollutants from wastewater in this study for the first time. Scanning electron microscopy and Fourier-transform infrared spectroscopy studies showed that the TiO₂ NTs (with an average diameter of 60 nm) were successfully imprinted with functional groups (i.e., carboxyl). The adsorption selectivity and photocatalytic activity of the S-MIP-TiO₂ NTs towards template compound (17β-estradiol, E2) were improved, compared with neat TiO₂ NTs. Interestingly, S-MIP-TiO₂ NTs exhibited higher adsorption intensity and photocatalytic selectivity at low concentrations (from 10 ng/L to 100 μg/L, as normal estrogenic chemical concentrations in secondary effluents) of E2 than that at high concentrations (from 10 to 1,000 mg/L). It was also found that some representative estrogenic chemicals and estrogenic activity could be selectively and rapidly removed from secondary effluents of municipal wastewater treatment plants using S-MIP-TiO₂ NTs as photocatalysts. In addition, S-MIP-TiO₂ NT photocatalysts exhibited excellent regeneration characteristics. Photocatalytic treatment using S-MIP-TiO₂ NTs could be a promising approach for the effective removal of estrogenic chemicals from secondary effluents of municipal WWTPs.     

A novel nano-sized Co3O4@C catalyst derived from Co-MOF template for efficient Hg0 removal at low temperatures with outstanding SO2 resistance

Environmental Science and Pollution Research - Co3O4 is a promising Hg0 removal catalyst for industrial application. Operating temperature and low sulfur resistance are two of the main problems...