Removal of Nitro Aromatic Compounds from 2,4,6‐Trinitrotoluene Red Water Using 1,2‐Ethanediamine Modified Macroporous Polystyrene Microspheres

To remove nitro aromatic compounds (NACs) from 2,4,6‐trinitrotoluene (TNT) red water, large‐pore‐size (pore size = 200 nm) polystyrene (PSt) microspheres were activated with chloroacetyl chloride followed by reaction with 1,2‐ethanediamine (EDA). Fourier transform IR analyses showed that the amino group was introduced onto PSt microspheres. Determination of the total amino group and primary amino densities suggested that the imino group was the functional group of EDA–PSt. Scanning electron microscope images and mercury porosimetry measurements indicated that the pore structure was well maintained during the reaction. After adsorption with EDA–PSt, 98.5% chemical oxygen demand and 99% acute toxicity of TNT red water was removed. As shown by HPLC and GC–MS, all the neutral and acid NACs in TNT red water were removed by EDA–PSt, while the basic NACs were not. The results showed that hydrogen bonding and electrostatic attraction were involved in adsorption. The adsorbed neutral and acid NACs were eluted using methanol and 0.1 mol L^?1 NaOH, respectively.     

硅藻土-无定形碳-氧化铁三元复合体系降解三硝基甲苯的研究

煤系共伴生非金属矿产开发及综合利用难度大。本文针对先锋褐煤共伴生硅藻土高有机质、高铁的特点,提出硅藻土原矿经提纯处理后,在N2作为保护气氛下,高温煅烧形成硅藻土-无定形碳-氧化铁三元复合材料,在类Fenton体系下,去除TNT污染物的开发利用技术路线。本文考察了硅藻土处理条件、反应时间、H2O2浓度、三元复合硅藻土投加量、pH值等因素对TNT降解效能的影响。研究表明三元复合硅藻土对TNT吸附降解的最佳工艺条件为:硅藻土用量为2 g/L,H2O2(30%)4 m L/L,pH值1,反应时间2.5 h。该工艺条件下,50 mg/L TNT去除率为98%。     

Differential kinetics and temperature dependence of abiotic and biotic processes controlling the environmental fate of TNT in simulated marine systems

This work seeks to understand how the balance of abiotic and biotic kinetic processes in sediments control the residual concentration of TNT in marine systems after release from ocean-dumped source. Kinetics of TNT disappearance were followed using marine sediments at different temperatures and under both biotic and presumably abiotic conditions (through sodium azide addition). Sediments exhibiting the highest rate of TNT disappearance under biotic conditions also exhibited the highest sorption affinity for TNT under abiotic conditions. Significant temperature dependence in the abiotic processes was observed in the diffusion coefficient of TNT and not sediment sorption affinity. At higher temperature, kinetics of biotic processes outpaced abiotic processes, but at low temperature, kinetics of abiotic processes were much more significant. We concluded that the differential influence of temperature on the kinetics of abiotic and biotic processes could provide distinguishing predictions for the potential residual concentration of TNT contamination in marine-sediment systems.     

2,4,6-Trinitrotoluene in soil and groundwater under a waste lagoon at the former Explosives Factory Maribyrnong (EFM), Victoria, Australia

Energetic materials contamination was investigated at the former Explosives Factory Maribyrnong, Victoria, Australia. Spectrophotometric/high performance liquid chromatography (HPLC) analysis was utilised to delineate a 5 tonne crystalline 2,4,6-trinitrotoluene (TNT) source in a former process waste lagoon that was found to be supplying contaminant leachate to the surficial clay aquitard with a maximum-recorded concentration of 7.0 ppm TNT. Groundwater within underlying sand and gravel aquifers was found to be uncontaminated due to upward hydraulic gradients resulting in slow plume development and propagation. Adsorption and microcosm test results from a parallel study were used as input parameters to simulate aqueous TNT transport in the clay aquitard using ATRANS20 software. The simulated TNT plume was localised within a few metres of the source, and at steady state, though leaching rate calculations suggest that without mitigation or other changes to the system, persistence of the source would be approximately 2,000 years. Remediation strategies may involve removal of the near surface source zone and infilling with an impermeable capping to impede leaching while facilitating ongoing natural attenuation by anaerobic degradation.