漆酶对活性艳蓝染料废水脱色

用白腐真菌漆酶对活性艳蓝X-BR和活性艳蓝K-NR 2种活性染料进行脱色实验。研究了pH、温度、染料浓度和酶活力对脱色率的影响。结果表明,漆酶脱色的适宜条件为:反应温度45℃,pH 6～7,适宜染料浓度为50 mg/L,酶浓度5 U/mL,反应1 h两种染料脱色率可达到75%;通过正交实验确定2种染料的最佳脱色组合分别为:反应温度55℃、pH7、活性艳蓝X-BR浓度50 mg/L、酶浓度5 U/mL和反应温度55℃、pH 6、活性艳蓝K-NR浓度50 mg/L、酶浓度5 U/mL。在所得最优条件下反应1 h,活性艳蓝X-BR和活性艳蓝K-NR的脱色率分别为74.2%和78.6%;反应2 h,脱色率分别为78%和79.5%。     

Selective separation of deltamethrin by molecularly imprinted polymers using a β-cyclodextrin derivative as the functional monomer

A deltamethrin-imprinted polymer (MIP₁) was prepared using bis(-6-O-butanediacid monoester)-β-cyclodextrin (BBA-β-CD) as the functional monomer and toluene 2,4-diisocyanate (TDI) as the cross-linker. In comparison to the molecularly imprinted polymer where β-CD was applied as the functional monomer (MIP₂), MIP₁ showed a higher specific binding capacity (ΔC_P) and an improved imprinting factor (IF) for deltamethrin. The selective recognition experiments demonstrated that compared to MIP₂, MIP₁ could better recognize its template over other substrates that had similar chemical structures. The solid phase extraction (SPE) of deltamethrin using MIP₁ as the adsorbent was further investigated. The recoveries of the molecularly imprinted solid phase extraction (MISPE) column for deltamethrin were 83.2–93.4% with relative standard deviations (RSD) of 2.03–6.19%. The method has been successfully applied to the enrichment of trace deltamethrin from real water samples.     

Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age

Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd) and Al concentrations as well as values of Ca/Al in the tip, middle, base sections and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.     

Leucobacter spp.菌株Ch1还原高浓度Cr(Ⅵ)的研究

利用一株新分离Cr(Ⅵ)还原菌Leucobacter spp. Ch1进行高浓度Cr(Ⅵ)还原的研究.发现生长于Luria Broth培养基中的Leucobacter spp. Ch1最大能还原1800mg/LCr(Ⅵ),而休眠Leucobacter spp. Ch1细胞悬液可以完全还原2100mg/L Cr(Ⅵ).扫描电镜观察到还原cr(Ⅵ)后的细菌末端黏附大团反应产物,电子顺磁共振分析确定产物的成分为Cr(Ⅲ).在分批加Cr(Ⅵ)还原实验中,休眠Leucobacter spp. Ch1细胞悬液在1060min内还原了2368mg/L Cr(Ⅵ),重新加入的乳酸钠可以再次启动Cr(Ⅵ)的生物还原.结果表明,乳酸钠的存在是Leucobacter spp. Ch1还原Cr(Ⅵ)的必要条件,推测该物质在反应中起电子供体的作用.     

Control of metal toxicity, effluent COD and regeneration of gel beads by immobilized sulfate-reducing bacteria

Over the last few decades, the use of sulfate-reducing bacteria (SRB) in the treatment of heavy-metal containing wastewaters including acid mine drainage has become a topic of scientific and commercial interest. However, technical difficulties such as the sensitivity of SRB to toxic metals and high effluent COD limit the widespread use of SRB in high heavy-metal containing wastewater. The aim of this study was to clarify the reasons why the immobilized SRB sludge with inner cohesive carbon source (ISIS) process can endure high metal toxicity and decrease effluent COD. The ISIS process can physically set apart SRB and free the system of external influences such as the surrounding toxic metallic ions, as well as form inner carbon sources to avoid high effluent COD. Metal toxicity and bead durability are the two major factors which influence the regeneration and reuse of gel beads. Reuse of suspended SRB sludge and beads crosslinked with boric acid were unsuccessful due to metal toxicity and agglomeration of beads, respectively. However, beads crosslinked with ammonium sulfate prevented agglomeration of beads allowing successful bead regeneration and reuse. The result of four cyclic trials showed that over 99% of zinc was removed in each trial using these beads.     

Using enriched stable isotope technique to study Cu bioaccumulation and bioavailability in Corbicula fluminea from Taihu Lake,China

In this study, we measured trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) in water and sediment from representative sites of Taihu Lake, with focus on the analysis of trace metal accumulation in Corbicula fluminea (bivalve). The results showed that the quality of water in Taihu Lake was generally good and the correlation was not found between Cu bioaccumulation in C. fluminea and the concentration in water and sediment. Thus, using the stable isotope tracer method, we studied Cu uptake from the water phase, the assimilation of Cu from the food phase, and the efflux of Cu in vivo by C. fluminea. The result revealed that this species exhibited a relatively lower efflux rate constant of Cu compared with other zoobenthos species. Using a simple bioenergetics-based kinetic model, Cu concentrations in the C. fluminea were calculated with the measured efflux rate. We put forward a novel method, which was taking the influence of biological kinetic on metal bioaccumulation into account to explain the field survey data.     

Techno-economic evaluation of biogas upgrading process using CO2 facilitated transport membrane

The biogas upgrading by membrane separation process using a highly efficient CO₂-selective polyvinylamine/polyvinylalcohol (PVAm/PVA) blend membrane was investigated by experimental study and simulation with respect to process design, operation optimization and economic evaluation. This blend membrane takes advantages of the unique CO₂ facilitated transport from PVAm and the robust mechanical properties from PVA, exhibits both high CO₂/CH₄ separation efficiency and very good stability. CO₂ transports through the water swollen membrane matrix in the form of bicarbonate. CO₂/CH₄ selectivity up to 40 and CO₂ permeance up to 0.55 m³(STP)/m² h bar at 2 bar were documented in lab with synthesized biogas (35% CO₂ and 65% CH₄). Membrane performances at varying feed pressures were recorded and used as the simulation basis in this work. The process simulation of an on-farm scale biogas upgrading plant (1000 Nm³/h) was conducted. Processes with four different membrane module configurations with or without recycle were evaluated technically and economically, and the 2-stage in cascade with recycle configuration was proven optimal among the four processes. The sensitivity of the process to various operation parameters was analyzed and the operation conditions were optimized.     

Backward and forward multilevel indicators for identifying key sectors of China’s intersectoral CO2 transfer network

Environmental Science and Pollution Research - Many countries face a dilemma of economic growth and carbon emission mitigation, which is highly associated with energy consumption. In order to...     

Antimony transformation and mobilization from stibnite by an antimonite oxidizing bacterium Bosea sp. AS-1

Soils and waters are heavily contaminated by antimony in Xikuangshan（XKS） mine area.It is widely accepted that oxidative dissolution of sulfide minerals and aqueous dissolution are the most prevalent geochemical mechanisms for the release of Sb to the environment.Bosea sp. AS-1 is an antimonite-oxidizer isolated from the mine slag in Xikuangshan Sb mine. Whole genome sequencing revealed the presence of multiple sulfur-oxidizing genes,antimony（Sb） metabolism genes and carbon fixation genes in AS-...     

Analysis of polycyclic aromatic hydrocarbons in tree-rings of Masson pine (Pinus massoniana L.) from two industrial sites in the Pearl River Delta, south China

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were examined and potential sources of PAHs were identified from the dated tree-rings of Masson pine (Pinus massoniana L.) near two industrial sites (Danshuikeng, DSK and Xiqiaoshan, XQS) in the Pearl River Delta of south China. Total concentrations of PAHs (∑PAHs) were revealed with similar patterns of temporal trends in the tree-rings at both sites, suggesting tree-rings recorded the historical variation in atmospheric PAHs. The differences of individual PAHs and of ∑PAHs detected in the tree-rings between the two sites reflected the historical differences of airborne PAHs. Regional changes in industrial activities might contribute to the site-specific and period-specific patterns of the tree-ring PAHs. The diagnostic PAH ratios of Ant/(Ant + PA), FL/(FL + Pyr), and BaA/(BaA + Chr)) revealed that PAHs in the tree-rings at both sites mainly stemmed from the combustion process (pyrogenic sources). Principal component analysis further confirmed that wood burning, coal combustion, diesel, and gasoline-powered vehicular emissions were the dominant contributors of PAHs sources at DSK, while diesel combustion, gasoline and natural gas combustion, and incomplete coal combustion were responsible for the main origins of PAHs at XQS. Tree-ring analysis of PAHs was indicative of PAHs from a mixture of sources of combustion, thus minimizing the bias of short-term active air sampling.