Preparation of various thiol-functionalized carbon-based materials for enhanced removal of mercury from aqueous solution

In this work, biochar (BC), activated carbon (AC), and graphene oxide (GO) were thiol-functionalized using 3-mercaptopropyltrimethoxysilane (3-MPTS) (named as BCS, ACS, and GOS, respectively). BCS, ACS, and GOS were synthesized mainly via the interaction between hydrolyzed 3-MPTS and surface oxygen-containing functional groups (e.g., –OH, O–C=O, and C=O) and π-π interaction. The materials before and after modification were characterized and tested for mercury removal, including sorption kinetics and isotherms, the effects of adsorbent dosage, initial pH, and ionic strength. Pseudo-second-order sorption kinetic model (R² = 0.992~1.000) and Langmuir sorption isotherm model (R² = 0.964~0.998) fitted well with the sorption data of mercury. GOS had the most –SH groups with the largest adsorption capacity for Hg²⁺ and CH₃Hg⁺ (449.6 and 127.5 mg/g), followed by ACS (235.7 and 86.7 mg/g) and BCS (175.6 and 30.3 mg/g), which were much larger than GO (96.7 and 4.9 mg/g), AC (81.1 and 24.6 mg/g), and BC (95.6 and 9.4 mg/g). GOS and ACS showed stable mercury adsorption properties at a wide pH range (2~9) and ionic strength (0.01~0.1 mol/L). Mercury maybe removed by ligand exchange, surface complexation, and electrostatic attraction.

     

Size distribution, characteristics and sources of heavy metals in haze episod in Beijing

Size segragated samples were collected during high polluted winter haze days in 2006 in Beijing, China. Twenty nine elements and 9 water soluble ions were determined. Heavy metals of Zn, Pb, Mn, Cu, As, Cr, Ni, V and Cd were deeply studied considering their toxic effect on human being. Among these heavy metals, the levels of Mn, As and Cd exceeded the reference values of National Ambient Air Quality Standard （GB3095-2012） and guidelines of World Health Organization. By estimation, high percentage of atmospheric heavy metals in PM2.5 indicates it is an effective way to control atmospheric heavy metals by PM2.5 controlling. Pb, Cd, and Zn show mostly in accumulation mode, V, Mn and Cu exist mostly in both coarse and accumulation modes, and Ni and Cr exist in all of the three modes. Considering the health effect, the breakthrough rates of atmospheric heavy metals into pulmonary alveoli are： Pb （62.1%） 〉 As （58.1%） 〉 Cd （57.9%） 〉 Zn （57.7%） 〉 Cu （55.8%） 〉 Ni （53.5%） 〉 Cr （52.2%） 〉 Mn （49.2%） 〉 V （43.5%）. Positive matrix factorization method was applied for source apportionment of studied heavy metals combined with some marker elements and ions such as K, As, SO42- etc., and four factors （dust, vehicle, aged and transportation, unknown） are identified and the size distribution contribution of them to atmospheric heavy metals are discussed.     

Mapping the cost risk of agricultural residue supply for energy application in rural China

This research aims to shed light on the interaction mechanism of cost risks for biomass material supply in power generation, especially for biomass-coal dual-fuel systems. Firstly, a game model is established to analyze interactions among factors including unit procurement cost, unit transportation cost, basic price and coal price for crop residue collection. Secondly, a Monte Carlo simulation is implemented to compare the profit increase under material competition with that under price alliance. The methodology is illustrated with a case study in a biomass power plant in Shandong Province, China. It shows that developing a price alliance will benefit both the allied enterprises and the local collection area in most circumstances. Thirdly, a risk tolerance area approach is applied in mapping the cost risk and in explaining the risky circumstances of the case study.     

西宁市非采暖季和采暖季PM2.5中14种金属元素特征

于2012年11月采暖季和2013年9月非采暖季,在青藏高原典型城市西宁市4个采样点采集细颗粒物(PM_(2.5))样品,共获得40个有效样品。用微波消解-ICP-MS法、原子荧光法分析了样品中14种重点防控金属。结果表明:14种重点防控金属中Ag、Tl平均质量浓度为0.10~0.50 ng/m~3,Co、Sb、Hg平均质量浓度为0.50~4.00 ng/m~3,V、Cd、Cr、Ni、Cu、As平均质量浓度为4.00~50.0 ng/m~3,Mn、Pb、Zn平均质量浓度为50.0~2 000 ng/m~3。采样期间,采暖季相比非采暖季,PM_(2.5)质量浓度有下降趋势,不同采样区金属元素浓度有增有减。富集因子分析结果表明,重点防控金属元素在非采暖季主要来源于土壤风沙扬尘、机动车尾气和工业排放,采暖季主要来源于土壤风沙扬尘、燃煤、燃油、机动车尾气和工业排放。非采暖季Zn、Ag、Cd、Hg、Tl和Pb富集因子较高,采暖季Zn、As、Ag、Cd、Sb、Hg、Tl、Pb富集因子较高,更容易受到人为源的影响。     

Effect of cold exposure and capsaicin on the expression of histone acetylation and Toll-like receptors in 1,2-dimethylhydrazine-induced colon carcinogenesis

Environmental Science and Pollution Research - Previous studies have indicated that capsaicin-rich diet and cold weather have shown strong association with tumor incidence. Thus, we investigated...     

Graphitic carbon nitride/biochar composite synthesized by a facile ball-milling method for the adsorption and photocatalytic degradation of enrofloxacin

In order to enhance the removal performance of graphitic carbon nitride (g-C₃N₄) on organic pollutant, a simultaneous process of adsorption and photocatalysis was achieved via the compounding of biochar and g-C₃N₄. In this study, g-C₃N₄ was obtained by a condensation reaction of melamine at 550°C. Then the g-C₃N₄/biochar composites were synthesized by ball milling biochar and g-C₃N₄ together, which was considered as a simple, economical, and green strategy. The characterization of resulting g-C₃N₄/biochar suggested that biochar and g-C₃N₄ achieved effective linkage. The adsorption and photocatalytic performance of the composites were evaluated with enrofloxacin (EFA) as a model pollutant. The result showed that all the g-C₃N₄/biochar composites displayed higher adsorption and photocatalytic performance to EFA than that of pure g-C₃N₄. The 50% g-C₃N₄/biochar performed best and removed 45.2% and 81.1% of EFA (10 mg/L) under darkness and light with a dosage of 1 mg/mL, while g-C₃N₄ were 19.0% and 27.3%, respectively. Besides, 50% g-C₃N₄/biochar showed the highest total organic carbon (TOC) removal efficiency (65.9%). Radical trapping experiments suggested that superoxide radical (?O₂^?) and hole (h⁺) were the main active species in the photocatalytic process. After 4 cycles, the composite still exhibited activity for catalytic removal of EFA.     

Vertical response of microbial community and degrading genes to petroleum hydrocarbon contamination in saline alkaline soil

A column microcosm was conducted by amending crude oil into Dagang Oilfield soil to simulate the bioremediation process. The dynamic change of microbial communities and metabolic genes in vertical depth soil from 0 to 80 cm were characterized to evaluate the petroleum degradation potential of indigenous microorganism. The influence of environmental variables on the microbial responds to petroleum contamination were analyzed. Degradation extent of 42.45% of n-alkanes(C8–C40) and 34.61% of 16ΣPAH were reached after 22 weeks. Relative abundance of alkB, nah, and phe gene showed about 10-fold increment in different depth of soil layers. Result of HTS profiles demonstrated that Pseudomonas, Marinobacter and Lactococcus were the major petroleum-degrading bacteria in0–30 and 30–60 cm depth of soils. Fusarium and Aspergillus were the dominant oil-degrading fungi in the 0–60 cm depth of soils. In 60–80 cm deep soil, anaerobic bacteria such as Bacteroidetes, Lactococcus, and Alcanivorax played important roles in petroleum degradation.Redundancy analysis(RDA) and correlation analysis demonstrated that petroleum hydrocarbons(PHs) as well as soil salinity, clay content, and anaerobic conditions were the dominant effect factors on microbial community compositions in 0–30, 30–60, and 60–80 cm depth of soils, respectively.     

滨海不同生境下盐地碱蓬生物量分配特征研究

盐地碱蓬是黄河三角洲重要的先锋植物,抗盐能力强,分布范围广,对维持该地区生态系统稳定和演替发挥着重要作用。通过野外取样测定,研究了潮间带和潮上带盐地碱蓬种群的形态及生物量分配特征。在个体大小上,潮间带盐地碱蓬在株高和地径上显著低于潮上带盐地碱蓬;潮上带盐地碱蓬密集分布的株高高于散生分布,而生物量低于散生分布。在生物量分配特征上,潮间带盐地碱蓬Ⅰ以发展花、叶为主,潮上带盐地碱蓬Ⅱ的密集分布以优先发展茎为主,潮上带盐地碱蓬Ⅲ的散生分布以发展枝为主,属于种群发展的稳定阶段。因此,盐地碱蓬通过形态特征及生物量分配特征的调节,以适应潮间带和潮上带的不同生境特征,从而达到种群维持和土壤改良的目的。     

川东北复杂地形应急监测技术研究和应用

针对川东北复杂地形,设计了应急监测的系统架构和功能,研究了应急监测的关键技术,提出了利用Ad hoc网络、移动定位技术和生命体征监测技术等,可实时监测现场环境数据和现场第一应急人员的位置和生命特征参数,确保现场救援人员的生命安全,为指挥人员提供有效的信息支持.     

油田油泥(砂)废弃物排放状况及处理技术

中国油田及石油化工行业每年油泥(砂)的排放量达到80多万吨,已严重制约油田的可持续发展。油泥(砂)中石油含量达10%～30%,还含有多环芳烃、重金属等污染物,可对生态环境和人体健康造成危害。国内外已广泛开展了油泥(砂)处理技术的研究。油泥(砂)处理技术包括资源回收技术、无害化处理技术和综合利用技术。本文简述了水洗处理技术、生物处理技术和热解气化焚烧工艺,并对不同处理技术的优缺点进行了比较。应结合中国国情及成本等方面综合考虑选用不同的处理方法,实现油泥的减量化、无害化、资源化、清洁化处理。