Optimizing food waste hydrothermal parameters to reduce Maillard reaction and increase volatile fatty acid production

The occurrence of the Maillard reaction and melanoidins formation during the hydrothermal treatment of food waste can reduce the yield of volatile fatty acids (VFA); however, few studies have investigated the adverse effects of the Maillard reaction. This study identified the impact of hydrothermal treatment parameters on hydrolysis and melanoidins formation and optimized the hydrothermal treatment conditions to enhance VFA production by minimizing the impact of the Maillard reaction. A response surface methodology was employed to optimize the hydrothermal treatment parameters and VFA production was evaluated. Results showed that temperature, reaction time, and pH were significant interacting factors with respect to hydrolysis and melanoidins formation while the C/N ratio and moisture content of food waste had little impact. The optimal conditions for hydrothermal treatment (temperature of 132 °C, reaction time of 27 min, and a pH of 5.6) enhanced VFA production by 22.1%. Under optimal hydrothermal treatment conditions, a higher initial C/N ratio further increased VFA production.     

Hepatitis A Virus Disinfection in Water by Solar Photo–Fenton Systems

This study evaluates and compares the effectiveness of solar photo–Fenton systems for the inactivation of hepatitis A virus (HAV) in water. The effect of solar irradiance, dark- Fenton reaction and three different reactant concentrations (2.5/5, 5/10 and 10/20 mg/L of Fe²⁺/H₂O₂) on the photo–Fenton process were tested in glass bottle reactors (200 mL) during 6 h under natural sunlight. Disinfection kinetics were determined both by RT-qPCR and infectivity assays. Mean water temperatures ranged from 25 to 27.3 °C, with a maximum local noon UV irradiances of 22.36 W/m². Photo–Fenton systems yielded increased viral reduction rates in comparison with the isolated effect under the Fenton reaction in darkness (negligible viral reduction) or the solar radiation (0.25 Log of RNA reduction). With the highest concentration employed (10–20 mg/L Fe²⁺–H₂O₂), an average RNA reduction rate of ~ 1.8 Log (initial concentration of 10⁵ pfu/mL) and a reduction of 80% in the infectivity capacity were reached. Results showed a strong synergistic effect between Fe²⁺/H₂O₂ and sunlight, demonstrating that significant disinfection rates of HAV under photo–Fenton systems may occur with relatively higher efficiency at middle environmental temperatures and without the need for an energy-intensive light source.     

Temperature Dependent Depuration of Norovirus GII and Tulane Virus from Oysters (Crassostrea gigas)

Raw oysters are considered a culinary delicacy but are frequently the culprit in food-borne norovirus (NoV) infections. As commercial depuration procedures are currently unable to efficiently eliminate NoV from oysters, an optimisation of the process should be considered. This study addresses the ability of elevated water temperatures to enhance the elimination of NoV and Tulane virus (TuV) from Pacific oysters (Crassostrea gigas). Both viruses were experimentally bioaccumulated in oysters, which were thereafter depurated at 12 °C and 17 °C for 4 weeks. Infectious TuV and viral RNA were monitored weekly for 28 days by TCID₅₀ and (PMAxx-) RT-qPCR, respectively. TuV RNA was more persistent than NoV and decreased by?<?0.5 log₁₀ after 14 days, while NoV reductions were already?>?1.0 log₁₀ at this time. For RT-qPCR there was no detectable benefit of elevated water temperatures or PMAxx for either virus (p?>?0.05). TuV TCID₅₀ decreased steadily, and reductions were significantly different between the two temperatures (p?<?0.001). This was most evident on days 14 and 21 when reductions at 17 °C were 1.3–1.7 log₁₀ higher than at 12 °C. After 3 weeks, reductions?>?3.0 log₁₀ were observed at 17 °C, while at 12 °C reductions did not exceed 1.9 log₁₀. The length of depuration also had an influence on virus numbers. TuV reductions increased from?<?1.0 log₁₀ after seven days to?>?4.0 log₁₀ after 4 weeks. This implies that an extension of the depuration period to more than seven days, possibly in combination with elevated water temperatures, may be beneficial for the inactivation and removal of viral pathogens.

     

中亚热带常绿阔叶林湿沉降过程中盐基离子变化特征

基于野外实验和室内实验相结合的方法,于2012年9月至2013年8月对四面山常绿阔叶林大气降水、穿透水、地表枯透水、土壤渗滤液进行了持续一年的森林不同层次盐基离子季节动态变化特征的研究.结果表明,四面山大气降水全年pH平均值为4.90,最大值为5.14,大气降水明显偏酸性;土壤层和林冠层能使降雨的p H值有所升高,其中土壤层对p H值的调升幅度最大,其次为森林冠层;森林冠层只对Na~+有一定的截留作用,降雨能够淋溶森林冠层的Ca~(2+)、Mg~(2+)、K~+;研究结果也表明,枯枝落叶的降解是导致各盐基离子质量浓度在枯透水中增加的主要原因;枯透水下渗的过程淋溶了森林土壤中的Ca~(2+)、Mg~(2+)、Na~+.四面山大气降水经过森林生态系统后Ca~(~(2+))、Mg~(2+)、Na~+、K~+的总截留率分别为33.82%、-7.06%、74.36%、42.87%,森林生态系统对Ca~(2+)、Na~+、K~+表现出了截留作用,其中对Na~+截留率最大.     

Effects of bile salts and divalent cations on the adsorption of norfloxacin by agricultural soils

The effects of bile salts （sodium cholate and sodium deoxycholate, 0-20 mmol/L）, divalent cations （Ca^2＋, Mg^2＋, Cu^2＋ and Zn^2＋, 0-20 mmol/L） or pH （3.0-10.0） on the adsorption of norfloxacin by three selected soils （Paddy_H, Paddy_G and Red_J） were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu^2＋ 〉 Mg^2＋ 〉 Ca^2＋ 〉 Zn^2＋, and by red soil, which followed an order of Cu^2＋ 〉 Zn^2＋ 〉 Ca^2＋ 〉 Mg^2＋. The adsorption of norfloxacin （by the soils studied） sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces.     

pH和共存阳离子对草莓茎吸附水体氨氮的影响

为了开发新型氨氮吸附剂和探讨环境因素对氨氮吸附的影响,以草莓茎为吸附材料,通过批平衡法研究了不同初始pH、共存阳离子、初始浓度和温度下氨氮去除的特点.结果表明,等温吸附符合Langmuir和Freundlich这2种模型,理论最大吸附量qm在15、25和35℃下分别为3.05、4.24和4.79 mg.g-1.温度升高有利于草莓茎对氨氮的吸附.草莓茎吸附氨氮最适初始pH为4～8.低pH减少草莓茎表面负电荷,高pH减少溶液中NH 4+的含量,都减少氨氮的吸附.草莓茎对溶液pH的缓冲则缓和了两者对氨氮吸附的影响.共存阳离子K+、Na+、Ca2+、Mg2+对草莓吸附铵离子没有竞争作用,而Zn2+、Al3+则由于其水解降低溶液的pH而显著降低草莓茎对氨氮的吸附.草莓茎吸附氨氮的应用pH范围较广且不易受废水中常见金属阳离子的干扰,说明草莓茎不仅可以作为废水中氨氮的吸附剂原料,而且较大多数矿物原料还有其自身的优势.     

三种阳离子对地下水总硬度的影响

通过室内浸泡实验改变三种阳离子Na+、H+、NH+4浓度、浸泡时间,对其动力学和热力学行为进行研究,分析土壤浸出液总硬度变化情况,以找出地下水总硬度随外界条件的变化规律,探究地下水硬度变化机理,为减轻该区地下水硬度升高对人类健康、工农业生产的危害及深入研究地下水总硬度变化机理提供理论依据。实验结果表明:三种阳离子对土壤浸出液总硬度影响不同,NH+4交换出的总硬度最大,H+次之,Na+最小;对同一土层土壤,加入外界浸泡液的浓度越大,交换总硬度的速率越大,交换量也越大;三种阳离子的浸泡液可在1h内将土壤中大部分钙镁交换出,遇有长达1h的强降雨或漫灌,Ca2+、Mg2+会逐步向下迁移,最终引起地下水总硬度升高。     

Japanese Papilio butterflies puddle using Na+ detected by contact chemosensilla in the proboscis

Many butterflies acquire nutrients from non-nectar sources such as puddles. To better understand how male Papilio butterflies identify suitable sites for puddling, we used behavioral and electrophysiological methods to examine the responses of Japanese Papilio butterflies to Na⁺, K⁺, Ca²⁺, and Mg²⁺. Based on behavioral analyses, these butterflies preferred a 10-mM Na⁺ solution to K⁺, Ca²⁺, and Mg²⁺ solutions of the same concentration and among a tested range of 1?mM to 1?M NaCl. We also measured the ion concentrations of solutions sampled from puddling sites in the field. Na⁺ concentrations of the samples were up to 6?mM, slightly lower than that preferred by butterflies in the behavioral experiments. Butterflies that sipped the 10?mM Na⁺ solution from the experimental trays did not continue to puddle on the ground. Additionally, butterflies puddled at sites where the concentrations of K⁺, Ca²⁺, and/or Mg²⁺ were higher than that of Na⁺. This suggests that K⁺, Ca²⁺, and Mg²⁺ do not interfere with the detection of Na⁺ by the Papilio butterfly. Using an electrophysiological method, tip recordings, receptor neurons in contact chemosensilla inside the proboscis evoked regularly firing impulses to 1, 10, and 100?mM NaCl solutions but not to CaCl₂ or MgCl₂. The dose?Cresponse patterns to the NaCl solutions were different among the neurons, which were classified into three types. These results showed that Japanese Papilio butterflies puddle using Na⁺ detected by the contact chemosensilla in the proboscis, which measure its concentration.     

One-pot synthesis of Fe/Cu-SSZ-13 catalyst and its highly efficient performance for the selective catalytic reduction of nitrogen oxide with ammonia

Series of Fe/Cu-SSZ-13 catalysts with different Fe loading content were synthesized by simple one-pot strategy. The obtained catalysts were subjected to selective catalytic reduction (SCR) of NO_x with NH₃ and were characterized by various techniques. The results show that Fe_0.63/Cu_1.50-SSZ-13 catalyst with proper Fe content exhibits excellent catalytic activity with widest operation temperature window from 160 to 580°C, excellent hydrothermal stability as well as good resistance to sulfur poisoning when compared with Cu-SSZ-13, signifying its great potential for practical applications. Further characterizations reveal that the synthesized Fe/Cu-SSZ-13 catalysts present typical chabazite (CHA) structure with good crystallinity, while isolated Cu²⁺ and monomeric Fe³⁺ are revealed as the predominant copper and iron species. At low temperatures, isolated Cu²⁺ species act as primary active sites for SCR reaction, while monomeric Fe³⁺ species provide sufficient active sites for sustain the SCR activity at high temperature. Moreover, Fe over doping would lead to the damage of zeolite structure, destruction of isolated Cu²⁺ site, as well as the formation of highly oxidizing Fe₂O₃, thus causing deterioration of catalytic performances.     

土壤对酸沉降缓冲机制探讨

一、前言 土壤对酸沉降具有一定的缓冲作用,不同土壤的缓冲能力也各不相同。那么,土壤缓冲作用的本质是什么,不同土壤为什么具有不同的缓冲能力,要解决这些问题,就必须要了解土壤的缓冲机制,了解土壤内部的化学过程。     

常规金属离子对Fe3O4磁性纳米颗粒悬浮和沉降的影响

水体中的有机质、无机盐及酸碱度是影响纳米材料迁移转化的主要因素.考察了Na~+、Mg~(2+)、Ca~(2+)、Sr~(2+)和Ba~(2+)对Fe_3O_4磁性纳米材料(Magnetic Nanoparticles,MNPs)的沉降作用.结果表明,Fe_3O_4MNPs的沉降作用是水体pH、金属离子化合价、离子强度共同影响的结果.整体上,碱土金属离子较Na~+更能加速Fe_3O_4MNPs的沉降.当pH为5.0时,浓度低于1.0 mmol·L~(-1)的Na~+、Mg~(2+)和Ca~(2+)有助于Fe_3O_4MNPs的悬浮;当浓度大于1.0 mmol·L~(-1)时,较强的离子强度促使Fe_3O_4MNPs团聚,发生沉降.当pH为9.0时,碱土金属离子较Na~+更能促使Fe_3O_4MNPs聚沉.因此,纳米颗粒在水体中的扩散和聚沉需要综合考虑金属离子种类和浓度.     

Deactivation of Cu-SAPO-34 by urea-related deposits at low temperatures and the regeneration

Selective catalytic reduction(SCR) with urea catalyzed by Cu-SAPO-34 is an effective method to eliminate NO_x from diesel exhaust. However, urea-related deposits may form during cold-start and urban driving due to low exhaust temperatures. The activity of CuSAPO-34 at 175°C is significantly degraded by urea exposure, and 300°C is required for regeneration. Through in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) and temperature-programmed hydrolysis studies, the dominant stable deposit at 175°C is identified as biuret, which can be eliminated at 300°C. The urea-derived deactivation and regeneration mechanisms of Cu-SAPO-34 were compared with those of anatase-supported catalysts.     

粉煤灰提铝中间产物合成4A分子筛对氨氮的吸附行为研究

采用粉煤灰提铝中间产物合成4A分子筛,利用XRD、SEM、热重分析、化学成分分析、阳离子交换容量对4A分子筛进行表征.考察吸附时间、pH、分子筛投加量、氨氮初始浓度、共存阳离子对其吸附性能的影响,研究其对模拟废水中氨氮的吸附效果,并结合准二级动力学方程、吸附等温线研究吸附性能和机理.结果表明,初始浓度为50 mg·L~(-1)、4A分子筛投加量为5 g·L~(-1)、pH值为6~9、吸附时间为80 min时氨氮去除率可达71.34%;随着氨氮初始浓度升高,其去除率降低,吸附容量增加;共存阳离子Na~+、K~+、Ca~(2+)对NH_4~+有强烈的竞争吸附,Mg~(2+)无明显竞争作用.吸附过程符合准二级动力学方程和Freundlich模型.Langmuir吸附等温线显示最大吸附容量为20 mg·g~(-1).     

Temperature-Dependent Persistence of Human Norovirus Within Oysters (<Emphasis Type="Italic">Crassostrea virginica</Emphasis>)

This study characterizes the persistence of human norovirus in Eastern oysters (Crassostrea virginica) held at different seawater temperatures. Oysters were contaminated with human norovirus GI.1 (Norwalk strain 8FIIa) by exposing them to virus-contaminated water at 15 °C, and subsequently holding them at 7, 15, and 25 °C for up to 6 weeks. Viral RNA was extracted from oyster tissue and hemocytes and quantitated by RT-qPCR. Norovirus was detected in hemocytes and oysters held at 7 and 15 °C for 6 weeks and in hemocytes and oysters held at 25 °C for up to 2 and 4 weeks, respectively. Results confirm that NoV is quite persistent within oysters and demonstrate that cooler water temperatures extend norovirus clearance times. This study suggests a need for substantial relay times to remove norovirus from contaminated shellfish and suggests that regulatory authorities should consider the effects of water temperature after a suspected episodic norovirus-contamination event.     

UV/H2O2氧化降解克拉霉素的反应动力学及影响因素

克拉霉素用量大、检出频率高、生态风险大,已被欧盟列为优先监测污染物.针对传统污水处理厂难以完全去除克拉霉素的问题,主要研究了UV/H_2O_2降解克拉霉素的效果和反应动力学,探讨了pH、天然有机质(NOM)和水中共存阴、阳离子对UV/H_2O_2降解克拉霉素的影响.结果表明:单一UV对克拉霉素的光降解符合准一级反应动力学模型,其反应速率常数为0.0016 min~(-1).UV/H_2O_2对克拉霉素的降解符合准一级反应动力学模型,且克拉霉素的降解速率随H_2O_2浓度的增大而增大,在H_2O_2浓度为40 mmol·L~(-1)时,克拉霉素降解的反应速率常数为0.0284min~(-1).克拉霉素与·OH的二级反应速率常数为(2.36±0.20)×10~(10)L·mol~(-1)·s~(-1).碱性条件有利于克拉霉素的降解;NOM(2~10 mg·L~(-1))会抑制克拉霉素的降解,且随NOM浓度增大而增大;共存阴离子CO_3~(2-)对克拉霉素降解无影响,HCO_3~-、NO_3~-、Cl~-会抑制克拉霉素的降解,抑制程度的大小顺序为NO_3~-HCO_3~-Cl~-;共存阳离子Ca~(2+)、Mg2+、Cu~(2+)、Fe~(3+)会抑制克拉霉素的降解,抑制程度的大小顺序为Fe~(3+)Cu~(2+)Mg2+Ca~(2+).     

Impacts of climate variability and changes on domestic water use in the Yellow River Basin of China

We present a methodology for using a domestic water use time series that were obtained from Yellow River Conservancy Commission, together with the climatic records from the National Climate Center of China to evaluate the effects of climate variability on water use in the Yellow River Basin. A suit of seven Global Circulation Models (GCMs) were adopted to anticipate future climate patterns in the Yellow River. The historical records showed evidences of rises in temperature and subsequent rises in domestic water demand in the basin. For Upstream of Longyangxia region, the impact was the least, with only 0.0021?×?10⁸ m³ for a temperature increase of 1 °C; while for Longyangxia-Lanzhou region, domestic water use was found to increase to 0.18?×?10⁸ m³ when temperature increases 1 °C. Downstream of Huayuankou was the region with the most changes in temperature that gave the highest increase of 1.95?×?10⁸ m³ in domestic water demand for 1 °C of change of temperature. Downstream of Huayuankou was identified as the most vulnerable area, where domestic water demand increases nearly by 42.2 % with 1 °C increase of temperature. Judging from the trends of temperature range, we concluded that future temperature in Yellow River Basin has an increasing tendency. This could worsen the existing issues of domestic water demand and even more to trigger high competition among different water-using sectors.     

不同植被类型及土壤对径流水化学特征的影响

在不同植被类型覆盖条件下,对降雨形成地表径流和地下径流的化学成分变化及其与土壤剖面性质的关系进行分析,结果表明:地表径流和地下径流的化学特征与雨水基本相同,阳离子主要以Ca²⁺为主,离子排序为Ca²⁺>K⁺>Na⁺>Mg²⁺>NH₄⁺,阴离子以SO₄^2-为主,SO₄^2->NO₃^->Cl^-.降雨形成地表径流和地下径流后,各成分浓度发生了明显的变化,水体中主要的阴阳离子如Ca²⁺、Mg²⁺、K⁺、Na⁺、SO₄^2-、Cl^-等浓度增加,与雨水相比为内贮型化学成分,地下径流中Ca²⁺、Mg²⁺、SO₄^2-和Cl^-增加的幅度显著高于地表径流.相关分析结果显示,地下径流pH受到土壤pH的强烈影响,受土壤胶体吸附的影响,水体中Ca²⁺、Mg²⁺、K⁺、Na⁺等阳离子与土壤交换性阳离子之间一般呈负相关的关系,由于阴离子容易随水流失,水体中SO₄^2-、NO₃^-和Cl^-与土壤相关离子之间普遍呈正相关关系.     

云南鹤庆西山岩溶地下水主要离子雨季和旱季对比及来源分析

鹤庆西山岩溶地下水是当地居民的主要生活用水来源,本文综合运用统计学分析方法对地下水主离子的雨季和旱季变化特征及其来源进行了研究。结果表明,研究区岩溶地下水主要补给来源为大气降水,TDS介于113.3~180.76mg/L属弱矿化度水,总硬度(Ca2++Mg2+)介于38~53 mg/L之间属于极软水。HCO-3和(Ca2++Mg2+)分别占主要阴阳离子的79.6%~95.5%和75%~94%,按照O.A.阿列金分类法研究区水质为HCO3-Ca·Mg型水。Ca2+、Mg2+、Cl-、SO2-4及HCO-3均未出现季节性变化,Na+与NO-3为丰水期枯水期,K+出现异常为丰水期枯水期。参照我国及世界卫生组织饮用水标准,锰矿黑龙潭泉受人为活动的影响较大,不宜长期饮用;其他地区主要离子浓度不会对人体产生危害。     

玉龙雪山地区不同海拔高度降水中常量无机离子特征分析

运用海盐示踪法计算了云南省丽江市玉龙雪山2005-07-26～2006-07-31不同海拔高度降水中常量无机离子非海洋来源的比例,计算结果显示Cl^-、Na⁺海洋源比重较高,平均海洋源比重分别为74.79％、73.53％. NO^-₃、SO^2-₄、K⁺ 、Mg²⁺ 、Ca²⁺主要是非海洋源,平均非海洋源所占的比重依次为100％、93.54％、97.29％、81.77％、99.66％. 统计图显示阳离子浓度的变化远远大于阴离子,阳离子浓度区间为0.51～5.26 mg/L,阴离子浓度区间为0.99～4.90 mg/L,由此推断阳离子来源构成比较复杂. 分析表明陆源离子,尤其是近源陆源离子对该地区降水的无机离子构成和离子浓度影响较大,2400～2950 m人类活动导致阴离子浓度较高,2950～4800 m降水的离子浓度受局地环流的影响较大,玉龙雪山地区基岩以石灰岩为主是造成降水中阳离子,尤其是Ca²⁺和Mg²⁺浓度较大的主要原因.     

An assessment of carbon stock for various land use system in Aravally mountains, Western India

Reducing carbon emissions from deforestation and degradation in developing countries is of the central importance in efforts to combat climate change. A study was conducted to measure carbon stocks in various land-use systems including forms and reliably estimates the impact of land use on carbon (C) stocks in the forest of Rajasthan, western India (23°3′–30°12′N longitude and 69°30′–78°17′E). 22.8% of India is forested and 0.04% is the deforestation rate of India. In Indian forest sector of western India of Aravally mountain range covered large area of deciduous forest and it’s very helpful in carbon sequestration at global level. The carbon stocks of forest, plantation (reforestation) and agricultural land in aboveground, soil organic and fine root within forest were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (533.64?±?37.54 Mg·ha^?1, simplified expression of Mg (carbon) ·ha^?1) was significantly greater (P?<?0.05) than the plantation (324.37?±?15.0 Mg·ha^?1) and the agricultural land (120.50?±?2.17 Mg·ha^?1). Soil organic carbon in the forests (172.84?±?3.78 Mg·ha^?1) was also significantly greater (P?<?0.05) than the plantation (153.20?±?7.48 Mg·ha^?1) and the agricultural land (108.71?±?1.68 Mg·ha^?1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 30-cm layer and decreased with soil depth. The aboveground carbon (ABGC): soil organic carbon (SOC): fine root carbon ratios (FRC), was 8:4:1, 4:5:1, and 3:37:1 for the forest, plantation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land.