中国市政污泥中磷的含量与形态分布

于2016年采集了全国46个城市的市政污泥样品,运用SMT法测定了污泥中不同形态磷的含量.结果表明,我国市政污泥中总磷（TP）、无机磷（IP）、非磷灰石态无机磷（NAIP）、磷灰石态无机磷（AP）、有机磷（OP）和生物有效磷（NAIP+OP）的平均含量分别为（17.32±5.13）、（11.71±4.01）、（9.18±3.44）、（3.03±2.74）、（4.54±4.23）和（13.72±4.36）g·kg^-1.其中IP是污泥中磷的主要存在形态,占TP含量的60%以上;NAIP是主要的无机磷形态,占IP含量的66%以上.污泥中生物有效磷占TP含量的比例介于66.8%~96.1%之间,二者呈现极显著正相关关系（r=0.942,P<0.01）.市政污泥磷含量和排放量总体上呈现东高西低的空间分布规律.2016年随污泥处置排放入环境的磷达到了1.04×10⁵ t,其中1.95×10⁴ t随污泥农用进入土壤,4.69×10⁴ t进入填埋场,1.47×10⁴ t进入建筑材料中,2.34×10⁴ t经垃圾焚烧进入焚烧灰,4.50t被直接倾倒丢弃.与历史数据对比发现,我国市政污泥中总磷的含量呈现先升高、后降低的变化趋势.     

呼伦贝尔草原土壤粘粉粒组分对有机碳和全氮含量的影响

土壤在维持全球碳、氮循环中起着重要的作用。利用土壤粒级分组的方法,分析了呼伦贝尔草原土壤有机碳、全氮、阳离子交换量,并探讨其空间差异与成因。结果表明,(1)在呼伦贝尔草原,土壤有机碳(SOC)、全氮(TN)在不同地质发育的土壤类型中变异较大,而土壤粘粉粒组分中的有机碳(SOCclay-silt)、全氮(TNclay-silt)质量分数变异较小。在土壤表层(0~20cm),SOC、TN质量分数分别介于0.24%~3.70%、0.0316~0.3403mg/kg,而SOCclay-silt、TNclay-silt平均质量分数分别为3.61%±0.50%、0.3440%±0.0251%。在土壤下层(20~40cm),SOC、TN质量分数分别介于0.13%~2.91%、0.0175~0.2511mg/kg,而SOCclay-silt、TNclay-silt平均值分别为2.65%±0.63%、0.2622%±0.0923%。(2)土壤有机碳、全氮与土壤粘粉粒比例之间呈显著的正相关,表明土壤粘粉粒比例愈高,土壤有机碳和全氮在土壤中稳定性就愈强。     

废弃膨润土制备碳纳米材料及其吸附性能

将吸附结晶紫后的废弃膨润土在氮气保护下600℃加热3 h,用HF和HCl洗掉其中的膨润土片层,得到了一种新型碳纳米材料.对碳材料进行了XRD、TEM、N2吸附-脱附表征,研究结果显示,该材料石墨化程度较高,其2θ角在26.1°处有明显的峰衍射,接近于石墨烯在26.48°的峰;TEM表征结果显示碳材料为薄层皱褶结构.N2-BET测得所制材料比表面积为77.6 m2·g-1.对比了该碳材料和十六烷基三甲基溴化铵(CTMAB)改性膨润土以及减电荷四甲基氯化铵(TMA)改性膨润土常温下吸附硝基苯的效果,发现该材料对硝基苯吸附效果远胜于两种改性膨润土.吸附热力学实验显示吸附过程为放热和熵减少的自发过程.     

华南退化草坡自然恢复中物种多度分布的动态与模拟

华南地区退化草坡自然恢复过程中物种多度格局的动态及其模拟,尚缺乏较为系统的研究.文章探讨是否不同演替阶段群落适合不同的种多度模型,是否存在一个最佳模型以揭示演替过程中群落结构的某些内在数量特征;还要推导多个模型的尺度转换形式.为此,在地处南亚热带的鹤山退化草坡选取处于不同演替阶段的2个典型群落样地,分木本层和草本层调查每个维管植物种的多度;且选择7个具有不同函数形式和广泛代表性的种多度模型,均在倍程(即log2)尺度下拟合数据,运用卡方检验和调整决定系数评估各个模型的适合性.结果表明:(1)7个模型的适合性顺序为:对数柯西＞对数双曲正割＞对数正态＞对数级数＞生态位优先占领＞断棒＞重叠生态位,其中对数柯西适合全部数据,重叠生态位则全部不适合;(2)各模型适合与否和演替阶段无关;(3)左截断对数柯西模型预测的种多度分布显示,随着群落演替,上层(木本层)罕见种比例减少、常见种比例增多,下层(草本层)则相反,这与实际相符.对数柯西分布具有普适性,能最好地反映退化草坡自然恢复中种多度分布的格局与动态.     

臭氧胁迫下外源喷施亚精胺和EDU对小麦生理指标的影响

采用开顶式气室模拟研究外源喷施亚精胺(Spd)和EDU对O3胁迫下小麦生理指标变化的影响,测定的生理指标包括丙二醛含量(MDA)、超氧化物歧化酶活性(SOD)、过氧化物酶活性(POD)、过氧化氢酶活性(CAT)、可溶性蛋白质含量、还原型谷胱甘肽含量(GSH)、谷胱甘肽还原酶活性(GR)、抗坏血酸含量(ASA)和抗坏血酸过氧化物酶活性(APX)。结果表明,外源喷施Spd和EDU可不同程度地提高小麦叶片的SOD、POD、CAT、APX和GR活性,降低MDA和ASA含量,提高GSH和可溶性蛋白含量。当Spd的浓度为0.25、0.50和0.75mmol·L-1时,小麦叶片POD活性比对照处理提高90.0%～226.7%,CAT活性提高21.4%～40.6%,APX活性提高164.2%～191.0%,MDA含量降低9.7%～42.5%。喷施300mg·L-1EDU可导致小麦叶片POD、CAT和APX活性分别比对照处理提高76.8%、27.4%和128.1%,MDA和ASA含量降低,GSH含量提高25.6%。以上结果说明Spd和EDU是2种比较有效的缓解小麦O3胁迫的抗氧化剂,可用来防护O3对小麦的毒害。     

曲面效应法优化辅酶Q10发酵条件

以根癌土壤杆菌(Agrobacterium tum efaciens)1.1416的突变株AGR 0610为出发菌株,采用P lackett-Burm an设计法(P lackett-Burm an design,P-B)对影响AGR 0610发酵产辅酶Q10的相关因素进行了研究,选取到4种有显著效应的因素:糖蜜、大豆蛋白胨、玉米浆和蛋氨酸.再采用响应曲面法(response surface m ethodology,RSM)对这4种因素的最佳水平范围进一步探讨,得到二次回归方程,优化了培养基组成.当这4种因素分别取值为1.02%、0.49%、0.29%和0.34%时,辅酶Q10产量有最大预测值38.88 mg/L,并被实验所证实.图6表4参8     

南方某水库水体中抗生素生态与健康风险研究

环境中大量残留的抗生素将对生态环境和人体健康造成潜在危害。本研究采用风险商值法(RQ)评价了林肯霉素、红霉素(脱水)、罗红霉素、磺胺甲噁唑、磺胺二甲嘧啶、头孢呋辛、头孢氨苄、甲硝唑、阿莫西林和氯霉素10种抗生素对南方某水库水体产生的生态风险,并对10种抗生素进行了化学非致癌物风险评价。结果表明,7个采样点中共检出8种抗生素,残留量在1.2~130.0 ng·L~(-1)之间。红霉素(脱水)、林肯霉素、磺胺甲噁唑这3种抗生素在丰水期、枯水期的所有采样点均有检出,磺胺二甲嘧啶和头孢呋辛在枯水期的检出率也为100%,而氯霉素和阿莫西林在7个样点均未检出。风险评价结果表明,除个别样点外,该水库抗生素残留的整体风险不高。丰水期和枯水期A河水体中磺胺甲噁唑的生态风险商大于1,A河(丰水期和枯水期)、B河(丰水期)和库中3号样点(枯水期)的联合毒性风险商大于1,表明这3个样点的抗生素残留对生态环境存在较严重的威胁,其余采样点抗生素的联合毒性风险商处于0.1到1之间,需长期观测其抗生素的环境动态,以避免高风险危害的发生。该水库10种抗生素残留引起的非致癌物风险数量级在10~(-1)5到10~(-1)2之间,说明该水库中10种抗生素通过饮水途径引起的非致癌风险很低,远低于可接受风险水平,甚至远低于可忽略风险水平。     

Combination of steam-enhanced extraction and electrical resistance heating for efficient remediation of perchloroethylene-contaminated soil: Coupling merits and energy consumption

● Coupling merits of SEE and ERH were explored by a laboratory-scale device. ● SEE promotes the soil electrical conductivity and ERH process. ● Preheating soil by ERH improves the soil permeability and SEE. ● Combined method is more energy-efficient for perchloroethylene extraction. In situ thermal desorption (ISTD) technology effectively remediates soil contaminated by dense nonaqueous phase liquids (DNAPLs). However, more efforts are required to minimize the energy consumption of ISTD technology. This study developed a laboratory-scale experimental device to explore the coupling merits of two traditional desorption technologies: steam-enhanced extraction (SEE) and electrical resistance heating (ERH). The results showed that injecting high-density steam (> 1 g/min) into loam or clay with relatively high moisture content (> 13.3%) could fracture the soil matrix and lead to the occurrence of the preferential flow of steam. For ERH alone, the electrical resistance and soil moisture loss were critical factors influencing heating power. When ERH and SEE were combined, preheating soil by ERH could increase soil permeability, effectively alleviating the problem of preferential flow of SEE. Meanwhile, steam injection heated the soil and provided moisture for maintaining soil electrical conductivity, thereby ensuring power stability in the ERH process. Compared with ERH alone (8 V/cm) and SEE alone (1 g/min steam), the energy consumption of combined method in remediating perchloroethylene-contaminated soil was reduced by 39.3% and 52.9%, respectively. These findings indicate that the combined method is more favorable than ERH or SEE alone for remediating DNAPL-contaminated subsurfaces when considering ISTD technology.     

Long-term operation of biofilters for biological removal of ammonia

Biological removal of ammonia was investigated using two types of packing materials, compost and sludge in laboratory-scale biofilters (8l reactor volume). The aim of this study is to investigate the potential of unit systems packed with these supports in terms of ammonia emissions treatment. Experimental tests and measurements included analysis of removal efficiency, metabolic products, and results of long-term operation. The inlet concentration of ammonia applied was 20-200 mg m-3. The ammonia loading rates of 24.9-566 g NH3 m-3 d-1 to compost biofilter (BF3) and 24.9-472 g NH3 m-3 d-1 to sludge biofilter (BF4) were applied for 210 days, respectively. Removal efficiencies of the compost and sludge biofilters were in the range of 97-99% and 95-99%, respectively when the inlet concentration of ammonia was below 110 mg m-3, and the maximum elimination capacities were 288 and 243 g NH3m-3d-1, respectively. However, removal efficiency and elimination capacity of both biofilters significantly decreased as the inlet concentration increased to above 110 mg m-3. By using kinetic analysis, the maximum removal rate of ammonia, Vm, and the saturation constant, Ks, were determined for both packing materials and the value of Vm for compost was found to be larger. Periodic analysis of the biofilter packing materials showed the accumulation of the nitrification product NO3- in the operation. During the experiment, the pressure drops measured were very low. The use of both packing materials requires neither nutritive aqueous solution nor buffer solution.     

Application of microwave irradiation in the removal of polychlorinated biphenyls from soil contaminated by capacitor oil

The applicability of microwave irradiation in the removal of polychlorinated biphenyls (PCBs) from the soil heavily contaminated by capacitor oil was studied. Granular activated carbon (GAC) was added into the soil as a microwave-absorbing material to rapidly increase the temperature of the reaction system. Effects of sodium hypophosphite (SHP) and iron powder (IP) as reductants on PCB removal, as well as the effects of water content in soil, microwave power and the amount of GAC added were investigated. The results indicated that in the presence of SHP and GAC, about 80% of PCBs in soil were effectively removed by 10 min microwave irradiation, and the further addition of IP could raise the average removal efficiency to a higher level, more than 95%. In the removal of PCBs with the microwave/GAC/IP/SHP system, an appropriate amount of water proved to be helpful in promoting the removal of PCBs from soil by steam distillation and in acting as a co-solvent of SHP and H-donor of IP.