Kinetic and equilibrium isotherm studies for the adsorptive removal of Brilliant Green dye from aqueous solution by rice husk ash

The present study deals with the adsorption of Brilliant Green (BG) on rice husk ash (RHA). RHA is a solid waste obtained from the particulate collection equipment attached to the flue gas lines of rice husk fired boilers. Batch studies were performed to evaluate the influences of various experimental parameters like initial pH (pH0), contact time, adsorbent dose and initial concentration (C0) on the removal of BG. Optimum conditions for BG removal were found to be pH0 approximately 3.0, adsorbent dose approximately 6 g L(-1) of solution and equilibrium time approximately 5 h for the C0 range of 50-300 mg L(-1). Adsorption of BG followed pseudo-second-order kinetics. Intra-particle diffusion does not seem to control the BG removal process. Equilibrium isotherms for the adsorption of BG on RHA were analyzed by Freundlich, Langmuir, Redlich-Peterson (R-P), Dubnin-Radushkevich (D-R), and Temkin isotherm models using a non-linear regression technique. Langmuir and R-P isotherms were found to best represent the data for BG adsorption onto RHA. Adsorption of BG on RHA is favourably influenced by an increase in the temperature of the operation. Values of the change in entropy (DeltaS0) and heat of adsorption (DeltaH0) for BG adsorption on RHA were positive. The high negative value of change in Gibbs free energy (DeltaG0) indicates the feasible and spontaneous adsorption of BG on RHA.     

NaOH预处理对秸秆与蓝藻混合厌氧发酵产沼气的影响

以稻秸和蓝藻为原料,在实验室自制小型发酵装置内进行混合物料厌氧发酵实验,研究不同质量分数NaOH预处理对秸秆与蓝藻混合厌氧发酵产沼气的影响。结果表明,经过NaOH预处理后,稻秸组分被破坏,产气量较对照组有明显增加,发酵时间缩短。扫描电镜观察显示,经碱性预处理过的稻草秸秆孔隙度增大,机械组织暴露,酶解的有效比表面积增大,酶解速率加快。NaOH质量分数为6%的处理组产气效果最好,总产气量比对照组高出248%,且甲烷平均含量达到58.89%,预处理效果最为理想。     

流化床中煤与稻秆混烧污染物排放特性

在自主设计的流化床上开展煤与稻秆混烧的实验。通过对燃烧过程中烟气成分及飞灰含碳量的分析,研究了质量掺混比、燃烧温度、流化风速及二次风率对混烧的影响。实验结果表明,掺混稻秆有效改善了煤的燃烧特性,随着质量掺混比的增加,NOx、SO2及CO的排放浓度降低,飞灰含碳量降低。当掺混比由0%增加至30%、温度为850 ℃时,NOx排放浓度由506.25 mg·m-3降低至404.33 mg·m-3,SO2排放浓度由762.86 mg·m-3降低至522.86 mg·m-3。随着燃烧温度的增加,NOx与SO2排放浓度增加,而CO排放浓度和飞灰含碳量降低。随着流化速度的增加,NOx与SO2排放浓度增加,CO排放浓度和飞灰含碳量先降低后增加,并分别在流化速度0.234 m·s-1和0.26 m·s-1时达到最低。随着二次风率的增加,SO2排放浓度与飞灰含碳量降低,NOx排放浓度与CO排放浓度先减小后增加,均在20%二次风率时达到最低。     

PLA、PPC或PBAT与2次改性小麦秸秆全降解复合材料的力学性能与生态风险

制作复合材料是小麦秸秆资源化利用的有效途径之一。小麦秸秆的改性处理对制成的复合材料力学性能有很大影响,且不同的基体材料与小麦秸秆制成的复合材料性能也有所不同。以聚乳酸（PLA）、聚碳酸亚丙酯（PPC）、聚己二酸（PBAT）为基体材料,分别以改性前或碱处理及偶联剂方法2次改性后的小麦秸秆纤维为增强材料,采用压缩成型工艺制备了6种全降解复合材料,并对制成的6种复合材料进行了力学性能测试与比对;分析了3种改性后小麦秸秆制成的全降解复合材料的降解性能,并通过种子发芽实验研究了它们的浸提液的潜在生态风险。结果表明,2次改性小麦秸秆与基体材料制成的复合材料,其力学性能较原始秸秆与基体材料制成的复合材料有明显的增强,其拉伸、弯曲、冲击强度均有20%~50%的提升。3种可降解材料降解率由大到小的顺序为：PLA全降解复合材料 > PBAT全降解复合材料 > PPC全降解复合材料。质量分数1%的3种全降解复合材料浸提液对种子发芽过程基本不造成影响。     

粪秆混合厌氧发酵渗滤床工艺的消化性能

以玉米秸秆-牛粪为原料,利用自行设计的渗滤床反应器（Leach bed reactors）,对比研究了渗透液回流喷淋时间、喷淋量、发酵温度及粪秆比4因素对原料物能转化率的影响。结果表明：发酵结束后罐内物料的TS浓度在13%~15%之间,属于高浓度发酵范畴;9样品产气峰值出现在发酵后的10~14 d,物能转化率排序为L6 > L2 > L9 > L7 > L1 > L8 > L4 > L5 > L3;TS产气率相对较高的共同特点主要为35 ℃中温、较高的渗滤液回流量以及较高的粪秆比。通过TS产气率的直观分析,4因素对实验结果影响大小排序分别为发酵温度> 粪秆比 > 喷淋量 > 喷淋时间间隔,得到的最佳工况参数为喷淋时间间隔2 h、喷淋量4 L、发酵温度35 ℃、粪秆比1∶1,此条件下得到的平均TS产气率为（98.4±3.5）mL·g-1。方差分析结果表明,发酵温度、粪秆比及喷淋量对产气结果影响极显著,为控制渗滤床发酵工艺的主要参数。     

2015年南京市SO2、NO2、CO和O3的污染特征分析

分析了2015年南京市二氧化硫（SO2）、二氧化氮（NO2）、一氧化碳（CO）和臭氧（O3）的污染特征。南京市SO2、NO2、CO和O3的年均浓度分别为19.3 μg·m-3、50.2 μg·m-3、0.972 mg·m-3和114 μg·m-3;SO2和CO污染相对较轻,NO2和O3污染相对严重。SO2、CO和O3的日变化呈"单峰型",而NO2的呈"双峰型";SO2、NO2和CO浓度在冬季最高,夏季最低,而O3相反。秸秆焚烧产物的区域输送在夏收（6月）和秋收（11月）时节对南京市CO的贡献显著。各监测点及全市的气态污染物普遍表现出"反周末效应",指示外来污染源。     

Mercury levels and estimated total daily intakes for children and adults from an electronic waste recycling area in Taizhou, China: Key role of rice and fish consumption

In order to assess the potential health risks of Hg pollution, total mercury (T–Hg) and methyl mercury (MeHg) concentrations were determined in air, dust, surface soil, crops, poultry, fish and human hair samples from an electronic waste (e-waste) recycling area in Taizhou, China. High concentrations of T–Hg and MeHg were found in these multiple matrices, and the mean concentration was 30.7 ng/m³ of T–Hg for atmosphere samples, 3.1 μg/g of T–Hg for soil, 37.6 μg/g of T–Hg for dust, 20.3 ng/g of MeHg for rice and 178.1 ng/g of MeHg for fish, suggesting that the e-waste recycling facility was a significant source of Hg. The inorganic Hg (I–Hg) levels (0.84 μg/g) in hair samples of e-waste workers were much higher than that in the reference samples. Pearson''s correlation coefficients showed that strong positive correlations (p < 0.01) between hair I–Hg and time staying in industrial area (r = 0.81) and between MeHg and fish consumption frequency (r = 0.91), imply that workers were mainly exposed to Hg vapor through long-time inhalation of contaminated air and dust, while other population mainly exposed to MeHg through high-frequency fish consumption. The estimated daily intakes of Hg showed that dietary intake was the major Hg exposure source, and Hg intakes from rice and fish were significantly higher than from any other foods. The estimated total daily intakes (TDIs) of MeHg for both children (696.8 ng/(kg·day)) and adults (381.3 ng/(kg·day)) greatly exceeded the dietary reference dose (RfD) of 230 ng/(kg·day), implying greater health risk for humans from Hg exposures around e-waste recycling facilities.     

水稻和玉米的热氧化分解特性及几种动力学方法结果的比较

利用热重分析仪在空气气氛、不同的升温速率下对带壳稻谷粉和玉米粒粉进行了热重测试,依据热重实验数据,采用多种热解动力学分析方法计算了水稻和玉米的活化能数值并进行比较,结果表明水稻和玉米的热氧化反应活化能随着转化率出现先增加后降低的趋势,并在转化率为70%左右达到了极大值。     

Influence of rice straw burning on the levels of polycyclic aromatic hydrocarbons in agricultural county, Taiwan

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秸秆资源现状及秸秆沼气效益分析

介绍了农作物秸秆在我国的分布情况和秸秆的组成成分,阐述了将秸秆应用于沼气中的实际价值与研究进展,分析了秸秆沼气对环境、经济与社会的影响。