Two-step fast microwave-assisted pyrolysis of biomass for bio-oil production using microwave absorbent and HZSM-5 catalyst

A novel technology of two-step fast microwave-assisted pyrolysis(f MAP) of corn stover for bio-oil production was investigated in the presence of microwave absorbent(Si C) and HZSM-5catalyst. Effects of f MAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The f MAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1:100 to 1:20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step f MAP process, two-step f MAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio.     

稻壳沸石的合成及其对磷酸盐的吸附/脱附动力学

以稻壳为原料采用煅烧-水热合成法制备了合成沸石,运用XRD和SEM表征了合成沸石的特性,通过静态实验,研究了合成沸石对磷酸盐的吸附和脱附机理。结果表明:12 h后产物发现了Na P沸石的特征峰和亚晶结构,延长水热合成晶化的时间有利于沸石晶核的形成。沸石对磷酸盐的吸附机理符合伪二级模型,实测值与伪二级吸附动力学模型的拟合值相差在1.1%以内。颗粒内扩散速率是由膜扩散和内扩散共同控制,颗粒内扩散速率常数kp随初始浓度的增加而减小。升温有利于磷酸盐的脱附,MNa OH/P>8.0时(MNa OH/P为Na OH物质的量与吸附的磷酸盐物质的量之比),磷酸盐的脱附率可达82.9%。伪二级脱附动力学模型的拟合结果优于伪一级,拟合值与实测值相差在1.7%以内。     

改性Y沸石催化降解聚苯乙烯的研究

用热重分析方法研究了HY沸石与改性Y沸石(UHY)作为催化降解聚苯乙烯的催化剂对聚苯乙烯催化降解的作用及影响,对聚苯乙烯的催化降解与热降解反应产物进行了比较。结果表明,催化剂的存在能显著地降低聚苯乙烯的降解温度,催化剂的酸量和孔结构对聚苯乙烯的降解温度、活化能、积炭的生成量及裂解产物有很大的影响。     

聚烯烃类废塑料热分解技术中催化剂的选择和机理初探

研究使用不同催化剂情况下聚烯烃类废塑料热分解回收燃油的技术,并对废塑料的热分解机理进行了探讨．结果表明,自制的含大孔径分子筛的ＮＬＧ系列催化剂具有较好的催化性能,在裂解温度４３０℃,催化温度为３６０℃情况下,热分解后油产率为８７．５％,油品中汽油馏分达４１．３％,辛烷值为８８．３,每ｔ生产成本仅１２０００元左右,循环使用２０５余次后,仍保持良好的催化性能．     

沸石-茭白复合床技术脱氮中试研究

通过模拟农村暴雨径流水质 ,开展了沸石 茭白复合床技术处理农村暴雨径流的中试研究 ,分析了在不同工况下床体中各态氮的变化规律 ,结果表明 ,该项技术应用于暴雨径流氮的控制是可行的。     

沸石吸附焦化废水中氨氮的研究

利用沸石对氨氮的选择性吸附去除焦化废水中的氨氮,对不同粒度沸石、不同沸石投加量去除模拟废水和焦化废水进行了研究,结果表明,沸石对焦化废水中的氨氮有很强的选择吸附性;焦化废水中其它离子会降低沸石吸附氨氮的能力;粒度越细,沸石对焦化废水氨氮的去除速度越快;沸石吸附焦化废水等温线可用朗谬尔公式和费兰德利希公式来描述.     

纳米沸石对土壤Cd形态及大白菜Cd吸收的影响

通过室内培养试验研究了不同镉污染水平(1、5、10和15 mg·kg-1Cd)下,不同施用量(0、5、10和20 g·kg-1)的纳米沸石(NZ)和普通沸石(OZ)对土壤镉形态分配比例(FDC)随时间的变化情况,并通过盆栽试验进一步研究纳米沸石和普通沸石对土壤镉形态和大白菜Cd吸收的影响.室内培养试验表明,施用纳米沸石和普通沸石有效降低了土壤可交换态镉FDC,增加了铁锰氧化态镉FDC,在0~28 d的培养过程中,可交换态镉FDC呈先降后增后趋于平缓最后增加的趋势.培养结束时,沸石处理使可交换态镉FDC从0 d时的72.0%~88.0%降至30.0%~66.4%,各处理土壤镉主要以可交换态存在.盆栽试验表明,施用纳米沸石和普通沸石均显著降低了土壤可交换态镉含量和FDC,增加了碳酸盐结合态、铁锰氧化态、有机态和残渣态镉含量和FDC,以高量纳米沸石处理(20 g·kg-1)对可交换态镉的降低效果最好.土壤可交换态镉FDC与土壤p H呈显著负相关(P0.05),与大白菜地上部和根部镉含量呈极显著正相关(P0.01).施用沸石使1和5 mg·kg-1Cd水平土壤p H分别提高了1.8%~45.5%和6.1%~54.3%,土壤可交换态镉FDC分别降低了16.3%~47.7%和16.2%~46.7%,大白菜各部位镉含量分别降低了1.0%~75.0%和3.8%~53.2%,纳米沸石对土壤和植株镉的降低效果优于普通沸石.中低量(≤10 g·kg-1)的沸石对大白菜生长有明显的促进作用,而高量沸石(20 g·kg-1)则抑制了大白菜的生长.与普通沸石相比,纳米沸石显著提高大白菜生物量的同时,也显著降低了土壤可交换态镉含量和大白菜镉含量及镉积累量.     

Using a zeolite medium biofilter to remove organic pollutant and ammonia simultaneously

IntroductionWatershortageproblemisquiteseriousinmanycitiesofChina .Thereuseofmunicipalwastewaterisoneofthekeymethodstoreleasethisproblem .Makeupwaterforrecirculatingcoolingsystemisthelargestwaterusageinmanyfactories .Thewaterqualitystandardsforreclaimedwa…     

新型复合材料处理氮磷废水的性能研究

采用阳离子表面活性剂十六烷基三甲基溴化铵（Hexadecyl Trimethyl Ammonium Bromide，HDTMA）和稀土溶液氯化镧（LaCl₃）对人造沸石进行改性，以增强其对水中氨氮和总磷的同步去除效果.结果表明，HDTMA和LaCl₃可有效负载于人造沸石表面，且在pH为7的条件下，改性沸石对氨氮和总磷的去除率分别由改性前的75%和1%提高到95.67%和91.96%.影响因素的实验表明，改性沸石对不同浓度废水的氨氮和总磷去除率均达到90%以上；氮、磷的去除率随改性沸石投加量的增加而上升；准二级动力学模型适合描述改性沸石对氨氮吸附的动力学过程，准一级动力学模型适合描述改性沸石对总磷吸附的动力学过程；吸附等温线说明改性沸石对水中氨氮的吸附属于离子交换，对水中磷酸盐的吸附包含离子交换和化学吸附两种过程.此外，通过再生性能、负载强度和离子竞争的试验证明改性沸石能应用于实际生化尾水的氮、磷去除.     

Preparation and performance of novel APP/NaY–Fe suppressant for coal dust explosion

Coal dust explosion occurs easily in the coal chemical industry. To ensure safety in industrial production, NaY zeolite was used as carrier modified with Fe ions and combined with ammonium polyphosphate (APP) to prepare a novel composite suppressant for coal dust explosion. The explosion suppression performance of novel APP/NaY–Fe suppressant was investigated by flame propagation inhibition experiments. The results show that Fe ion modification can effectively improve the explosion suppression performance. By increasing content, the explosion suppression performance of the explosion suppressant increases. The maximum explosion pressure P_max of coal dust drops to 0.13 MPa when 50 wt% explosion suppressants were added, and the coal dust explosion cannot continue to expand. Complete suppression of explosion could be achieved by adding 66 wt% explosion suppressants. Combined with XRD, SEM and TG results, the explosion suppression mechanism was proposed. The novel explosion suppressant has high thermal stability, good dispersity and its explosion suppression components distribute uniformly. It shows good explosion suppression performance by the synergistic effect among explosion-suppression components.