质子化改性交联壳聚糖的制备及其吸附硫酸根离子的性能

以壳聚糖为原料,甲醛为氨基保护剂,戊二醛为交联剂,采用反相悬浮交联法制备交联壳聚糖,再对其进行质子化改性得到质子化改性交联壳聚糖吸附剂。通过正交实验对该吸附剂的制备条件进行优化,并对其吸附水中硫酸根（SO₄^2-）的吸附等温特性和动力学进行研究,最后对制备和吸附过程进行能谱分析（EDS）并对吸附剂进行了再生实验。实验结果表明,交联反应的优化条件为：反应温度50℃、反应时间6 h、甲醛：戊二醛：壳聚糖为4.5：0.5：3（质量比）;该吸附过程符合Langmuir吸附等温模型,在25℃（298 K）下,吸附容量最大可达133.87 mg/g;吸附过程较好地符合拟二级动力学模型;EDS分析表明了交联反应、质子化改性和吸附反应均已发生;该吸附剂的再生性能良好,可以重复使用。     

碱液预处理玉米秸秆的条件优化及添加剂的选择

利用稀NaOH溶液预处理玉米秸秆,以去除木质素,减少半纤维素、纤维素的损失为目的,采用响应曲面法对预处理条件进行优化,得到的最佳预处理条件为:NaOH溶液浓度0.77%(w/w),预处理时间16 h,温度45.6℃。并且,进一步研究了不同添加剂(聚乙二醇、吐温-80和尿素)与NaOH溶液协同作用下秸秆中木质素的去除效果,结果表明尿素与NaOH的混合溶液对木质素去除效果最显著。秸秆在45.6℃,0.77%NaOH和0.2%尿素混合溶液中浸泡16 h后,纤维素回收率为86.33%,半纤维素回收率为69.89%,木质素去除率为64.93%;与原秸秆相比,纤维素含量提高了31.70%,半纤维素含量提高了6.62%,木质素含量减少了46.48%。     

发酵类抗生素废水处理工艺及运行效果

介绍了内蒙古某抗生素废水处理厂的处理工艺流程、处理单元类型及其详细设计参数,通过对该污水处理厂半年内运行效果的调研,分析评价该污水处理系统的处理效果及出水指标;该水厂工艺流程对COD、TOC、氨氮、总氮、总磷、BOD和急性毒性的平均去除率分别为96.52%、95.83%、50.24%、55.20%、62.05%、98.52%和99.14%,COD、氨氮、总氮、总磷出水水质分别为477、438、556.7和7.69 mg/L,达到排放到城区下水道要求,园区内所有废水汇集到园区污水处理厂进行集中深度处理达标后排放水体。通过对该水厂工艺的介绍和水质分析,为我国抗生素生产企业面临的废水处理工艺类型选择及工程改造升级提供一定参考。     

Plasma versus Thermal Effects in Flue Gas NOx Reduction Using Ammonia Radical Injection

Abstract

A plasma-assisted ammonia injection technique was previously demonstrated as having the potential to remove NO_x from combustion flue gases at SCR-comparable levels without the use of catalysts. However, these demonstrations did not prove the advantage of plasma assistance because they did not explicitly account for enhanced radical production by bulk thermal heating. An experiment using hot ammonia injection was performed to separate this thermal effect from the effect of radical production via interaction with a plasma. Under excess air conditions, results show that a thermal effect does provide improved NO_x reduction, but not to the level achieved with the use of a plasma source. However, heating the injection gases provides only a minor improvement in NO_x reduction at NH₃/NO_x ratios and temperatures typical of commercial cold SNCR applications. The plasma effect in ammonia radical injection was also found to be significant, accounting for an additional 15% to 35% of absolute NO_x reduction beyond any thermal benefit at typical excess air conditions. The ammonia radical injection technique continues to show promise as an effective NO_x reduction alternative.     

Properties of Pyrolytic Chars and Activated Carbons Derived from Pilot-Scale Pyrolysis of Used Tires

Abstract

Used tires were pyrolyzed in a pilot-scale quasi-inert rotary kiln. Influences of variables, such as time, temperature, and agent flow, on the activation of obtained char were subsequently investigated in a laboratory-scale fixed bed. Meso-porous pores are found to be dominant in the pore structures of raw char. Brunauer-Emmett-Teller (BET) surfaces of activated chars increased linearly with carbon burnoff. The carbon burnoff of tire char achieved by carbon dioxide (CO₂) under otherwise identical conditions was on average 75% of that achieved by steam, but their BET surfaces are almost the same. The proper activation greatly improved the aqueous adsorption of raw char, especially for small molecular adsorbates, for example, phenol from 6 to 51 mg/g. With increasing burnoff, phenol adsorption exhibited a first-stage linear increase followed by a rapid drop after 30% burnoff. Similarly, iodine adsorption first increased linearly, but it held as the burnoff exceeded 40%, which implied that the reduction of iodine adsorption due to decreasing micro-pores was partially made up by increasing mesopores. Both raw chars and activated chars showed appreciable adsorption capacity of methylene-blue comparable with that of commercial carbons. Thus, tire-derived activated carbons can be used as an excellent mesoporous adsorbent for larger molecular species.     

基于排队论的城市垃圾箱最佳间距研究

针对城市垃圾箱最佳间距的研究不够精细的现状,本文通过建立排队论模型得到了可供不同城市参考的城市垃圾箱最佳间距参数表。通过对部分城市街道的垃圾箱摆放间距情况进行实地调查,运用层次分析法将影响垃圾箱间距分布的多重因素转化为单因素;建立了基于指数分布的数学模型,利用排队论分析单因素状态下的垃圾箱间距分布,得到了求解城市垃圾箱最佳间距的一般方法。     

Enhanced degradation of azo dye alizarin yellow R in a combined process of iron–carbon microelectrolysis and aerobic bio-contact oxidation

Purpose

With the aim of enhanced degradation of azo dye alizarin yellow R (AY) and further removal of the low-strength recalcitrant matter (LsRM) of the secondary effluent as much as possible, our research focused on the combination of aerobic bio-contact oxidation (ABO) with iron/carbon microelectrolysis (ICME) process.

Materials and methods

The combined ABO (with effective volume of 2.4?l) and ICME (with effectively volume of 0.4?l) process were studied with relatively short hydraulic retention time (HRT) of 4 or 6?h.

Results

At the HRT of 6?h with the reflux ratio of 1 and 2, the AY degradation efficiency in the final effluent was >96.5%, and the total organic carbon (TOC) removal efficiency were 69.86% and 79.44%, respectively. At the HRT of 4?h and the reflux ratio of 2, TOC removal efficiency and AY degradation efficiency were 73.94% and 94.89%, respectively. The ICME process obviously enhanced the total AY removal and the generated micromolecule acids and aldehydes then that wastewater backflow to the ABO where they were further biodegraded.

Conclusion

The present research might provide the potential options for the advanced treatment azo dyes wastewater with short HRT and acceptable running costs.     

超声波促进城市生活污泥缺氧/好氧消化的研究

本研究将超声波预处理引入城市生活污泥缺氧/好氧消化工艺中,自主设计了容积为30 L的生活污泥超声波-缺氧/好氧消化中试系统并用以实验研究。超声波预处理的参数为超声频率28 kHz,声能密度0.15 W/mL,超声时间10 min,超声间隔12 h,污泥超声比例30%。结果表明,引入超声预处理后,缩短了污泥的稳定时间,提高了污泥的消化效率。污泥消化10 d就已经达到了稳定标准,比未引入超声预处理时缩短了12 d,而MLVSS最大去除率提高了11%,达到了55.10%。超声波的引入,对污泥缺氧/好氧消化系统中污泥上清液溶解性COD（SCOD）的变化趋势影响比较明显,而对上清液的pH、氨氮和TP的变化趋势没有明显影响。     

复合型絮凝剂处理景观水体

利用以生物絮凝剂(1 g/L MBF-28)与化学絮凝剂(5 g/L PAC)复配后的复合絮凝剂CBF28C处理景观水体,考虑了复配比、投加量、pH和投加顺序对处理景观水的影响。实验结果表明:对于反应体系为100 mL景观水体,当MBF-28与PAC溶液复配体积比为3∶1,反应体系pH为7.0,1 mL 1%CaCl2作助凝剂,1.5 mL CBF28C时,其絮凝效果最好,其COD,色度,TN,TP的去除率分别为90.7%,54.1%、46.6%和51.5%。最佳水力条件为:快速320 r/min,快搅时间45 s,慢速80 r/min,慢搅时间100 s。并且得出了前10 min内絮凝率的反应关系方程式。