Removal of ammonium ion from water by Na-rich birnessite: Performance and mechanisms

Na-rich birnessite (NRB) was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion (NH₄⁺) from aqueous solution. In order to demonstrate the adsorption performance of the synthesized material, the effects of contact time, pH, initial ammonium ion concentration, and temperature were investigated. Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model. The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated. The monolayer adsorption capacity of the adsorbent, as obtained from the Langmuir isotherm, was 22.61 mg NH₄⁺-N/g at 283 K. Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process. Our data revealed that the higher NH₄⁺ adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction. Particularly, the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion. The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system.     

静电活性炭净水器的实验研究

静电活性炭净水器是将静电杀菌技术与活性炭吸附过滤技术相结合，解决单一活性炭净水器滋生细菌及ＮＯ２＾－－Ｎ超标等问题，实验结果表明，电流密度为４．９２ｍＡ／ｃｍ＾２，产水率为１Ｌ／ｍｉｎ时，该净水器能起到杀菌抑菌的作用，出水ＮＯ３＾－－Ｎ〈０．０３ｍｇ／Ｌ，而且不会改变活性炭固有的吸附容量和吸附效果。     

工业雷管意外起爆的防范研究

工业雷管在生产、贮运、使用过程中存在意外发火或爆炸事故。为了防止这种突然事件和避免带来的伤害与损失，笔者就可能导致意外起爆的各种原因进行了分析，提出了各种相应的防范措施和意见     

粉料无尘装车技术及其在电除尘器、大布袋除尘器输灰系统中的应用

传统电除尘器、大布袋除尘器输灰系统存在工艺繁杂、能耗大、输送速度慢、系统难于维护及二次扬尘问题,电除尘器、大布袋除尘器输灰系统采用粉料无尘装车技术可有效简化工艺、提高生产速度和系统运行、维护可靠性,很大程度减少能耗并彻底根除二次扬尘。     

静电增强纤维层过滤技术的研究

对静电增强纤维层过滤进行理论及实验研究。得出纤维层在非稳态状态下,考虑三种作用机理时的效率式,并利用模型系统进行实验研究,对各种影响因素加以分析     

高电阻率收尘极板的实验研究

用电阻率较高的非金属材料制作电收尘器的收尘极板收尘,对于比电阻低于10~4Ω·cm的烟尘,能有效地克服积尘的跳跃式二次飞扬。对于比电阻为10~8Ω·cm左右的氧化铝粉尘,在工业现场实验,收尘效率达98.5％;对于比电阻为10~(13)Ω·cm左右的莹石粉尘,采用比电阻为10~(10)Ω·cm左右的混凝土极板,实验室实验,电晕电流正常,未观察到反电晕现象,推断存在“受抑制”的尘层间隙放电。     

Magnetophoretic separation of Chlorella sp.: Role of cationic polymer binder

Cationic polyelectrolyte promoted effective attachment of iron oxide nanoparticles (IONPs) onto microalgal cells through electrostatic attraction. Poly(diallyldimethylammonium chloride) (PDDA) and chitosan (ChiL), both are cationic polymer, are feasible to act as binding agent to promote rapid magnetophoretic separation of Chlorella sp. through low gradient magnetic separation (LGMS) with field gradient ▿B less than 80 T/m in real time. Cell separation efficiency up to 98% for the case of PDDA and 99% for the case of ChiL can be achieved in 6 min when 3 × 10⁷ cells/mL Chlorella sp. are exposed to 300 mg/L surface functionalized-IONPs (SF-IONPs). Different polyelectrolytes do not give significant effect on cell separation efficiency as long as the particle attachment occurred. However, the PDDA is more preferable as the binder for all type of microalgae medium than the chitosan (ChiL) since it is not pH dependent. SF-IONPs coated with PDDA guarantee the cell separation performance for all pH range of cell medium, with 98.21 ± 0.40% at pH 8.84. On the other hand, the ChiL performance will be affected by the cell medium pH, with only 22.93 ± 31.03% biomass recovery at pH 9.25.     

运煤系统粉尘综合治理方案评估

通过对运煤系统的除尘系统的设计及评估,将3种除尘过程进行详细的比较分析,得出,布袋除尘器方案技术合理,初投资最低,运行费用适中。因此推荐布袋除尘器作为本工程输煤系统除尘方案。     

Triboelectric charging behavior of wood particles during pellet handling processes

Electrostatic charges accumulated on wood particles through triboelectrification during their transportation and handling processes can cause hazardous electrical discharge which may further trigger dust explosion. In this work, tribo-charging behavior of different kinds of wood particles was investigated by a vibrating plate charging method. It was found that reduction in the work function difference between contact bodies might contribute to the reduction of tribo-charge generation, while the reduction of electrical resistivity of wood pellets could effectively accelerate the charge dissipation. As the particle size decreases, accumulated charges increase significantly. In contrast, higher moisture content of wood particles leads to lower charge accumulation due to an accelerated charge dissipation rate. Tribo-charging behaviors of white pellets, torrefied pellet, steam treated pellets and dark pellets have also been investigated. Compared to the white pellets, they all have shown a reduction on charge accumulation to some extent. However, results suggested that all of them have nearly equivalent tribo-charge density as coal and wheat grains used as references in this study.