Removal of copper (II) and phenol from aqueous solution using porous carbons derived from hydrothermal chars

The feasibility of hydrothermal char (HTC), a byproduct from biomass hydrothermal liquefaction for bio-oil production, as raw material for preparation of porous carbons was investigated in the present study. The resultant HTC-derived porous carbons were characterized and utilized as adsorbents for copper (II) and phenol removal from aqueous solution. Compared with porous carbons using pyrolytic char as precursor, the HTC-derived porous carbons exhibited unique textural features, e.g., narrow pore size distribution, high surface area and large pore size. In addition, FT-IR analysis confirmed that substantial amount of ketene groups existed on the surface of the HTC-derived porous carbons. As the adsorbents, the copper (II) adsorption onto HTC-derived carbons was strongly affected by the pH value of the solution in comparison with phenol adsorption. The carbons derived from pinewood and rice husk HTC exhibited high adsorption capacity of 83.88 and 39.30 mg/g for phenol and 25.18 and 22.62 mg/g for copper (II), respectively. The adsorption data for copper (II) and phenol onto the carbon adsorbents could be well described by Langmuir and Freundlich models. In comparison with pinewood sawdust HTC-derived carbon, the adsorption onto rice husk HTC-derived carbon preferentially followed Freundlich model due to the presence of silica on the surface.     

Extraction of 1-butanol from aqueous solutions by pervaporation

The extraction of 1-butanol from fermentation broths by pervaporation offers potential for use in biotechnology. Various membrane materials have been screened for their suitability for this process. Polydimethylsiloxane (PDMS) membranes gave the best results in terms of flux and selectivity, with large variations depending on their nature and preparation. Selectivity was further increased by including either organophilic adorbents (cyclodextrins, zeolites), or oleyl alcohol in dense PDMS membranes. The predominance of driving force (i.e. activity gradient) on pervaporation extraction performances was shown by a comparative study on different binary aqueous solutions of alcohols. Water flux remained practically constant while the alcohol flux was linearly related to its feed concentration. The conclusions obtained with binary mixtures were consistent with those obtained with two model ternary solutions; the influence of salt on 1-butanol permeability was negligible, whereas ethanol had a strong effect.     

铁炭内电解法处理酸性废水

利用铁炭内电解法处理酸性废水,研究了铁、炭、pH值、水力停留时间对此废水COD去除效果的影响。结果表明,通过铁炭内电解可使酸性废水COD去除率达83%。     

Biofilter in water and wastewater treatment

Biofilter is one of the most important separation processes that can be employed to remove organic pollutants from air, water, and wastewater. Even though, it has been used over a century, it is still difficult to explain theoretically all the biological processes occurring in a biofilter. In this paper, the fundamental of biological processes involved in the biofilter is critically reviewed together with the mathematical modeling approach. The important operating and design parameters are discussed in detail with the typical values used for different applications. The most important parameter which governs this process is the biomass attached to the medium. The relative merits of different methods adopted in the measurement of the biomass are discussed. The laboratory-and full-scale applications of the biofilter in water and wastewater treatment are also presented. Their performances in terms of specific pollutant removal are highlighted.     

电解法在废水处理中的应用及研究进展

综合分析了近年来电解法在废水处理中的应用及研究进展情况。重点阐明电解法处理难生物降解废水、电解法应用于消毒杀菌和电解法与其他方法联合处理方面 ,并同时提出了电解法废水处理技术目前存在的问题及今后发展的方向     

离子膜电解技术在废水处理中的应用研究进展

离子膜电解是电渗析和电解结合的具有综合功能特性的技术,近年来在废水处理方面的应用逐渐兴起.根据离子膜电解技术在污染治理中已取得的成果,对离子膜电解技术处理废水的原理及应用现状进行了综述,并对其存在问题及今后发展方向作了一定的探索.     

铁炭内电解处理含铬废水的工艺改进

探讨了铁炭内电解-还原沉淀工艺处理含铬废水的机理和可行性,对工艺参数进行了单因素试验,并通过正交试验确定了优化工艺参数。结果表明,进水pH值等于2.0,Cr6+的质量浓度为50 mg/L,微电解接触时间为16 min,原水与铁炭床出水混合的体积比为1:14,还原反应时间为25 min时,处理后Cr6+的去除率达到100%,与常规铁炭内电解工艺相比该工艺可以节省15%的处理成本。     

曝气对催化铁内电解法处理有机废水的作用

采用催化铁内电解法,在曝气和无曝气条件下,对有机废水的处理效果进行了比较并且分析了在不同条件下的反应机理。结果表明,若不考虑反色现象,无曝气条件下对色度的去除率达到88%,高于曝气条件下的去除率69%,在无曝气条件下色度的去除主要是由于染料分子被还原,而曝气条件下色度的去除主要是由于铁离子的絮凝作用;对于COD的去除率,曝气条件下为41%,高于无曝气条件下的22%。     

Catalytic conversion of waste biomass by hydrothermal treatment

The purpose of the work presented here is the production of liquid biofuels from wet organic waste matter in a continuous one-step catalytic process under hydrothermal conditions. The catalytic reaction of wet organic matter at near-critical water conditions (T > 300 °C, p > 22.1 MPa) is used to produce a mixture of combustible organics which can be used as liquid biofuel. In order to achieve a good product quality in a continuous one-step process, two catalysts were applied, a homogeneous potassium carbonate catalyst and a heterogeneous ZrO₂ catalyst. In addition, the reaction mixture was recirculated. The continuous flow of concentrated waste biomass feed at low flow rates and recirculation of the hot reaction mixture were the most challenging obstacles to overcome. The scale of the plant (0.1 l reactor volume) allowed for a variation of the feed, reaction temperature, and recirculation rate in order to optimise the process conditions. Still, the product quantity obtained was sufficient to perform a analytical characterisation. The experimental results confirmed the feasibility of the process. Hydrothermal treatment of waste biomass, after dewatering, resulted in a biocrude oil of high calorific value.     

The effect of hydrothermal dewatering of Pontianak tropical peat on organics in wastewater and gaseous products

This paper describes a study of the effects of hydrothermal dewatering of raw tropical peat from Pontianak, West Kalimantan-Indonesia, on the amounts of organic compounds released into wastewater and gaseous products. Hydrothermal upgrading and dewatering of the peat was carried out in a batch-type autoclave reactor at temperatures between 150 and 380 °C at a maximum pressure of 25.1 MPa for 30 min. It was found that the extent of decomposition of organics during hydrothermal dewatering depended on temperature increase.Wastewater from hydrothermal dewatering was found to contain organic carbon (TOC) ranging from 800 ppm at low temperatures, to 7504 ppm at high temperatures. A number of sugars and furans were detected in the wastewater at 250 °C, and organic acids and alcohols at all temperatures. Phenol and phenolic derivatives were observed at 250 °C, and significant amounts of CO₂, CO and H₂ were detected at all temperatures studied; CH₄ was detected only at 380 °C, but at this temperature CO₂ was no longer detected.A simplified schematic diagram of the decomposition behavior of tropical peat in the hydrothermal dewatering process is discussed with respect to the change in the concentration of organics in wastewater and gaseous products as determined by TOC, GC, GC–MS and ¹³C NMR analyses of the solids produced.     

电解阳极间接氧化法处理制药废水的研究

通过在废水中加入NaCl电解质，考察了电解阳极间接氧化法制药废水的处理效果。实验分析了废水中电解质NaCl对制药废水电解过程中CODCr、色度去除的影响，并对不同用量NaCl电解效果进行了对比。另外还用电解质Na2SO4、NaNO3作了对比实验来说明NaCl产生的电解阳极间接氧化的存在。最后对甲红霉素废水进行中试实验，结果表明，NaCl电解产生的NaClO具有极强的氧化性，促进了CODCr的去除，同时还发现，废水中氨氮的存在不利于废水CODCr的去除。     

生物酶法合成(S)-2-氨基-1-丁醇的研究

以粪产碱杆菌来源的青霉素G酰化酶为催化剂,酶法拆分苯乙酰消旋底物转化生成(S)-2-氨基-1-丁醇。通过对催化过程中加酶量、底物浓度、反应温度、pH进行优化,确定最适酶催化条件是pH 9.0,40℃,底物浓度100 mmol/L,酶量2 U/mL,反应体积80 mL。在最适反应条件下,当消旋底物转化率达40%时终止反应可获得较高的产物光学纯度(ee>99%)。     

内电解—两级生化法处理医药化工废水

介绍了应用铁屑内电解、中和混凝、兼氧、接触氧化工艺处理医药化工废水的工程实例。长期的运行结果表明，该工艺处理效果稳定、耐冲击负荷，并对工艺各处理阶段的成功之处作了总结。     

电解装置废水回收利用总结

介绍了电解装置的废水回收利用情况及从原始设计状态经过多次改造逐渐达到工艺完善和废水零排放的实施情况。     

R-2-氨基-3-甲基-1,1-二苯基-1-丁醇的合成

R-2-氨基-3-甲基-1,1-二苯基-1-丁醇是一种合成手性催化剂的重要中间体。从原料R-缬氨酸经甲酯化,苄氧羰基保护制得R-2-苄羰基氨基-3-甲基-丁酸甲酯,然后与苯基溴化镁反应制得（R）-2-苄氧羰基氨基-3-甲基-1,1-二苯基-1-丁醇。接着在5%Pd/C催化加氢下脱除苄氧羰基得到目标化合物,总收率58%。此制备方法涉及的中间体及目标化合物易于纯化,总收率高且重现性好。     

Ammonium nitrate wastewater treatment by coupled membrane electrolysis and electrodialysis

A process coupling membrane electrolysis and electrodialysis is implemented to treat ammonium nitrate wastewater. Membrane electrolysis produces ammonia and nitric acid while electrodialysis reconcentrates the depleted salt solution. Ammonia is removed continuously by in situ stripping; thus allowing gas production with a constant current efficiency (about 70%). Nitric acid up to 8 mol L^–1 is obtained. The current efficiency of acid production depends on nitric acid concentration. When this concentration varies from 1 to 8 mol L^–1 the average current efficiency is about 58%. Electrodialysis produces a rejected stream containing less than 3 × 10^–3 mol L^–1 of ammonium nitrate.     

A novel nickel/carbon catalyst for CH4 and H2 production from organic compounds dissolved in wastewater by catalytic hydrothermal gasification

A novel Ni/carbon catalyst recently developed by the authors was used to gasify organic compounds dissolved in the wastewater with TOC concentration from 0.2 to 2%. The process removes the organic compounds by gasifying them into high calorific gases like methane and hydrogen. The investigations were focused on the efficiency of the Ni/carbon catalyst in terms of carbon conversion, conversion of big organic molecules, and catalyst deactivation due to sintering. The preliminary results showed that up to 99% carbon conversion can be achieved at 360 °C, and 20 MPa. A conversion mechanism was suggested which consists of: first, decomposition of big molecules to small molecules on the metal surface, steam gasification of small molecules to produce CO and H₂ followed by CO methanation and CO shift reaction to produce CH₄ and CO₂. The catalyst was found to be highly active and stable and no sintering was observed even after 100 h of reaction time.     

内电解法处理印染废水的效果研究与分析

印染废水成分复杂、色度高、CODCr高且难降解,对环境造成较大污染。印染废水处理一般采用生化一混凝沉淀法、混凝气浮法、化学氧化及活性炭吸附法等,但这些方法存在运行费用较高、不易管理等缺点。内电解的基本原理是利用铁屑中的铁和炭组分构成微小原电池的正极和负极,以充入的废水为电解质溶液,发生氧化-还原反应,形成原电池。利用内电解对印染废水进行预处理,脱色率可达75％。90％,CODCr去除率达55％左右。另外还可提高废水的可生化性,废水的BOD5/CODCr值从原来的0.23提高到0．57,为后续生化处理和处理后达标排放奠定了基础,且运行成本低,易于管理。     

Ti/SnO_2电极隔膜电解处理氨氮废水技术研究

分别以平板Ti/SnO_2网状电极和石墨为阳极和阴极,制作隔膜和无隔膜电解反应器并对比处理500mg/L自配氨氮溶液。在处理水量为3.6 L,电流密度为10 m A/cm2,有效阳极面积为1 440 cm~2,电流为0.8 A,反应时间70 min条件下,出水氨氮分别为74、222 mg/L,去除率分别为85.2%、55.6%;当两种反应器吨水电耗均为10.5k W·h时,出水氨氮分别为74、153 mg/L,去除率分别为85.2%、69.4%。在出水氨氮相同时,隔膜电解反应器在吨水电耗、电流效率以及反应速率方面均优于无隔膜电解反应器。     

Characterization and application of chars produced from pinewood pyrolysis and hydrothermal treatment

Two types of pinewood chars, hydrothermal char (H300) and pyrolytic char (P700) from biomass-to-energy conversion were characterized and used as adsorbent for the copper removal from aqueous solution. The result showed that the pinewood underwent a deeper carbonization during pyrolysis process and more activated sites available and stable carbon-oxygen complex existed after hydrothermal treatment. Comparing with raw pinewood, hydrothermal treatment increased 95% total oxygen-containing groups (carboxylic, lactone and phenolic group) while 56% oxygen-containing groups decreased after pyrolysis process. SEM analysis indicated that both hydrothermal and pyrolytic processes developed rough surface with new cavities on the chars, and the BET surface area were 21 and 29 m²/g for H300 and P700, respectively. Although H300 had lower surface area, its adsorption capacity for copper was much higher than P700 since ion-exchange reaction was the predominant removal mechanism by H300, while physical adsorption dominated by P700. The adsorption data could be well described by Langmuir isotherm model for copper onto both H300 and P700.