利用轻度炭化的玉米秸秆炭脱除沼气中硫化氢的研究

利用专利方法制得轻度炭化的玉米秸秆生物炭,采用电子扫描电镜观察玉米秸秆生物炭的微观结构,利用傅里叶变换红外光谱仪分析生物炭的表面性质。研究结果表明:生物炭较好地保持了玉米秸秆原有的生物结构;生物炭含有大量的木质素、纤维素和少量的未被酸解的半纤维素;碱改性的生物炭主要含有纤维素和碱不溶的木质素,碱处理可改变碱改性生物炭的有机构成和微观结构。采用固定床吸附装置研究了生物炭对沼气中硫化氢的脱除效果,研究发现,水洗炭的脱硫效果较好,高p H值有利于碱改性生物炭对硫化氢的吸附。生物炭对硫化氢的吸附动力学行为可用Bangham速率方程进行描述。     

饮用水源地水中有机污染钧质的检测方法和处理工艺

介绍饮用水源地水中含有的有机污染物的检测方法,主要是气相色谱、液相色谱、离子色谱和质谱的联用技术。对水体中含有的有机污染物的处理工艺,尤其是一些新型方法：活性炭吸附,臭氧氧化,膜处理和树脂吸附等进行详细的阐述,并指出检测和处理工艺未来的发展趋势。     

饮用水源地水中有机污染物质的检测方法和处理工艺

介绍饮用水源地水中含有的有机污染物的检测方法,主要是气相色谱、液相色谱、离子色谱和质谱的联用技术。对水体中含有的有机污染物的处理工艺,尤其是一些新型方法:活性炭吸附,臭氧氧化,膜处理和树脂吸附等进行详细的阐述,并指出检测和处理工艺未来的发展趋势。     

生物炭的制备及其对氮肥吸附效果的研究

以玉米秸秆为原材料,分别在350、400、450℃下炭化3 h制备玉米秸秆生物炭(分别命名为B350、B400、B450),利用X射线衍射仪、扫描电镜仪、比表面积及孔径分布仪、红外光谱仪等对材料进行表征,确定材料的相关性能,并探讨其与氮肥吸附的相关性。以平衡实验法研究了溶液pH对生物炭吸附氨氮的影响。实验结果表明:玉米秸秆生物炭B350、B400、B450对氨氮的吸附过程均遵循二级吸附动力学模型,且采用Langmuir方程能更好地描述吸附等温线模型;玉米秸秆生物炭对氨氮的饱和吸附量按从大到小依次为B400、B350、B450,且均为有利吸附;玉米秸秆生物炭对氨氮吸附的最佳pH为8～12。     

炭化时间对长、短绒棉基生物炭性能的影响

为了实现新疆棉秆资源的循环利用,将棉秆制备成了对南疆沙化土壤具有改良作用的生物炭。文章以棉花秸秆为原料制备棉秆基生物炭,研究炭化时间对长绒棉基生物炭和短绒棉基生物炭的产率、含水率、pH值、碘吸附值和持水能力的影响。研究结果表明:长绒棉基生物炭的产率和pH值比短绒棉基生物炭大,含水率和碘吸附值却比短绒棉基生物炭小;当炭化时间为4 h时,两种生物炭的产率相差不大,短绒棉基生物炭的pH值比长绒棉基生物炭小,短绒棉基生物炭的持水能力更强。因此,短绒棉基生物炭有望解决南疆沙化土壤持水能力差的问题。     

富营养化水体底泥污染控制及生物修复技术探讨

污染物通过大气沉降、废水排放、雨水淋溶与冲刷进入水体,最后沉积到底泥中并逐渐富集,使底泥受到严重污染。同时,底泥表层营养物、重金属和有机污染物等含量较高,使污染物有向水体释放的趋势,对水体质量及水生生态系统可造成威胁。在对底泥现状分析的基础上,结合目前国内外几种主要污染底泥控制方法和技术的研究．提出底泥的污控技术及应采取的生物修复方法。     

松子壳基活性炭光催化剂的制备及其催化性能研究

为了提高TiO_2光催化剂对水体有机污染物的降解能力,将松子壳基活性炭作为载体负载TiO_2,研究载体比表面积、载体与TiO_2的复合比例以及煅烧温度对复合光催化剂降解水体有机污染物亚甲基蓝的影响。通过BET,XRD,FTIR和SEM分析方法对复合光催化剂的比表面积、晶体结构、有机官能团和表面形貌进行了表征。研究结果表明:适当的增加载体的比表面积,有利于Ti O2的负载和复合光催化剂催化活性的提高;当活化水量为1.5 mL/min时,在充分的水蒸气活化反应下,松子壳炭可制备成比表面积为634.65 m~2/g的活性炭,使其负载TiO_2后具有较好的亚甲基蓝吸附作用和光降解作用;当TiO_2与活性炭的质量比为0.8∶1时,复合光催化剂的催化效果较好;当煅烧温度为450℃时,复合光催化剂具有较优的催化效果,降解率可达77.10%。     

污泥与不同生物质共热解制备生物炭及生物炭的土地应用

文章以乙酸钾为催化剂,在城市污泥中分别添加花生壳、玉米杆、玉米芯、稻草,采用间歇式反应釜在400℃下制备多种污泥-生物质生物炭,考察不同种类生物质的添加对生物炭产率及性能的影响,并对生物炭进行表征和分析。研究结果表明:与污泥生物炭相比,不同种类的污泥-生物质生物炭的H/C均减小,芳香性均增大;与污泥生物炭相比,不同种类的污泥-生物质生物炭的比表面积和总孔体积均增大,平均孔径均减小,其中,污泥-玉米杆生物炭的BET比表面积最大,为26.062 m~2/g;与污泥生物炭相比,不同种类的污泥-生物质生物炭的碘吸附性能均有所提高,其中,污泥-玉米芯生物炭的碘吸附值最大,为438.49 mg/g;污泥-生物质生物炭呈碱性并含有一定量的速效氮、速效磷、有机质等营养物质,污泥-生物质生物炭的重金属含量(Zn除外)均远低于农业用地标准值,有作为土壤改良剂或肥料缓释载体的应用前景。     

腐植酸对有毒有机物污染土壤的修复作用

正进入土壤中的有机污染物有天然有机污染物和人工合成有机污染物两种,前者主要是在自然条件下发生化学反应或生物代谢过程中产生的,后者主要是由于人类的生产和生活活动产生的。工业的迅速发展在一方面随之产生了大量的有机工业废水,这些废水直接或间接地对水体周围的土壤造成污染。生活中洗涤剂的使用以及农业生产活动中有机农药、地膜的使用使有机污染物残留在土壤中,造成土壤有机物污染。有机污染物会对生态环境产生有害影     

生物炭负载硫化纳米零价铁活化过硫酸盐降解酸性大红GR的研究

麻黄草具有良好的比表面积和丰富的官能团,已被证实其产物具有优秀的吸附性能.纳米零价铁作为一种强反应性的过渡金属粒子,可以高效活化过硫酸盐并降解污染物.研究采用麻黄草作为原材料制备生物炭,负载硫化纳米零价铁活化过硫酸盐降解酸性大红GR.通过批次试验探究炭的烧制温度、铁的负载比、硫铁比、硫化时间、材料投加量、PS投加量、p...     

A review on the utilization of fly ash

Fly ash, generated during the combustion of coal for energy production, is an industrial by-product which is recognized as an environmental pollutant. Because of the environmental problems presented by the fly ash, considerable research has been undertaken on the subject worldwide. In this paper, the utilization of fly ash in construction, as a low-cost adsorbent for the removal of organic compounds, flue gas and metals, light weight aggregate, mine back fill, road sub-base, and zeolite synthesis is discussed. A considerable amount of research has been conducted using fly ash for adsorption of NO_x, SO_x, organic compounds, and mercury in air, dyes and other organic compounds in waters. It is found that fly ash is a promising adsorbent for the removal of various pollutants. The adsorption capacity of fly ash may be increased after chemical and physical activation. It was also found that fly ash has good potential for use in the construction industry. The conversion of fly ash into zeolites has many applications such as ion exchange, molecular sieves, and adsorbents. Converting fly ash into zeolites not only alleviates the disposal problem but also converts a waste material into a marketable commodity. Investigations also revealed that the unburned carbon component in fly ash plays an important role in its adsorption capacity. Future research in these areas is also discussed.     

生物炭基材料在生物柴油制备中的研究进展

不同种类的生物质原料可通过热转化的方式制备生物炭,由于其独特的特性被广泛应用于不同的研究领域。近期,随着生物炭合成方法的大规模涌现,生物炭及生物炭基材料相关的研究广受关注。总结了生物炭基催化剂在生物柴油制备（酯交换/酯化反应）过程中的研究现状,简要描述了生物炭催化剂的设计和合成方法,并总结了生物炭催化剂在制备生物柴油中的应用,最后归纳了生物炭基催化剂在生物柴油制备中存在的问题,对今后的研究重点及前景做出展望,以期为将来低成本生物炭基催化剂的制备以及生物柴油合成的研究和发展提供指导建议。     

改性西瓜皮生物炭对废水中Pb2+的吸附研究

以西瓜皮为原料制备生物炭（WM）吸附水中的Zn²⁺,再将吸附后的生物炭进行二次热解,制得WM-Zn并用于吸附水中的Pb²⁺。研究表明,WM-Zn对Pb²⁺ 的吸附容量（163.84 mg/g）高于WM的吸附容量（87.64 mg/g）。利用X射线光电子能谱（XPS）、傅里叶变换红外光谱（FTIR）、元素分析（EA）、X射线衍射（XRD）、吸附比表面测试法（BET）和Zeta电位对生物炭进行了表征,发现WM-Zn表面孔结构的扩大和官能团的增多均有助于Pb²⁺ 的去除,WM-Zn对Pb²⁺ 的吸附可归结为官能团络合、静电吸附、物理吸附和沉淀作用。此外,WM吸附Zn²⁺ 和WM-Zn吸附Pb²⁺ 均符合Langmuir等温吸附模型和拟二级动力学模型,表明吸附过程是以单分子层吸附为主的化学吸附。在吸附-解吸循环实验中,WM-Zn在第6次循环中吸附量可达到87.36 mg/g,表明WM-Zn吸附具有良好的可重复性。     

燃煤烟气中汞吸附的研究综述

概述了燃煤烟气中汞的吸附特性,综述了活性炭、飞灰和其它吸附剂对汞的吸附机理和影响因素,探讨了汞的吸附模型。指出活性炭对汞的脱除效率可达到90%以上,但成本高,飞灰吸附成本虽然低但脱除效率有限,其它吸附剂研究尚处于初级阶段,因此寻找廉价高效的吸附剂十分必要,同时开发烟气中污染物的联合脱除技术是研究方向。     

Enhanced oxygen evolution reaction kinetics through biochar-based nickel-iron phosphides nanocages in water electrolysis for hydrogen production

Highly-efficient and stable non-noble metal electrocatalysts for overcoming the sluggish kinetics of oxygen evolution reaction (OER) is urgent for water electrolysis. Biomass-derived biochar has been considered as promising carbon material because of its advantages such as low-cost, renewable, simple preparation, rich structure, and easy to obtain heteroatom by in-situ doping. Herein, Ni₂P–Fe₂P bimetallic phosphide spherical nanocages encapsulated in N/P-doped pine needles biochar is prepared via a simple two-step pyrolysis method. Benefiting from the maximum synergistic effects of bimetallic phosphide and biochar, high conductivity of biochar encapsulation, highly exposed active sites of Ni₂P–Fe₂P spherical nanocages, rapid mass transfer in porous channels with large specific surface area, and the promotion in adsorption of reaction intermediates by high-level heteroatom doping, the (Ni_0.75Fe_0.25)₂P@NP/C demonstrates excellent OER activity with an overpotential of 250 mV and a Tafel slope of 48 mV/dec at 10 mA/cm² in 1 M KOH. Also it exhibits a long-term durability in 10 h electrolysis and its activity even improves during the electrocatalytic process. The present work provides a favorable strategy for the inexpensive synthesis of biochar-based transition metal electrocatalysts toward OER, and improves the water electrolysis for hydrogen production.     

Influence of pyrolysis conditions on nitrogen speciation in a biochar ‘preparation-application’ process

To investigate biochar nitrogen conversion in a ‘preparation-application’ system and the response of its transportation in plants, biochar samples were produced from rice straw at different pyrolysis temperatures (400 °C and 800 °C) and atmospheres (N₂ and CO₂). Subsequently, biochar was synthesized under CO₂ atmosphere to explore its nitrogen nutrient characteristics and further improve the chemical and physical properties of soil. Nitrogen speciation of the biochar and plant root samples were evaluated by X-ray photoelectron spectroscopy. Research has shown that organic nitrogen such as protein-N, free amino acid-N, and alkaloid-N in rice straw is converted into organic (nitrile-N, pyridine-N, amino-N, and pyrrole-N) and inorganic (NH₄⁺-N, NO₂^?-N, and NO₃^?-N) species in biochar during the biomass pyrolysis process. In turn, biochar nitrogen is transported to plants as protein-N, free amino acid-N, alkaloid-N, NH₄⁺-N, NO₂^?-N, and NO₃^?-N. Comprehensive consideration of the biochar quality and preparation cost indicated the lower pyrolysis temperature (400 °C) under CO₂ atmosphere as the best conditions for biochar preparation.     

Physicochemical and structural characterization of biochar derived from the pyrolysis of biosolids,cattle manure and spent coffee grounds

In the framework of circular economy, the need of new feedstock materials for the production of alternative new products is of high priority. Biowastes such as manure, sewage sludge (biosolids, BS) and food-waste are used as raw materials for the production of biochar. The present study aims at characterizing biochars produced from three distinct biowastes (i) manure from cattle waste (manure-derived biochar; MDB), (ii) biosolids (BS) from a conventional Urban Wastewater Treatment Plant (UWTP) (biosolids-derived biochar; BDB), and (iii) spent coffee grounds (SCG)-derived biochar (SCGDB). Samples were slowly pyrolyzed in a small-scale kiln with a capacity of 20–24 kg. The samples were heated under nitrogen atmosphere at approximately 6–7 °C min⁻¹ up to the desired temperature (550 °C) and held for 1.5h. The physicochemical characterization of biochars showed the production of alkaline materials with similarities and variations in their characteristics, which depend to the type of feedstock used. The surface area of the raw materials was considerably low (<0.1 m²/g) and increased after pyrolysis to 14.03 m²/g, 3.98 m²/g and 1.53 m²/g for MDB, BDB and SCGDB, respectively. The high %C content, the low H/C ratio and the FTIR adsorption peaks revealed high aromaticity, polymerization and carbonization of the biochars and the presence of several functional groups. These, are some of the biochar properties which could lead to different sorption mechanisms of organic and inorganic contaminants. Also, they presented good stability in soil, which enables to be used as soil amendment and C sequestration mechanism. Finally, the produced biochars showed promising properties for environmental applications.     

Roles of AAEMs in catalytic reforming of biomass pyrolysis tar and coke accumulation characteristics over biochar surface for H2 production

Coke formation is a significant challenge in catalytic tar reforming. AAEMs are essential in the conversion and decomposition of tar catalyzed by biochar. In this paper, four biochar catalysts with different K and Ca contents were prepared by acid washing and loading, and the coke accumulation characteristics in catalytic tar reforming at 650 °C were investigated using a single-stage reaction system. The gas-liquid-solid products were characterized by GC-MS, Raman, N₂ adsorption, FTIR and TG. The results suggest that K-loaded biochar has a maximum tar reforming capacity of 94.9%, while H-form biochar has a tar removal efficiency of only 27.8%. The micropore area in biochar is considerably reduced and the average pore size is increased after coke deposition. While K-loaded biochar retains the highest micropore area, it also exhibits a smaller increase in average pore size. The loading of K/Ca affects the growth structure of the coke, resulting in an increased number of O-containing structures in it. The coke on the Raw biochar surface is mainly small aromatic ring structures and aliphatic structures, thus increasing the intensity of the vibrational peaks corresponding to aromatic = C–H and aliphatic C–H on it. The coke on K-loaded biochar has a large proportion of aliphatic structures, which also contributes to the reduced graphitization of it after reforming. The AAEMs-free biochar surface preferentially removes tar components carrying O-containing groups. K-loaded biochar preferentially catalyzes the reforming of mono-aromatic ring components in tar. Ca-loaded biochar preferentially removes the mono-aromatic ring components, while being less selective for the removal of tar components containing hydroxyl groups and polyaromatic ring components. The loading of K/Ca promotes the dehydrogenation of the tar fraction during reforming, while only K catalyzes the deoxygenation of tar components. H-form biochar has no appreciable catalytic activity on CH₄ cracking. AAEMs have a catalytic activity on CH₄ cracking. K is particularly effective in improving tar conversion and hydrogen production of biochar.     

Borate particulate photocatalysts for photocatalytic applications: A review

Borate is a kind of wide-bandgap semiconducting material with rich structure and variety, which is usually used in optical properties research. Its unique crystal structure has essential research value for expanding the applications of photocatalysis. This review summarizes the recent research progress of borate photocatalysis, including novel borate photocatalyst, borate-based composite, and borate glass photocatalyst. Furthermore, the energy and environmental photocatalysis applications of borate photocatalysts are discussed, such as overall water splitting reaction, water decomposition to generate hydrogen or oxygen, degradation of pollutants, and others. The strategy of the combination of theoretical calculation and experiment to explore new borate photocatalysts was also introduced. Finally, some developing directions and challenges in borate photocatalytic materials are summarized.     

鸽粪基生物炭对土壤重金属形态的影响

基于鸽粪基生物炭的优良特性,进行模拟重金属污染土壤修复试验,研究了其对Cu、Zn、Pb、Cd的作用效果及土壤中赋存形态转化的影响.结果表明:鸽粪基生物炭中的CO_3^2-及OH-可与溶液中的Pb反应产生Pb的碳酸盐和氢氧化物沉淀;在重金属复合污染土壤中添加生物炭后,生物有效性最强的可交换态Cu、Zn、Pb、Cd含量分别降低98.48%、61.79%、89.15%和32.76%.生物炭中的灰分使土壤pH值显著升高(2.5~3.13),从而增加了碳酸盐结合态含量;而土壤有机质含量的升高(37.75%~178.43%)直接导致有机结合态含量增加;和500℃生物炭相比,400℃生物炭有机质含量更高,灰分含量更低.本研究的结果可以为鸽粪基生物炭在重金属复合污染土壤修复中的应用提供一定的理论基础,也为鸽粪固废处理开拓了新的思路.