A study of the chemical forms or species of manganese found in coal fly ash and soil

The chemical speciation of manganese of environmental and toxicological interest was undertaken in coal fly ash and soil. Hard coal used in combustion creates considerable quantities of waste ash. The greatest quantities of industrial ashes are stored in the form of waste-heaps, which create a serious problem as the source of inorganic pollution. It is necessary to identify physical and chemical properties of ash, especially when analyzing the pollution of soil by trace metals, which are potentially mobile in environment. In this work, a new analytical method has been developed and used successfully for identification and determination of chemical forms of manganese in coal fly ash and soil. The basic chemical forms of metals contained in the environmental samples (fly ash and soil) can be described by using sequential extraction method. To identify Mn ions, the UV-VIS spectrophotometric method was used by means of comparative analysis of spectrophotometric spectra of appropriate Mn ions in the standard solutions and solutions obtained after extraction. The concentration of manganese in all solutions was determined by the Flame Atomic Absorption method. The experimental approach and analytical method developed in this study appear adequate for this purpose and can therefore be used for similar research.     

Transformation of South African coal fly ash into ZSM-5 zeolite and its application as an MTO catalyst

This study presents a way of using South African coal fly ash by extracting metals such as Al and Fe with concentrated sulphuric acid, and then using the solid residue as a feedstock for the synthesis of ZSM-5 zeolite. The percentage of aluminium and iron oxides decreased from 28.0 ± 0.2% and 5.0 ± 0.1% in coal fly ash to 24.6 ± 0.1% and 1.6 ± 0.01% in the acid treated coal fly ash respectively. The fly ash-based zeolite ZSM-5 sample synthesised from the solid residue after extraction of Al and Fe, contained 62% of ZSM-5 zeolite pure phase with a number of Brønsted acid site density of 0.61 mmol per g_zeolite.By properly treating the as-prepared coal fly ash-based ZSM-5 zeolite, an active and selective methanol-to-olefins acid catalyst could be designed, leading to full methanol conversion during 15 h on stream. The optimised catalyst exhibited a cumulative methanol conversion capacity of 71 g(MeOH_converted)/g(catalyst) and a light olefin productivity of 21 g(C₂₌–C₄₌)/g(catalyst).     

Components Analysis of Biochar Based on Near Infrared Spectroscopy Technology

This study aims to establish a rapid quantitative analysis method for biochar based on near infrared spectroscopy (NIRS) technology. Near infrared spectra of 163 samples in the 10000–3800 cm^–1 (1000–2632 nm) range were collected, and the contents of fixed carbon (FC), volatile matter (VM) and ash of samples were also analyzed. A partial least square (PLS) model for FC, VM and Ash was established after the model spectral ranges were optimized, the optimal factors were determined, and the raw spectra were pretreated by multiple scatter correction and second derivative (MSC + SD) method. Finally, the prediction performance of predictive model was evaluated. The results showed that the PLS model had a good prediction ability, and the predicted coefficient R²_p of actual values vs prediction values for FC, VM and ash were 0.9423, 0.9517 and 0.9265, respectively. Root mean square error of prediction (RMSEP) was 0.1074, 0.1201 and 0.1243, and ratios of prediction to deviation (RPD) were 3.51, 4.28 and 2.03, respectively. The PLS model had good accuracy and precision for both of FC and VM, and could be used as a quantitative method for FC and VM contents analysis. Nevertheless, PLS model need to improve the precision for Ash analysis according to RPD value. This method provides a fast and effective technical means for the quantitative analysis of biochar components.     

Rapid qualitative and quantitative evaluation of deer antler (Cervus elaphus) using near-infrared reflectance spectroscopy

Near-infrared (NIR) spectroscopy has been applied for both the qualitative and quantitative evaluation of the velvet deer antler. The most important parameters of determining the quality of velvet antler are the habitat (the country of origin) and ash content. Conventionally, the habitat is determined by examining the appearance of samples (by human eye), which lacks objectivity. Ash content is measured by an ignition method (measurement ash residue), however, it is too slow (4–5 h) to be used for rapid at-site measurement. Velvet antlers from three different habitats (China, New Zealand, and Russia), albeit the same species of Cervus elaphus, were evaluated in this paper. Soft independence modeling of class analogies (SIMCA) and partial least squares (PLS) were used for classification of habitat and determination of ash content. The habitat was successfully identified with over 80% accuracy, and the ash content prediction result using PLS regression showed good correlation with the reference ignition method with a standard error of prediction (SEP) of 1.264%.     

Fly compound-eye inspired inorganic nanostructures with extraordinary visible-light responses

Inorganic bio-inspired nanomaterials, which integrate the unique properties of metal oxide nanomaterials and the features of well-evolved biological structures and functions, are a novel direction towards mining the potential of existing materials to further enhance the performance of various microelectronic and energy harvesting, conversion, and storage devices, although the facile fabrication of bio-inspired materials still remains a major challenge. We noticed that some compound eyes presented extremely strong responses to light and displayed beautiful colours and patterns, which inspired us to design novel photonic materials. In this study, we fabricated fly compound-eye inspired ZnO nanomaterials in the forms of either isolated microspheres or highly-ordered coatings grown in-situ, in which the three-zone structures were similar to the anatomical structure of the biological compound eyes, including an outermost faceted microlens array, a middle rhabdom-like channel layer, and a central hollow zone. The bio-inspired nanomaterials, as we expected, presented extraordinary visible-light response behaviour and would make it possible to capture energy across a wide solar spectrum with a single semiconductor material. This study thus paves the way to further improving the performance of the current photoelectronic and energy harvesting, conversion, and storage devices.     

HRGC-LRMS测定垃圾焚烧炉布袋飞灰中的二噁英类物质

利用高分辨气相色谱-低分辨质谱(HRGC-LRMS)测定了某垃圾焚烧厂布袋飞灰中的二(口恶)英类物质,结果表明对于测定二(口恶)英类浓度相对较高的垃圾飞灰而言,采用HRGC-LRMS是一种可行的方法,回收率在74％～114％之间。该飞灰样品中以二(口恶)英为主,呋喃的含量相对较低,二(口恶)英／呋喃值为4.6,二(口恶)英类物质总量为211.7ng／g,折算到毒性当量为0.69ngI-TEQ／g。     

Transportation characteristics of gas–solid two-phase flow in a long-distance pipeline

In this study, experiments on fly ash conveying were carried out with a home-made long-distance positive-pressure pneumatic conveying system equipped with a high performance electrical capacitance tomography system to observe the transient characteristics of gas–solid two-phase flow. The experimental results indicated that solids throughput increased with increasing solids–gas ratio when the conveying pipeline was not plugged. Moreover, the optimum operating state was determined for the 1000 m long conveying pipeline with a throttle plate of 26 orifices. At this state the solids throughput was about 12.97 t/h. Additionally, the transportation pattern of fly ash gradually changed from sparse–dense flow to partial and plug flows with increasing conveying distance because of the conveying pressure loss. These experimental results provide important reference data for the development of pneumatic conveying technology.     

分光光度法研究改性粉煤灰对有机磷的吸附性能

常温下,用硫酸铝为改性剂制得改性粉煤灰,以此作为有机磷废水的吸附剂,用分光光度法分析改性粉煤灰对有机磷的吸附性能,并通过XRD对其结构进行表征。结果表明:改性时,盐灰质量比为1∶12;吸附时,改性粉煤灰用量为35g/L、溶液的pH值为8、振荡时间为30min、吸附温度为30℃时,磷的去除率可达97.0%。     

卤化物缓冲剂电弧发射光谱法测定煤灰份中的微量和痕量元素

本文研究了降低煤灰份中微量和痕量元素摄谱分析检测限的途径；考察了氯化物、氟化物、溴化物、碳酸盐、氧化物及炭粉、硫粉十七种光谱缓冲剂对谱线强度的影响。ＮａＣｌ－ＮＨ４Ｆ对谱线强度有显著增强作用，确定ＮａＣｌ∶ＮＨ４Ｆ的最佳配比为１∶２．选择钴、锡为内标，对电流、极距、曝光时间通过正交试验进行了最佳选择，对缓冲剂作用进行了讨论     

Accurate determination of naturally occurring radionuclides in Philippine coal-fired thermal power plants using inductively coupled plasma mass spectrometry and γ-spectroscopy

There is an increased interest in measuring naturally occurring radioactive materials (NORM) like coal, fly ash considering health hazards caused by naturally occurring radionuclides. This paper presents activity concentration (AC) of ²²⁶Ra, ²²⁸Ra, ²³²Th, ²³⁸U and ⁴⁰K in feed coal, bottom and fly ash samples from Philippines coal-fired thermal power plants using inductively coupled plasma mass spectrometry (ICP-MS) and high-purity germanium gamma spectroscopy (HPGe γ-spectroscopy). Coal, bottom and fly ash samples were digested using a microwave oven with a mixture of HNO₃, HClO₄ and HF. Uranium (²³⁸U) and thorium (²³²Th) ACs were also analyzed from samples using ICP-MS. A good correlation was found for the measurement of U and Th using both techniques (R² = 0.97 and 0.94 respectively). ICP-MS measurements showed the highest AC of ²³²Th and ²³⁸U in fly ash and lowest for feed coal samples. With HPGe γ-spectroscopy measurements, highest AC (in Bq kg^{− 1}) of ²²⁶Ra, ²²⁸Ra, ²²⁸Th and ⁴⁰K, were noticed in fly ash followed by bottom ash and feed coal. ICP-MS method is rapid for the measurement of uranium and thorium in comparison to γ-spectroscopy as secular equilibrium is not required. Activity concentrations of bottom and fly ash samples were found to be within the reported values worldwide and below the International Atomic Energy Agency recommended values for regulatory control.