Research on Thermodynamic Characteristics of the Saturated Flue Gas Waste Heat Recovery to Reduce Turbine Extraction Steam.

The saturated flue gas is difficult to recover and use as low-grade waste heat in a coal-fired power plant. The absorption heat pump is important equipment for recovering low-grade waste heat. In this article, the saturated flue gas waste heat is recovered to reduce the turbine extraction steam of low-pressure heaters. The simulation system is built, and the operational characteristics are analyzed. The feasibility of saturated flue gas waste heat recovered is verified by the absorption heat pump to heat the boiler feedwater. The results show that generator pressure and throttle pressure have significant influence on the operational performance of the absorption heat pump. There is the risk of solution crystallization with the high-concentration dehumidification solution. The equivalent enthalpy drop of the extraction steam is lower in the higher number of heater stages, representing the weaker electricity generation capacity. The waste heat temperature of saturated flue gas can be raised by 30-40 °C, which is used as the low-grade heat source for the absorption heat pump. The feedwater of low-pressure heaters is heated by the absorption heat pump, and its temperature ranges from 59.2 to 83.8 °C. The simulation system can efficiently recover the waste heat of saturated flue gas up to 9.99 MW and achieve additional electricity generation up to 0.56 MW in the coal-fired power plant.

Biochar Modified by Nano-manganese Dioxide as Adsorbent and Oxidant for Oxytetracycline.

Biochar has limited capacity to adsorb oxytetracycline (OTC). Here we have used bamboo willow biochar (BC) as a carrier to produce nMnO2-loaded biochars (MBC) by a co-precipitation method. Their chemical compositions, morphological features, specific surface area, and surface functional groups were observed or determined. Batch experiments were conducted to assess the effects of reaction time, initial OTC concentrations, pH, salt concentrations, and natural organic matter (NOM) on OTC removal. Kinetics and isotherms indicated that OTC was mainly adsorbed via chemical interactions, and mono- and multi-layer adsorption occurred on the surface. MBC removed 19-25 times more OTC than BC, and the removal was highest at near-neutral pH, not influenced by NaCl (2, 10 mM), slighted reduced by NOM (0-20 mg L-1), and enhanced by NaHCO3 (2, 10 mM). Besides being an adsorbent, MBC acted as an oxidant and degraded 58.5% of OTC at 24 h.

Stimulated boson-peak light scattering in an aqueous suspension of spherical nanoparticles of amorphous SiO2 of similar sizes.

A forward-directed high-efficiency stimulated inelastic light scattering was detected in an aqueous suspension of spherical nanoparticles (nanoballs) of amorphous SiO2 of similar sizes (0.25 µm) with a concentration of 1013 cm-3. In the stimulated scattering spectrum, there was an intense forward directed Stokes component with a frequency shift of 0.54 cm-1, corresponding to the boson peak mode of spherical nanoparticles. The results obtained are of interest for non-equilibrium excitation of spherical particles of similar sizes of different nature present in liquids (clusters, fullerenes, spherical macromolecules, viruses, etc.).

Conversion of Oyster Shell Waste to Amendment for Immobilising Cadmium and Arsenic in Agricultural Soil.

A bulky waste, oyster shell (OS), was calcinated at 400-800°C to produce Ca-rich products (OS400-OS800) to reduce the human health risk of soil cadmium (Cd) and arsenic (As). Thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET method were used to characterize OS and its calcined products. OS and OS400-OS700 removed little Cd and As from water, whereas OS800 removed 1508 mg Cd or 514 mg As per kg of OS800 from solutions of 1032 mg Cd/L or 257 mg As/L via adsorption and precipitation. Adding OS800 at a 2% dose to a Cd- and As-contaminated soil lowered its exchangeable Cd from 60% to 27%, and reduced Cd content in the edible part of vegetable Bok Choy from 2.80 to 0.048 mg/kg and As from 1.73 to 0.47 mg/kg. Converting OS to soil amendment has the dual benefits to soil remediation and sustainable oyster aquaculture.

Stimulated Raman scattering of light in suspension of diamond microparticles in ethanol and in water.

The spectra of stimulated Raman scattering of light in ethanol and in water suspensions containing diamond microparticles with sizes 0.2-0.3 µm were investigated. An excitation radiation source was a pulsed ruby laser with a generation wavelength λ0 = 694.3 nm, a pulse duration τp ≈ 20 ns, a maximum beam energy of Emax = 0.6 J, a spectral width Δν = 0.015 cm-1, and a beam divergence 3.5·10-4 rad. For the first time, the observation of stimulated Raman scattering of light at a boson peak in suspension of diamonds microcrystals with close sizes (0.2-0.3 µm) in a liquid is reported. The corresponding spectra were recorded using a Fabry-Perot interferometer. In this case, the frequency shift of the stimulated Stokes Raman scattering depended on the size of the diamond microparticles introduced into the liquid and amounted to ~1 cm-1. In addition, stimulated Raman scattering by a fundamental optical mode with a frequency shift ν = 1331 cm-1 was observed. In this case, the Raman spectra were recorded using a small-sized spectrometer with a multi-element receiver, detecting radiation in the range of 200-1000 nm. At a sufficiently high intensity of the exciting radiation, the Stokes and anti-Stokes satellites were simultaneously present in the spectrum of stimulated Raman scattering. The obtained results on stimulated scattering of diamond microparticles in liquids are of interest for estimating the sizes of microcrystals from scattering spectra at a boson peak, as well as for creating a frequency comb of emitters based on stimulated Raman scattering with a large frequency shift.

A Soluble Humic Substance for the Simultaneous Removal of Cadmium and Arsenic from Contaminated Soils.

With abundant oxygen-containing functional groups, a humic substance (HS) has a high potential to remediate soils contaminated by heavy metals. Here, HS was first extracted from a leonardite and analyzed for its chemical compositions and spectroscopic characteristics. Then it was assessed for its ability as a washing agent to remove Cd and As from three types of soils (red soil, black soil, and fluvo-aquic soil) that were spiked with those contaminants (Cd: 40.5-49.1 mg/kg; As: 451-584 mg/kg). The operational washing conditions, including the pH and concentration of the HS, washing time and cycles, and liquid-soil ratio, were assessed for Cd and As removal efficiency. At pH 7, with an HS concentration (3672 mg C/L) higher than its critical micelle concentration and a liquid-soil ratio of 30, a single washing for 6-12 h removed 41.9 mg Cd/kg and 199.3 mg As/kg from red soil, 33.5 mg Cd/kg and 291.5 mg As/kg from black soil, and 30.4 mg Cd/kg and 325.5 mg As/kg from fluvo-aquic soil. The removal of Cd and As from the contaminated soils involved the complexation of Cd and As with the carboxyl and phenolic groups of HS. Outcomes from this research could be used to develop a tailor-made HS washing agent for the remediation of Cd- and As-contaminated soils with different properties.

Assessing the effect of pyrolysis temperature on the molecular properties and copper sorption capacity of a halophyte biochar.

The capacity of biochar to take up heavy metals from contaminated soil and water is influenced by the pyrolysis temperature. We have prepared three biochar samples from Jerusalem artichoke stalks (JAS) by pyrolysis at 300, 500 and 700 °C, denoted as JAS300, JAS500, and JAS700, respectively. A variety of synchrotron-based techniques were used to assess the effect of pyrolysis temperature on the molecular properties and copper (Cu) sorption capacity of the samples. The content of oxygen-containing functional groups in the biochar samples decreased, while that of aromatic structures and alkaline mineral components increased, with a rise in pyrolysis temperature. Scanning transmission X-ray microscopy indicated that sorbed Cu(II) was partially reduced to Cu(I), but this process was more evident with JAS300 and JAS700 than with JAS500. Carbon K-edge X-ray absorption near edge structure spectroscopy indicated that Cu(II) cations were sorbed to biochar via complexation and Cu-π bonding. With rising pyrolysis temperature, Cu(II)-complexation weakened while Cu-π bonding was enhanced. In addition, the relatively high ash content and pH of JAS500 and JAS700 facilitated Cu precipitation and the formation of langite on the surface of biochar. The results of this investigation will aid the conversion of halophyte waste to useable biochar for the effective remediation of Cu-contaminated soil and water.

Carbon-coated montmorillonite nanocomposite for the removal of chromium(VI) from aqueous solutions.

A carbon-coated montmorillonite nanocomposite (CMt), obtained by hydrothermal carbonization of montmorillonite suspension in glucose, was used to remove Cr(VI) from aqueous solutions. The distribution and speciation of Cr immobilized by CMt were assessed by transmission electron microscopy with energy-dispersive X-ray analysis, X-ray absorption near edge structure (XANES), and scanning transmission soft X-ray microscopy (STXM). The variation in the functional groups and molecular structures of CMt was also investigated. The capacity of CMt for adsorbing Cr(VI) was markedly superior to that of the parent montmorillonite, showing maximum uptake of 100 and 12.4 mg g-1 at pH 2 and 8, respectively. The Cr K-edge XANES and STXM analyses indicated that Cr(VI) was reduced to Cr(III) under both acidic and alkaline conditions, while a Cr(OH)3 precipitate and Cr(III)-acetate complex were the predominant species present on the CMt surface. The Fourier transform infrared spectroscopy and C K-edge XANES further suggested that the phenolic groups in CMt could serve as electron donors, facilitating Cr(VI) reduction. The combined results indicate that electrostatic attraction, Cr(VI) reduction, complexation, and precipitation are involved in the removal of Cr(VI) by CMt.

Pyrolysis Temperature-Dependent Changes in the Characteristics of Biochar-Borne Dissolved Organic Matter and Its Copper Binding Properties.

The dissolved organic matter (DOM) samples from biochars produced from Jerusalem artichoke stalks by pyrolysis at 300, 500, and 700 °C were characterized using a combination of spectroscopic techniques. Additionally, the binding affinities (long KM) and the complexation capacities (CL) of the DOM samples with Cu(II) were calculated to assess their Cu binding properties. The biochar-borne DOM contained mainly humic-like components (C1-C3) with a small amount of a protein-like component (C4). As the charring temperature increased, the concentrations of released DOM decreased. The low temperature biochar-borne DOM was found to have more carboxyl groups than its high temperature counterparts, and thus it had larger CL values. In contrast, the high temperature biochar-borne DOM had larger long KM values. Low temperature biochars, if applied in a large quantity, would alter copper mobility in the environment because of their high DOM contents and large copper binding capacities.

Efficacy of Traditional Chinese Medicine in patients with acute myocardial infarction suffering from diabetes mellitus.

OBJECTIVE: To investigate the ""real world"" effectiveness of Traditional Chinese Medicine (TCM) in patients with acute myocardial infarction suffering from diabetes mellitus (AMI+DM patients). METHODS: This was a retrospective cohort study. During hospitalization, the ""exposure group"" was defined as patients who had a TCM injection for ≥ 7 d. During follow-up, the definition of the exposure group was application of a Chinese patent medicine or decoction of Chinese medicine for ≥ 28 d. General information (age, sex, contact details), TCM use and endpoint events of AMI+DM patients during hospitalization and follow-up were collected. The correlation between TCM and the end-point events of AMI + DM patients was analyzed using a multiple logistic regression method. RESULTS: A total of 479 AMI + DM patients were enrolled and 345 cases were followed up. During hospitalization, TCM, age, hypertension and use of an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) were associated with cardiac death. During follow-up, TCM was associated with cardiac death. TCM was a relevant factor for a composite endpoint of re-infarction and stroke. TCM, anti-thrombotic therapy and lipid-lowering therapy were related to acute heart failure. TCM, anti-thrombotic therapy, anti-MI therapy and ACEI/ARB use exhibited a strong correlation with re-hospitalization due to cardiovascular disease. CONCLUSION: TCM reduced the prevalence of cardiac death during hospitalization, and cardiac death, a composite endpoint of re-infarction and stroke, acute heart failure and re-hospitalization due to cardiovascular disease during follow-up.

Tonifying Qi and activating blood circulation in terms of Traditional Chinese Medicine: their effects in patients with myocardial infarction.

OBJECTIVE: To investigate the effects of tonifying Qi and activating blood circulation (SQABC), a method in Traditional Chinese Medicine (TCM), on end-point events in patients with myocardial infarction (MI) in this retrospective cohort study. METHODS: Clinical data were obtained from the medical records of patients with acute MI (AMI), both during hospitalization and follow-up, and included general demographic information (age, gender, and contact information), TCM regimens used, and end-point events. RESULTS: A total of 1596 patients with AMI were enrolled to this study, but data of only 1210 cases are accessible till follow-up. We classified the patients based on the exposure levels of SQABC. When comparing the results between all exposure and non-exposure groups, significant differences were identified, both during hospitalization and follow-ups. During hospitalization, cardiac death (4.40% vs 21.55%, P < 0.05) and cardiac shock (3.04% vs 11.62%, P < 0.05) were significantly lower in the exposure group than the non-exposure group. Similarly, during the follow-up, cardiac death (12.04% vs 20.49%, P < 0.05), acute heart failure (7.27% vs 11.81%, P < 0.05), composite endpoint of reinfarction and stroke (9.11% vs 15.28%, P < 0.05), and rehospitalization due to angina (25.49% vs 34.38%, P < 0.05) were significantly lower in the exposure group than the non-exposure group. CONCLUSION: Our findings suggest that SQABC can significantly benefits the subjects in the management of high-risk AMI in them.

Leonardite-derived humic substances are great adsorbents for cadmium.

Adsorption is an important mechanism to immobilize cadmium (Cd) in soil, for which humic substances have a potential. However, commercial humic substances are either very acidic (pH = 2) or alkaline/Na+-enriched, making them less suitable for use in acid and saline soils. Here, we used leonardite to produce humic adsorbents HA (pH = 4.02), Ca-HA (pH = 10.9), and Ca-CPAM-HA (pH = 9.62) by using HCl, CaCl2, or CaCl2-polyacrylamide as a flocculant. Their elemental compositions, acidity, and spectroscopic properties were determined, and their Cd adsorption characteristics were assessed by batch kinetic and thermodynamic experiments at environmentally relevant concentrations. Further, HA was mixed with Cd-contaminated soils and incubated for a month to assess its effect on Cd immobilization. Good fitting of kinetic adsorption data into pseudo-second-order model, together with FTIR spectroscopic data, suggested the chemisorption mechanism by forming Cd(II)-carboxyl complexes. The maximum adsorption capacity derived from the Langmuir equation was 129, 114, and 110 mg Cd(II)/g for HA, Ca-HA, and Ca-CPAM-HA, respectively. These values are almost the same on carbon-normalized basis. HA reduced acetic acid extractable Cd by 31% or more. Besides their high propensity for Cd adsorption, humic adsorbents are inexpensive, safe, and beneficial to soil quality.

Humic substances as a washing agent for Cd-contaminated soils.

Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties.