Circulating interleukins concentrations and post-stroke depression: A systematic review and meta-analysis.

Interleukins may play a role in supporting the diagnosis of post-stroke depression (PSD). Here, eight databases were employed to search for studies on circulating interleukins concentrations in patients with PSD. A total of 45 studies exploring circulating interleukins in PSD and stroke patients without depression (NPSD) were included in the retrieval database, including IL-1(5), IL-1ß (10), IL-2(6), IL-6(35), IL-10(7), IL-17(5), IL-18(6). Then, the RevMan 5.4 software was used for meta-analysis. The results of the meta-analysis showed that the PSD patients have higher concentrations of IL-1, IL-4, IL-6, and lower concentrations of IL-10 than NPSD patients. Additionally, the circulating IL-1, IL-6, and IL-18 concentrations in PSD patients were significantly higher than those in NPSD patients in the acute phase; the circulating IL-6 and IL-17 concentrations in PSD patients were significantly higher than those in NPSD patients at discharge; the PSD patients have lower concentrations sin IL-2 but higher concentrations in IL-6 and IL-17 than NPSD patients at the 3rd and 6th month. Our research provides evidence that circulating interleukins may have clinical utility as a biomarker for identifying PSD.

Ratiometric fluorescence method comprising carbon dots and rhodamine 6G encapsulated in metal-organic framework microcubes for curcumin detection.

A ratiometric fluorescence method comprising carbon dots (CDs) and rhodamine 6G (Rh-6G) encapsulated in the microcubes of metal-organic framework (MOF-5) is introduced for the sensitive detection of curcumin (Cur) in condiments. CDs@MOF-5@Rh-6G, synthesized by the adsorption of Rh-6G on MOF-5 embedded with CDs, showed two distinct emission peaks at 435 and 560 nm under excitation at 335 nm, and could be used for Cur detection by ratiometric fluorescence. In the presence of Cur, the fluorescence of the CDs at 435 nm (F435) was quenched by Cur owing to internal filtering and dynamic quenching effects, whereas the emission of Rh-6G at 560 nm (F560) remained unchanged (335 nm is the excitation wavelength, 435 and 560 nm are the emission wavelengths, in which F435/F560 values are used as the output results). Under optimal conditions, a linear relationship was observed between the Cur concentration (in the range 0.1-5 µmol/L) and F435/F560 value for CDs@MOF-5@Rh-6G, with a detection limit of 15 nmol/L. Notably, the proposed method could accurately detect Cur in mustard, curry, and red pepper powders. Therefore, this study could improve the quality control of food and facilitate the development of sensitive ratiometric fluorescence probes.

Simulation of particle deposition on solar photovoltaic panels based on a new critical capture velocity criterion.

Solar energy, as a clean energy source, is becoming increasingly important in the global energy mix. However, particle deposition on the surface of photovoltaic (PV) panels can significantly reduce their power generation efficiency. In this study, the collision-deposition behaviour between silica particles and the surface of PV modules is investigated. The impact process of 13 µm silica particles on the glass surface was recorded by using a high-speed digital camera at various incident velocities and angles. A particle dynamics model was developed to predict the critical capture velocity of particles at different incident angles. It was observed that the critical capture velocity of the particles decreases as the angle of incidence increases. Subsequently, a correlation equation was established between the incident angle and the critical capture velocity, serving as the deposition criterion. Computational Fluid Dynamics (CFD) numerical simulation was employed to simulate particle deposition on PV surfaces under different wind speeds and installation tilting angles. The simulation results demonstrate that the mass of 13 µm silica particles deposited on the surface of PV panels decreases with increasing wind speed. Moreover, under identical inlet wind speeds, the particle deposition mass exhibits an initial decrease followed by a subsequent increase as the installation tilt angle of the PV panel increases. The distribution pattern of particle deposition on PV panel surfaces is diverse; however, predominantly concentrated at the mid-bottom region.

The role of NPY signaling pathway in diagnosis, prognosis and treatment of stroke.

Neuropeptide Y (NPY), an extensively distributed neurotransmitter within the central nervous system (CNS), was initially detected and isolated from the brain of a pig in 1982. By binding to its G protein-coupled receptors, NPY regulates immune responses and contributes to the pathogenesis of numerous inflammatory diseases. The hippocampus contained the maximum concentration in the CNS, with the cerebral cortex, hypothalamus, thalamus, brainstem, and cerebellum following suit. This arrangement suggests that the substance has a specific function within the CNS. More and more studies have shown that NPY is involved in the physiological and pathological mechanism of stroke, and its serum concentration can be one of the specific biomarkers of stroke and related complications because of its high activity, broad and complex effects. By summarizing relevant literature, this article aims to gain a thorough understanding of the potential clinical applications of NPY in the treatment of stroke, identification of stroke and its related complications, and assessment of prognosis.

Combustion Characterization and Kinetic Analysis of Mixed Sludge and Lignite Combustion.

To investigate the feasibility and reaction mechanism of combusting sewage sludge and brown coal in a mixture. Thermal behavior evaluation of combustion characteristics, interactions, and kinetic analysis of sludge-lignite mixture combustion by thermogravimetry (TG). The results showed that the combustion performance of the mixed samples was all in between that of the lignite and sludge samples. The combined combustion index gradually decreased with the increase in sludge mixing. The addition of sludge favors the ignition of the mixture but is not conducive to overall stable combustion. The synergies between the sludges, as assessed by the mass loss curves, are reflected in the ash removal and coke oxidation stages. When the mixture of sludge and lignite is burned at a ratio of 10 wt %, the calorific value can still reach 20.3 MJ/kg, which is only about 4.2% lower than that of burning lignite alone. Application of the kinetic models of FWO, Starink, KAS, and Friedman, in turn, determined a minimum average activation energy of only 132.50 kJ/mol. In addition, the reaction was judged to be a simple complexation reaction by analyzing the thermodynamic parameters (ΔG, ΔS, ΔH, and A), with the combustion process approaching thermodynamic equilibrium and forming stable products. The nucleation model A4.2 can be used as the best reaction mechanism model for sludge-lignite mixed combustion.

Whether serum leptin and insulin-like growth factor-1 are predictive biomarkers for post-stroke depression: A meta-analysis and systematic review.

Leptin and insulin-like growth factor-1 (IGF-1) may play a role in clinical identification of post-stroke depression (PSD). Here, eight databases (including CNKI, Wanfang, SinoMed, VIP, PubMed, the Cochrane Library, Embase, and the Web of Science) were employed to search for studies on serum leptin and insulin-like growth factor-1 expression levels in patients with PSD. In total, 13 articles were included, of which 6 studies investigated the expression level of serum leptin in patients with PSD, 7 studies explored the serum IGF-1 in PSD patients. Then, the RevMan 5.4 software was used for meta-analysis. The results showed that serum leptin levels were significantly higher in PSD patients than in patients without PSD (SMD = 1.54, 95% CI: 0.84, 2.23; P = 0.006). The result of subgroup analysis showed that the serum leptin levels in PSD patients were significantly higher than those without PSD in acute phase (SMD = 1.38, 95% CI: 0.04, 2.71; P = 0.04), subacute phase (SMD = 2.31, 95% CI: 0.88, 3.73; P = 0.001), and chronic phase (SMD = 1.02, 95% CI: 0.43, 1.60; P = 0.0007); There was no significant difference in serum IGF-1 level between PSD patients and patients without PSD (SMD = 0.49, 95% CI: -0.55, 1.52; P = 0.36). Moreover, the subgroup analysis also showed that there was no statistical difference in acute stage (SMD = 0.36, 95% CI: 0.89, 1.60; P = 0.57). Our study provides evidence to prove that serum leptin level has potential clinical application value as biomarkers for identifying PSD.

Assisted-GNSS positioning algorithm based on one-way fuzzy time information.

In order to solve the problem that the accuracy of approximate position and approximate time information is limited by the traditional auxiliary positioning algorithm, this paper analyzes the problem that the calculation amount may increase and fail when these auxiliary information exceeds the precision requirement range and puts forward a positioning algorithm based on one-way fuzzy time assistance that is suitable for the positioning solution of GNSS satellite navigation receivers under the condition of fuzzy time information, such as the rotation condition. Methods using the reference information in the ephemeris information, the relatively accurate approximate time information can be reasonably searched and verified so as to achieve the effect of obtaining the positioning result with less calculation. The experimental results show that this method can accurately calculate the exact position even if there is an error in the approximate position information under the condition of one-way time assistance, which not only solves the problem that it cannot be positioned under the conditions of rotation but also does not increase the additional calculation amount and has practical engineering value.

Preparation of Activated Boron Nitride and Its Adsorption Characteristics for Zn, Cu, and Cd in Flue Gas.

Developing non-carbon-based adsorbents is essential for removing heavy metals from post-incineration flue gas. In this study, a new high-temperature-resistant adsorbent-activated boron nitride (BN) was prepared using precursors combined with a high-temperature activation method. The adsorption characteristics of BN for Zn, Cu, and Cd in simulated flue gas and sludge incineration flue gas were investigated using gas-phase heavy metal adsorption experiments. The results showed that BN prepared at 1350 °C for 4 h had defect structures, abundant pores, functional groups, and a high specific surface area of 658 m2/g. The adsorption capacity of BN in simulated flue gases decreases with increasing adsorption temperature, whereas it is always higher than that of activated carbon (AC). The total adsorption capacities for Zn, Cu, and Cd were the highest at 50 °C with 48.3 mg/g. BN had strong adsorption selectivity for Zn, with a maximum adsorption capacity of 54.45 mg/g, and its adsorption process occurred mainly on the surface. Cu and Cd inhibited Zn adsorption, leading to a decrease in the Zn adsorption capacity. In sludge incineration flue gas, BN can quickly reach adsorption equilibrium. The BN had a synergistic disposal capacity for heavy metals and fine particulate matter. The maximum adsorption capacity was reduced compared to the simulated flue gas adsorption capacity, which was 5.1 mg/g. However, BN still exhibited a strong adsorption selectivity for Zn, and its adsorption capacity was always greater than that of AC. The rich functional groups and high specific surface area enable BN to physically and chemically double-adsorb heavy metals.

Modular and Selective Access to Functionalized Alkynes and Allenes via the Intermediacy of Propargylic Acetates.

We report an efficient one-pot, two-step procedure for the modular synthesis of α-difunctionalized alkynes and trisubstituted allenes by sequential cross-coupling of benzal gem-diacetates with organozinc or -copper reagents in the absence of external transition metals. The intermediacy of propargylic acetates enables the divergent and selective synthesis of these valuable products. This method features its readily accessible substrates, relatively mild conditions, wide scope, and scalability in practical synthesis.

Changes in Sources and Composition of Beach Waste in Coastal Cities around the Bohai Sea of China during the Tourist Peak and Off-Peak Seasons.

Beach waste is an important pollutant in the Bohai Sea and coastal cities around the Bohai Sea and has raised many social and environmental concerns in China. The semi-closed characteristics of the Bohai Sea, the well-developed tourism, the special industrial structure and residents' living habits endow the beach waste around Bohai sea with a unique character that should be explored. This study investigated changes in the sources and composition of beach waste in coastal cities around the Bohai Sea of China during the tourist peak and off-peak seasons. Beach waste from twenty beaches in thirteen coastal cities around the Bohai Sea was sampled and analyzed in March and August 2021, respectively. The results showed that beach waste around the Bohai Sea was characterized by large quantities and small weights and was greatly affected by human coastal activities. The sources and composition of beach waste from different coasts and different seasons varied, whereas the overall trend was consistent. In terms of composition, beach waste in both the tourist peak season and off-peak season was mainly composed of plastics, fabrics and paper, which accounted for more than 70% of the total in weight. Meanwhile, the proportion of plastics in the total quantity of beach waste was greatest (maximum of up to 71%) and exhibited seasonal fluctuations, trending higher in the tourist peak season than in the off-peak season. In contrast, trends in the proportion of paper and fabrics in the total quantity and total weight of beach waste were relatively stable in different seasons. In terms of sources, beach waste mainly derived from human coastal activities, the proportion of which in the total quantity of beach waste in the tourist peak season reached 70.55% and was 11% higher than that in the tourist off-peak season. Shipping/fishing activities were the second largest source of beach waste, and their proportion in the total quantity of beach waste in the tourist peak season was 5% lower than that in the tourist off-peak season, as the tourist peak season around the Bohai Sea coincides exactly with the fishing moratorium. The quantity of smoking-related waste only accounted for 9.35% and 7.73% of beach waste in the tourist peak and off-peak seasons, respectively. The special semi-enclosed structure of the Bohai gulf, surrounded by land on three sides, aggravated the accumulation of beach waste on the coast. Source reduction and classified recovery, collaborative management of marine waste and beach waste, and joint prevention and control mechanisms of three provinces (Liaoning, Hebei and Shandong) and one municipality (Tianjin) were suggested for comprehensive management of beach waste in coastal cities around the Bohai Sea of China. This study provided valuable information for beach waste management in coastal cities around the Bohai Sea of China.

Hydrothermal liquefaction of sewage sludge into biocrude: Effect of aqueous phase recycling on energy recovery and pollution mitigation.

Hydrothermal liquefaction (HTL) of sewage sludge is facing the challenges of low biocrude yield, a large number of intractable aqueous phase and heavy metals pollution. In this study, the aqueous phase produced by HTL was recycled as solvent with an aim to improve the biocrude yield and mitigate potential pollution. Results showed that the recycling of aqueous phase increased the biocrude yield from 17.9 to 30.5% and the energy recovery ratio from 40.3 to 61.7%. The recycling could increase the contents of Zn, Cu, Pb and Cr in solid residues by 2.7-3.0 times. It is worth emphasizing that the recycling reduced the COD of aqueous phase by 24.9%. However, the enhanced protein hydrolysis process reduced the calorific value of biocrude from 36.4 to 28.5 MJ/kg, and promoted the migration of the nitrogen to the aqueous phase, which was not environmentally favourable for the direct usage in diesel engines. Analysis showed that the ketones and the phenols in aqueous phase participated in HTL process as reactants, and the acids promoted the hydrolysis of protein in the sludge. Overall, the recycling of aqueous phase effectively improved the energy recovery and alleviated pollution of the sludge HTL.

The Motion Behavior of Micron Fly-Ash Particles Impacting on the Liquid Surface.

The motion behavior of particles impacting on the liquid surface can affect the capture efficiency of particles. It was found that there are three kinds of motion behaviors after particle impact on the liquid surface: sinking, rebound, and oscillation. In this paper, the processes of micron fly-ash particles impacting on the liquid surface were experimentally studied under normal temperature and pressure. The impact of fly-ash particles on the liquid surface was simulated by a dynamic model. Based on force analysis, the dynamic model was developed and verified by experimental data to distinguish between three motion behaviors. Then, the sinking/rebound critical velocity and rebound/oscillation critical velocity were calculated by the dynamic model. The critical velocities of particles impacting on the liquid surface under different particle sizes, receding angles, and surface tension coefficients were analyzed. As the particle size increased, sinking/rebound critical velocity and rebound/oscillation critical velocity decreased. As the receding angle increased, sinking/rebound critical velocity remained unchanged, and the rebound/oscillation critical velocity decreased. As the liquid surface tension coefficient increased, sinking/rebound critical velocity and rebound/oscillation critical velocity increased. On this basis, the behaviors of particles impacting on the liquid at low velocity were analyzed.

Study on the Properties and Heavy Metal Solidification Characteristics of Sintered Ceramsites Composed of Magnesite Tailings, Sewage Sludge, and Coal Gangue.

With the rapid development of industry, the disposal of industrial solid waste needs to be solved urgently in China. Thus, an effective disposal method should be proposed to recycle these solid wastes in an environmentally friendly and sustainable manner. In this paper, ceramsite was prepared from sewage sludge (SS), magnesite tailings (MTs), and coal gangue (CG). The influence of the material ratio and sintering temperature on the properties of the ceramsite was investigated. The results show that the ceramsite had better properties when the following parameters were used: a ratio of SS: CG: MT of 4.5:4:1.5; a sintering temperature of 1250 °C; a compressive strength of 11.2 MPa (or it can be rounded to 11; our major remark relates to significant figures, and they should be up to 2-3 figures, according to measurement errors); a water absorption of 3.54%; and apparent and bulk densities of 1.19 and 0.81 g/cm3, respectively. The strength was superior to more than twice the 900-density grade prescribed by the Chinese national standard. After sintering, most of the heavy metals in the ceramsite mainly existed in the form of residue state (FD), meaning that they were highly stable. The leaching concentrations of Zn and Ni from the ceramsite were 0.72 and 0.25 mg/L lower than the prescribed regulatory limits (2.0 and 0.1 mg/L). The overall pollution toxicity index (OPTI) was only 240, less than that of raw pellets, indicating that the environmental risk is low. Not only did the ceramsite, prepared from SS, CG, and MT, exhibit excellent chemical properties, but it also proved to be an environmentally safe material. Therefore, it is an effective approach to realize the collaborative treatment of SS, CG, and MT by preparing ceramsite.

A Novel NDT Scanning System Based on Line Array Fast Neutron Detector and D-T Neutron Source.

A novel non-destructive testing scanning system based on a large-size line array fast neutron detector and compact D-T neutron source has been constructed. The scanning range is up to 1000 mm, and the resolution is better than 1 mm. The fast neutron detection subsystem consists of a polypropylene zinc sulfide scintillator embedded with wavelength-shifting fibers, coupled with a light lens and a scientific CCD camera. With a new rotating tritium target, the lifetime of the compact D-T neutron source could achieve ten hours. The experimental results indicate that the scanning method based on line array fast neutron detector and D-T neutron source is feasible and enables the detection of slits on the order of 0.5 mm in width. Fast neutron tomography has been realized by this detection system too.

Links between carbon/nitrogen ratio, synergy and microbial characteristics of long-term semi-continuous anaerobic co-digestion of food waste, cattle manure and corn straw.

Links between carbon/nitrogen (C/N) ratio, synergy and microbial characteristics of anaerobic co-digestion of food waste (FW), cattle manure (CS) and corn straw (CS) were investigated. Digesters with 100% CS, 25% FW + 75% CS, 25% CM + 75% CS suffered acid inhibition, in close association with unbalanced C/N and the resulting recessions of Syntrophomonadaceae and Methanosaeta. Co-digestion overcame C/N imbalance and achieved multiple synergies. Process performance had a positive correlation with Syntrophomonadaceae. Digester with 75% FW + 25% CS had most Syntrophomonadaceae (26.7%) and methane yield (467.3-507.6 mL/g VS) among co-digestion trials. Synergy was greater under higher load and exhibited a good correlation with C/N ratio. Co-digestion of FW, CM and CS (2:2:1) with suitable C/N ratio (20.79) obtained the greatest synergistic rate (14.6%). Unstable systems were improved by adjusting C/N ratio to 30 via urea, which stimulated Methanosarcina growth therefore enhanced methanogenic pathway diversity and ensured powerful methanogenic functions.

Ferrate(VI) Oxidation Mechanism of Substituted Anilines: A Density Functional Theory Investigation.

Ferrate(VI) (Fe(VI)) is a promising oxidant coagulant and disinfectant for the degradation of organic micropollutants. However, it is hard to elucidate the detailed oxidation mechanism through the current experimental approaches. Substituted anilines (SANs) are important chemical compounds that are widely used in many industries. This paper presents the use of density functional theory (DFT) to understand the oxidation mechanism of SANs by Fe(VI) and the effect of substituents. The calculation results revealed that the primary oxidations of SANs follow the hydrogen atom transfer (HAT) mechanism. Interestingly, the hydroxyl oxygen of HFeO4 - is more reactive than the carbonyl oxygen when reacting with SANs. The formation of the SAN radical is crucial, and all of the products are formed from it. Azobenzene is more favorable to generate the above products. In addition, the obtained results indicate that this kind of substituent has a much greater influence on the reaction rather than the position. Thus, the present study provides a valuable insight into the transformation pathways of SANs in the Fe(VI) oxidation process and the effects of the substituent on oxidation. These results will advance the understanding of Fe(VI) involved in wastewater treatment.

Links between synergistic effects and microbial community characteristics of anaerobic co-digestion of food waste, cattle manure and corn straw.

Links between synergy and microbial community characteristics in co-digestion of food waste (FW), cattle manure (CM) and corn straw (CS) were investigated. Mono-digestion of FW and CS were inhibited by organic acids. Co-digestion of FW with CM achieved greater synergistic rates (18.5% and 22.3%) than CM with CS (14.8% and 12.3%). Synergy resulted from coupling effects of improving nutrient balance, dilution of toxic compounds, higher buffering capacity, detoxification based on co-metabolism, which ultimately reflected in microbial community functions. Although co-digestion of FW with CS exhibited lowest synergistic rates (7.9% and 4.9%), detoxification based on co-metabolism of syntrophic communities of Syntrophomonadaceae with hydrogenotrophic methanogens accelerated system recovery. Digester with the greatest synergy (65% FW + 35% CM) maintained dominant growth of hydrogenotrophic methanogens (68.9%), highest methanogenic community diversity and relative abundance of Methanosarcina (14.6%), which sustained more diverse and switchable methanogenic pathways therefore ensured powerful methanogenic functions and vigorous methanogenic capability.

Responses of anaerobic digestion of food waste to coupling effects of inoculum origins, organic loads and pH control under high load: Process performance and microbial characteristics.

This study investigated responses of anaerobic digestion (AD) of food waste (FW) with different inocula to varying organic loads and to pH control under high load in terms of process performance and microbial characteristics. Without pH control, digester inoculated by thickened sludge obtained high methane yield of 547.8 ± 27.8 mL/g VS under organic load of 7.5 g VS/L but was inhibited by volatile fatty acids (VFAs) under higher loads (15 and 30 g VS/L). However, digesters inoculated by anaerobic sludge obtained high methane yields of 575.9 ± 34.2, 569.3 ± 24.8 and 531.9 ± 26.2 mL/g VS under organic loads of 7.5, 15 and 30 g VS/L and VFAs inhibition only appeared under extremely high load of 45 g VS/L. Digesters under VFA inhibition with high load were significantly enhanced by controlling single ecological factor pH at 6.5, 7.0 and 7.5, as indicated by shorter lag phases, higher peak values of methane production rate, greater methane yields and fast VFAs degradation. Maximum methane recovery was obtained with pH control at 7.5 under high load. VFA inhibition was accompanied by the degeneration of ecological functions of Syntrophomonadaceae and unidentified Bacteroidales and the dominant growth of unidentified Clostridiales. Under high load and pH control, high stability was strongly associated with obvious growth of Methanosarcina, which enriched methanogenic pathways thus improved system robustness and tolerance to VFAs. Moreover, pH control stimulated the growth of syntrophic Bacteria Syntrophomonadaceae while maintaining the high activity of hydrogenotrophic methanogens therefore sustained efficient syntrophic communities of Bacteria and methanogens and avoided over accumulation of VFAs. pH control promoted adaptive selection of methanogens, leading to obvious decline of archaeal community diversity. This study provided practical guidance on digester configurations of high-load AD of FW and expanded the understanding of responses to coupling effects of inoculum origins, organic loads and pH control under high load concerning process performance and microbial community dynamics.

[Net ecosystem carbon exchange and its affecting factors in a deciduous broad-leaved forest in Songshan, Beijing, China]. / åŒ—äº¬æ¾å±±å¤©ç„¶è½å¶é˜”å¶æž—ç”Ÿæ€ç³»ç»Ÿå‡€ç¢³äº¤æ¢ç‰¹å¾åŠå ¶å½±å“å› å­.

Forests play an important role in terrestrial carbon cycles. The mechanism underlying carbon balance in temperate deciduous broad-leaved forests is not clear. In this study, net ecosystem exchange (NEE) and environmental factors, including air temperature (Ta), soil temperature (Ts), photosynthetically active radiation (PAR), vapor pressure deficit (VPD), soil water content (SWC) and precipitation (P) were continually measured using eddy covariance techniques in 2019 in a deciduous broad-leaved forest in Songshan, Beijing. We analyzed the characteristics of NEE and its response to environmental factors. The results showed that, at diurnal scale, the monthly averaged NEE exhibited a "U" shape curve (i.e., being a carbon sink over daytime while being a carbon source during nighttime) over the growing season. During the non-growing season, NEE was positive (i.e., carbon source) at diurnal scale. At the seasonal scale, NEE exhibited a unimodal curve. The annual cumulative NEE was -111 g C·m-2·a-1. Annual ecosystem respiration was 555 g C·m-2·a-1, while gross ecosystem productivity was 666 g C·m-2·a-1. Carbon sequestration peaked in June, while emission peaked in November. PAR was the dominant factor affecting daytime NEE (NEEd). VPD was the main factor that indirectly affected daytime NEEd, with an optimal VPD value that maximizes daytime NEE around 1-1.5 kPa. Soil temperature was the main factor affecting nighttime NEE (NEEn). SWC was a limiting factor for NEEn. Too high or too low SWC would inhibit NEEn, with an optimal SWC value of 0.28 m3·m-3.

Comprehensive Evaluation of the Control Efficiency of Heavy-Metal Emissions during Two-Step Thermal Treatment of Sewage Sludge.

Recycling the phosphorus in sludge by incineration has received great interest at home and abroad. However, heavy metals (HMs) is a restrictive factor for SS thermal treatment. In this study, a comprehensive evaluation method was adopted to evaluate the comprehensive control efficiency of HM emissions during two-step thermal treatment (incineration-calcination). The effects of temperature, calcination time, and additives (CaO and NaCl) on leaching rates, stabilized rates, and comprehensive control efficiency of HM emissions were investigated. Results showed that comprehensive control efficiency increased significantly with an increase of temperature because of the transformation of chemical speciation from a leachable to a more stable combined form. Additives Cao and NaCl promoted the volatilization of HMs and reduced the comprehensive control efficiency. The highest comprehensive control efficiency of HM emissions was 78% when the incineration temperature reached 950 °C. Furthermore, a comparison was made between leaching rates, stabilized rates, and a comprehensive evaluation method. The results were inconsistent when leaching rates and stabilized rates were adopted. In contrast, when the comprehensive evaluation method was used, the results were coordinated and unique. This work can provide a promising approach for the evaluation of control efficiency of HM emissions during the process of thermal treatment of sludge.