Research progress in the degradation of printing and dyeing wastewater using chitosan based composite photocatalytic materials.

The surge in economic growth has spurred the expansion of the textile industry, resulting in a continuous rise in the discharge of printing and dyeing wastewater. In contrast, the photocatalytic method harnesses light energy to degrade pollutants, boasting low energy consumption and high efficiency. Nevertheless, traditional photocatalysts suffer from limited light responsiveness, inadequate adsorption capabilities, susceptibility to agglomeration, and hydrophilicity, thereby curtailing their practical utility. Consequently, integrating appropriate carriers with traditional photocatalysts becomes imperative. The combination of chitosan and semiconductor materials stands out by reducing band gap energy, augmenting reactive sites, mitigating carrier recombination, bolstering structural stability, and notably advancing the photocatalytic degradation of printing and dyeing wastewater. This study embarks on an exploration by initially elucidating the technical principles, merits, and demerits of prevailing printing and dyeing wastewater treatment methodologies, with a focal emphasis on the photocatalytic approach. It delineates the constraints encountered by traditional photocatalysts in practical scenarios. Subsequently, it comprehensively encapsulates the research advancements and elucidates the reaction mechanisms underlying chitosan based composite materials employed in treating printing and dyeing wastewater. Finally, this work casts a forward-looking perspective on the future research trajectory of chitosan based photocatalysts, particularly in the realm of industrial applications.

Cullin7 induces docetaxel resistance by regulating the protein level of the antiapoptotic protein Survivin in lung adenocarcinoma cells.

Background: Lung adenocarcinoma (LUAD) is the most common subtype of non-small cell lung cancer (NSCLC). Chemotherapy resistance is the main cause of chemotherapy failure. Cullin7 (Cul7) is highly expressed in LUAD and is associated with poor prognosis. Moreover, Cul7 is abnormally overexpressed in docetaxel-resistant LUAD cells. Therefore, further exploration of the role and molecular mechanism of Cul7 in LUAD docetaxel resistance is necessary. Methods: We established docetaxel-resistant cell lines (A549DTX and H358DTX cell lines) by exposing cells to gradually increasing concentrations of docetaxel. Cell (A549, A549DTX, H358, and H358DTX cell lines) sensitivity to docetaxel was determined via a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymmethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. And then quantitative polymerase chain reaction (qPCR) and Western blotting were performed to measure the expression of Cul7 and Survivin in A549, A549DTX, H358, and H358DTX cell lines. Subsequently, we knocked down Cul7 in docetaxel-resistant cells and overexpressed Cul7 in parental cells via lentiviral transduction to further validate the correlation between Cul7 and docetaxel resistance, while exploring the molecular mechanism of docetaxel resistance it caused. Immunofluorescence and immunohistochemical (IHC) staining were also used to evaluate the expression and cellular localization of Cul7. To confirm the effect of Cul7 expression on cell apoptosis, we used flow cytometry to detect the apoptosis rate of A549 and A549DTX cells with the same drug concentration. Results: Cul7 was highly expressed in A549DTX and H358DTX cells. However, when Cul7 expression was knocked down in A549DTX and H358DTX cells, cell sensitivity to docetaxel was significantly increased. In addition, we found that Cul7 was coexpressed with Survivin. Silencing Survivin reversed the docetaxel insensitivity caused by Cul7 overexpression. High expression of Cul7 and Survivin in docetaxel-resistant LUAD cells inhibited the intrinsic apoptosis pathway and promoted cell proliferation. Therefore, the Cul7/Survivin axis may play a role in inducing LUAD docetaxel chemoresistance. Conclusions: Cul7 and Survivin were both highly expressed in docetaxel-resistant LUAD cells. Our results suggest that Cul7 may inhibit apoptosis and promote the proliferation of LUAD cells by increasing the Survivin protein level, which in turn contributes to docetaxel chemoresistance in LUAD.

Selective adsorption of tetracycline and copper(II) on ion-imprinted porous alginate microspheres: performance and potential mechanisms.

A novel epichlorohydrin and thiourea grafted porous alginate adsorbent (UA-Ca/IIP) was synthesized using ion-imprinting and direct templating to remove copper ions (Cu(II)) and tetracycline (TC) in aqueous solution. UA-Ca/IIP demonstrated great selectivity for Cu(II) and TC among different coexisting anions (CO32-, PO43- and SO42-), cations (Ca2+, Mg2+ and NH4+), and antibiotics (oxytetracycline and sulfamethoxazole). The adsorption of TC and Cu(II) by UA-Ca/IIP was significantly affected by the pH of the solution, and the quantity of TC and Cu(II) adsorbed reached a maximum at pH 5. A pseudo-second-order model better fitted the kinetic data; the Langmuir model predicted the maximum adsorption quantities 3.527 mmol TC g-1 and 4.478 mmol Cu(II) g-1 at 298 K. Thermodynamic studies indicated that the TC and Cu(II) adsorption was more rapid at a higher temperature. Antagonistic and synergistic adsorption experiments showed that the adsorption capacity of TC would increase significantly with the increase of Cu(II) concentration. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that along with the influence of pH, electrostatic interaction and complexation were the main mechanisms of TC and Cu(II) adsorption. Regeneration experiments revealed that TC and Cu(II) were removed efficiently and that UA-Ca/IIP was recyclable over the long term. These results show that the modified porous alginate microsphere is a green and recyclable adsorbent, which has good selectivity and high adsorption performance for the removal of TC and Cu(II).

Comprehensive removal of various dyes by thiourea modified chitosan/nano ZnS composite via enhanced photocatalysis: Performance and mechanism.

Dyeing wastewater is a carcinogenic pollutant, which is widely known for its harmful effects on humans and marine organisms. In this study, a novel composite was prepared by blending thiourea modified chitosan with zinc sulfide nanoparticles (T-CS/ZnS) to comprehensively remove methyl orange (MO), rhodamine B (Rh B), and methylene blue (MB) effectively. Characterization results suggested that the synthesized composite has an irregular and rough surface that provided high specific surface area for adsorption process, while the strong optical response and low bandgap width contributed to the subsequent photocatalytic degradation of adsorbed dye molecules. Under optimum experimental conditions, the removal rates of MO, Rh B, and MB were 99.59 %, 99.49 %, and 91.04 %, respectively. Amino and hydroxyl groups provide electrons in photocatalytic reactions. The reaction process is consistent with the quasi-first-order kinetic model, and the material has good stability and regeneration potential. This study indicated that T-CS/ZnS composite is a highly effective material for the treatment of dyeing wastewaters.

Synthesis of triethylenetetramine modified sodium alginate/CuS nanocrystal composite for enhanced Cr(VI) removal: Performance and mechanism.

Photocatalysis has been widely used for the removal of hexavalent chromium from wastewater as an efficient and environmental friendly method. However, conventional photocatalysts generally exhibit poor adsorption properties toward Cr(VI), resulting in unsatisfactory performance in high concentrated wastewaters. In this study, we synthesized a novel composite material with high Cr(VI) adsorption ability by blending prepared CuS nanocrystals into triethylenetetramine modified sodium alginate for the enhanced photocatalytic removal of Cr(VI). Effect of CuS dosage, pH value, light source and intensity were discussed for the optimum Cr(VI) removal conditions. The synthesized composite has shown good adsorption performance toward Cr(VI) and the overall removal rate reached 98.99 % within 50 min under UV light irradiation with citric acid as hole scavenger. Adsorption isotherm, thermodynamics, and kinetics with corresponding model fitting were discussed, which suggested that the monolayer and chemical adsorption dominated the adsorption process. Characterization results indicated that amino and hydroxyl groups contributed electrons in the photocatalysis reaction for the reduction of Cr(VI) to Cr(III). CuS nanocrystals can enhance the surface charge and light absorbance ability of the composite, and the Cr(VI) removal was governed by electrostatic interaction and photo-induced redox reaction.

Application of zeolite synthesized from coal fly ash via wet milling as a sustainable resource on lead(II) removal.

In this work, zeolite based on coal fly ash was firstly synthesized via wet milling for the adsorption of lead (Pb(II)). The effects of contact time, solid-to-liquid ratio and initial pH of solution on Pb(II) removal were investigated in detail. The experimental data showed that synthesized zeolite has high adsorption capacity of 99.082 mg of Pb(II) per gram of adsorbent. Coal fly ash zeolite synthesized by wet milling has good Pb(II) adsorption performance when the initial pH of the solution is above 5. The adsorption kinetic results demonstrated that removal of Pb(II) via the synthesized zeolite followed pseudo-second-order kinetic model. X-ray photoelectron spectroscopy results directly demonstrated the adsorption between Pb(II) and synthesized zeolite, and a possible reaction pathway was proposed. Specifically, the removing mechanism of Pb(II) from aqueous solution via the synthesized zeolite involves two stages: one is that Pb(II) in aqueous solution is absorbed on the interior of the synthesized zeolite, and the other is chemical precipitation.

A case report of small cell ovarian neuroendocrine carcinoma combined with immunochemotherapy.

BACKGROUND: Small cell ovarian neuroendocrine (NE) carcinoma is a rare NE tumor with a low incidence, poor prognosis, and no standardized treatment. To date, there have been no clear reports on the efficacy or prognosis of combined immunological and chemotherapy-based approaches in patients with this type of tumor. METHODS: We administered the immune checkpoint inhibitor tirelizumab (PD-1 mab), in combination with etoposide and cisplatin chemotherapy (EP), to a patient with small cell ovarian NE carcinoma to examine its efficacy and safety. RESULTS: The evaluation of efficacy was PR for every 2 courses of application, and immunomaintenance therapy was administered after 6 courses of treatment. CONCLUSION: Our studies indicate that tirelizumab combined with EP, may be an effective treatment for small cell ovarian NE carcinoma.

Label-Free Small Extracellular Vesicles Capturing Strategy for Lung Cancer Diagnosis and Typing Based on a Natural Polyphenol-Metal Three-Dimensional Network.

Small extracellular vesicles (sEVs) have been increasingly recognized as circulating biomarkers and prognosticators for disease diagnosis. However, the clinical applications of sEVs are seriously limited by the lack of a robust and easy scale-up isolation technique. Herein, the feasibility of a polyphenol-metal three-dimensional (3D) network for label-free sEV isolation was explored. As a proof-of-concept, with tannic acid (TA) as the polyphenolic ligand and Fe(III) as the coordinated metal, the TA-Fe(III) 3D network coating mesoporous silica beads (SiO2@BSA@Fe-TA6) was designed and fabricated via a coordination-driven layer-by-layer self-assembly approach. The successful fabrication of SiO2@BSA@Fe-TA6 was validated by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. With the low-cost TA (as low as US$ 0.18/g) as the probe, SiO2@BSA@Fe-TA6 achieved universal capture toward sEVs in different cells and plasma samples. The capture efficiency reached 85.4 ± 1.5%, which is comparable to the antibody-based capture techniques and significantly higher than the ultracentrifugation (UC) method. The purity of sEVs isolated by SiO2@BSA@Fe-TA6 from the H1299 cell culture supernatant was measured as (1.07 ± 0.14) × 1011 particles/µg, which is 3.1 times higher than that via the UC method. Another important superiority of SiO2@BSA@Fe-TA6 is the facile self-assembly approach, which can harvest a yield of up to grams, allowing simultaneous processing of more than 500 plasma samples. The SiO2@BSA@Fe-TA6-based strategy was further successfully employed to distinguish nonsmall cell lung cancer (NSCLC) and small cell lung cancer (SCLC) with an accuracy of 87.1%. The developed SiO2@BSA@Fe-TA6 is a label-free, universal, low cost, and easy scale-up technique for sEV-based liquid biopsy in lung cancer diagnosis and typing.

Elevated AKIP1 expression is associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma.

A-kinase-interacting protein 1 (AKIP1), as a recently discovered oncoprotein, promotes cell malignant behaviors in gynecological malignancies. To the best of our knowledge, no study reports its clinical value in patients with endometrial carcinoma. The present study aimed to explore the association between AKIP1 expression and clinical features and survival in patients with endometrial carcinoma, and to assess the effect of AKIP1 knockdown on the regulation of chemosensitivity in vitro. The tumor and adjacent tissue specimens from 101 patients with endometrial carcinoma were retrieved for AKIP1 protein expression analysis using an immunohistochemistry (IHC) assay. Meanwhile, specimens from 54 patients with endometrial carcinoma were analyzed for AKIP1 mRNA expression using reverse transcription-quantitative PCR. Furthermore, an in vitro experiment was conducted in the Ishikawa cell line to determine the effect of AKIP1 modification on the chemosensitivity of cisplatin and paclitaxel. AKIP1 IHC score (P<0.001) and mRNA expression levels (P<0.001) were increased in tumor tissues compared with those in adjacent tissues. Moreover, increased AKIP1 IHC score was associated with lymphovascular invasion (P=0.007), advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.002) and shorter overall survival (OS) time (P=0.035) in the patients with endometrial carcinoma. Meanwhile, upregulated AKIP1 mRNA expression levels were associated with lymphovascular invasion (P=0.020) and advanced FIGO stage (P=0.027) in the patients with endometrial carcinoma. Multivariate Cox regression showed that tumor AKIP1 protein expression (high vs. low) independently predicted a shorter OS time (P=0.036). Silencing of AKIP1 decreased Ishikawa cell viability when treated with 5, 10, 20 and 40 µM cisplatin (all P<0.05) and decreased the half maximal inhibitory concentration value of cisplatin (P=0.003), whereas its effect on paclitaxel chemosensitivity was less obvious. Overall, elevated AKIP1 expression was associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma.

Repurposing N-Doped Grape Marc for the Fabrication of Supercapacitors with Theoretical and Machine Learning Models.

Porous carbon derived from grape marc (GM) was synthesized via carbonization and chemical activation processes. Extrinsic nitrogen (N)-dopant in GM, activated by KOH, could render its potential use in supercapacitors effective. The effects of chemical activators such as potassium hydroxide (KOH) and zinc chloride (ZnCl2) were studied to compare their activating power toward the development of pore-forming mechanisms in a carbon electrode, making them beneficial for energy storage. GM carbon impregnated with KOH for activation (KAC), along with urea as the N-dopant (KACurea), exhibited better morphology, hierarchical pore structure, and larger surface area (1356 m2 g-1) than the GM carbon activated by ZnCl2 (ZnAC). Moreover, density functional theory (DFT) investigations showed that the presence of N-dopant on a graphite surface enhances the chemisorption of O adsorbates due to the enhanced charge-transfer mechanism. KACurea was tested in three aqueous electrolytes with different ions (LiOH, NaOH, and NaClO4), which delivered higher specific capacitance, with the NaOH electrolyte exhibiting 139 F g-1 at a 2 mA current rate. The NaOH with the alkaline cation Na+ offered the best capacitance among the electrolytes studied. A multilayer perceptron (MLP) model was employed to describe the effects of synthesis conditions and physicochemical and electrochemical parameters to predict the capacitance and power outputs. The proposed MLP showed higher accuracy, with an R2 of 0.98 for capacitance prediction.

Photocatalytic Removal of Cr(VI) by Thiourea Modified Sodium Alginate/Biochar Composite Gel.

Heavy metal pollution is an important problem in current water treatments. Traditional methods for treating chromium-containing wastewater have limitations such as having complicated processes and causing secondary pollution. Therefore, seeking efficient and fast processing methods is an important research topic at present. Photocatalysis is an efficient method to remove Cr(VI) from aqueous solutions; however, conventional photocatalysts suffer from a low metal absorption capacity, high investment cost, and slow desorption of trivalent chromium from the catalyst surface. In this study, a novel composite gel was synthesized by chemically modifying thiourea onto sodium alginate, which was then mixed with biochar. The composite gel (T-BSA) can effectively remove 99.98% of Cr(VI) in aqueous solution through synergistic adsorption and photocatalytic reduction under UV light irradiation. The removal mechanism of Cr(VI) was analyzed by FT-IR, FESEM, UV-DRS and XPS. The results show that under acidic conditions, the amino group introduced by chemical modification can be protonated to adsorb Cr(VI) through electrostatic interaction. In addition, the biochar as a functional material has a large specific surface area and pore structure, which can provide active sites for the adsorption of Cr(VI), while the photo-reduced Cr(III) is released into the solution through electrostatic repulsion, regenerating the adsorption sites, thereby improving the removal performance of Cr(VI). Biochar significantly intensifies the Cr(VI) removal performance by providing a porous structure and transferring electrons during photoreduction. This study demonstrates that polysaccharide-derived materials can serve as efficient photocatalysts for wastewater treatment.

Identification of a novel prognosis-associated ceRNA network in lung adenocarcinoma via bioinformatics analysis.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most common subtype of nonsmall-cell lung cancer (NSCLC) and has a high incidence rate and mortality. The survival of LUAD patients has increased with the development of targeted therapeutics, but the prognosis of these patients is still poor. Long noncoding RNAs (lncRNAs) play an important role in the occurrence and development of LUAD. The purpose of this study was to identify novel abnormally regulated lncRNA-microRNA (miRNA)-messenger RNA (mRNA) competing endogenous RNA (ceRNA) networks that may suggest new therapeutic targets for LUAD or relate to LUAD prognosis. METHODS: We used the SBC human ceRNA array V1.0 to screen for differentially expressed (DE) lncRNAs and mRNAs in four paired LUAD samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to annotate the DE lncRNAs and mRNAs. R bioinformatics packages, The Cancer Genome Atlas (TCGA) LUAD database, and Kaplan-Meier (KM) survival analysis tools were used to validate the microarray data and construct the lncRNA-miRNA-mRNA ceRNA regulatory network. Then, quantitative real-time PCR (qRT-PCR) was used to validate the DE lncRNAs in 7 LUAD cell lines. RESULTS: A total of 2819 DE lncRNAs and 2396 DE mRNAs (P < 0.05 and fold change ≥ 2 or ≤ 0.5) were identified in four paired LUAD tissue samples. In total, 255 of the DE lncRNAs were also identified in TCGA. The GO and KEGG analysis results suggested that the DE genes were most enriched in angiogenesis and cell proliferation, and were closely related to human cancers. Moreover, the differential expression of ENST00000609697, ENST00000602992, and NR_024321 was consistent with the microarray data, as determined by qRT-PCR validation in 7 LUAD cell lines; however, only ENST00000609697 was associated with the overall survival of LUAD patients (log-rank P = 0.029). Finally, through analysis of ENST00000609697 target genes, we identified the ENST00000609697-hsa-miR-6791-5p-RASL12 ceRNA network, which may play a tumor-suppressive role in LUAD. CONCLUSION: ENST00000609697 was abnormally expressed in LUAD. Furthermore, downregulation of ENST00000609697 and its target gene RASL12 was associated with poor prognosis in LUAD. The ENST00000609697-hsa-miR-6791-5p-RASL12 axis may play a tumor-suppressive role. These results suggest new potential prognostic and therapeutic biomarkers for LUAD.

Mechanistic study of Cr (VI) removal by modified alginate/GO composite via synergistic adsorption and photocatalytic reduction.

A novel composite material was prepared by blending graphene oxide into polyethyleneimine grafted sodium alginate. The synthesized material was investigated as adsorbent and photocatalyst for the removal of hexavalent chromium (Cr (VI)) from aqueous solutions. The composite material has shown remarkable removal efficiency for Cr (VI) in high initial concentration solutions as the removal rate reached 86.16% and 99.92% for adsorption and photoreduction, respectively. We discovered experimentally that the adsorption was dominated via electrostatic interaction while the blending of GO could contribute in stimulating electrons for the photoreduction process. Moreover, the photoreduction can alter the surface charge of chromium species, thus electrostatic repulsion could regenerating the active sites of composite spontaneously. The conduction band energy was calculated as -2.04 eV, which proved that blending GO can narrow the bandgap of the composite material, thus enhance the light response and the photoreduction ability towards Cr (VI).

Adsorption of heavy metal ions by sodium alginate based adsorbent-a review and new perspectives.

With the development of modern industry, heavy metal pollution is one of the most important environmental issues. Due to its simplicity and low-cost, adsorption is considered as a green and environmental friendly method to remove heavy metals from industrial effluents. Sodium alginate is a natural polysaccharide, which consists of abundant hydroxyl and carboxyl groups, has been widely reported as the raw material for the adsorption of heavy metals from aqueous solutions. By surface grafting and cross-linking, adsorbents synthesized from sodium alginate have exhibited large uptake capacities as well as high removal rates for heavy metal ions. However, the poor physical strength and plain thermostability have significantly limited the utilization of sodium alginate based materials in industrial applications. Moreover, reductions of specific metal ions were observed in some studies, of which the reduction mechanism is not clearly clarified. In this work, the development of sodium alginate based adsorbents was summarized, including the physicochemical properties of the polymer, the modification of sodium alginate, sodium alginate based composite materials, and the adsorption behaviors as well as the mechanism. Chelation, electrostatic interaction, ion exchange, reduction and photocatalytic reduction were involved in the adsorption process, which can be determined by chemical characterization with further elucidation by density functional theory calculation. Finally, the limitations of sodium alginate based adsorbents were revealed with suggestions for future research.

Investigation of the specularite/chlorite separation using chitosan as a novel depressant by direct flotation.

Chlorite is one of the representative iron-bearing silicates gangue minerals existed in the specularite ores which the traditional depressants are incapable of action in specularite/chlorite separation flotation. An attempt was conducted for the separation of specularite/chlorite with chitosan as a novel depressant through microflotation tests, Zeta potential measurements, adsorption tests, FT-IR, and XPS analysis. The microflotation results show that chitosan selectively depresses chlorite while specularite still keeps in high floatability. Zeta potential measurements and adsorption tests indicate that chitosan mainly adsorbed on chlorite surface, hindering the subsequent adsorption of dodecan-1-amine and leading the hydrophobicity distinction. The FT-IR spectra of chlorite validate the adsorption of chitosan on chlorite. The results of XPS illustrate that electrons partially transferred from chitosan to the aluminum, iron, magnesium, silicon, and adjacent oxygen atoms of silicon atoms in chlorite during the adsorption process.

Selective adsorption of Pd (II) by ion-imprinted porous alginate beads: Experimental and density functional theory study.

In this study, a novel thiourea grafted porous sodium alginate-based adsorbent was synthesized by combining ion-imprinting and direct templating method. Due to ion-imprinting, the prepared adsorbent has demonstrated outstanding selectivity towards Pd (II) from bi-metallic solution at different pH values. Langmuir and both pseudo-first and pseudo-second kinetic equations were used to describe the adsorption isotherm and kinetics, respectively. FT-IR, XPS, and SEM-EDX analyses suggested that selective adsorption of Pd (II) was dominated by electrostatic interactions at pH 1.0 and chelation on imprinted sorption sites at pH 3.0. Density functional theory (DFT) calculation further explained the effect of ion-imprinting and provided two binding configurations, which is consistent with characterization analyses. The pregnant adsorbent can be regenerated and reused by thiourea solution in dilute hydrochloric acid. Therefore, the synthesized adsorbent would be useful as a selective adsorbent for the enrichment of Pd (II) from effluents.

Flotation separation of specularite from chlorite using propyl gallate as a collector.

Separation of specularite from iron-containing silicate iron ore is challenging due to the similar surface properties of minerals and gangues. In this work, propyl gallate (PG) was applied as a chelating collector to separate specularite from chlorite. The flotation results indicated that collector sodium oleate (NaOL) shows little selectivity for the separation of specularite and chlorite. In contrast, the separation of specularite can be achieved with no depressant required when PG was used as the collector. The optimal separation results were obtained for single mineral flotation with recoveries of 87.11% and 6.98% for specularite and chlorite, respectively, and for mixed mineral flotation with 65.13% TFe grade and 76.28% TFe recovery, when the slurry pH was 8 and PG concentration was 40 mg L-1. FT-IR and XPS analyses indicated that PG could be favorably adsorbed on specularite via phenolic hydroxyl groups, and molecular dynamic simulation results further elucidated the adsorption mechanism. This research suggested that the chelating flotation collector could be effective in the separation of minerals from iron-containing silicate iron ores.

Quantification of Total Organic Carbon in Ashes from Smoldering Combustion of Sewage Sludge via a Thermal Treatment-TGA Method.

Self-sustaining smoldering combustion is a promising technology for treating sewage sludge from wastewater treatment plants because of its low energy inputs. Proper use or disposal of the resulting ashes requires thorough characterization of their properties, including the content of total organic carbon (TOC). Here, we develop a two-step method for quantifying TOC in the raw ashes from sewage sludge smoldering combustion. The first step is to thermally treat the raw ashes at 500 °C in N2 for 1 h, followed by ultimate analysis of both the raw ashes and the thermally treated ashes. This enables the quantification of carbon released during thermal treatment. The second step is nonisothermal thermogravimetric analysis (TGA) of the thermally treated ashes, in which the samples are heated to 900 °C at 10 °C/min in air. The weight losses at 310-500 °C are confirmed to be caused by organic carbon oxidation, allowing us to determine the contents of carbon retained in the thermally treated ashes. The sums of these two portions of carbon represent the contents of TOC in the raw ashes, which are ∼0.85-6.52 wt % (dry basis), depending on their locations and particle sizes. The two-step (thermal treatment-TGA) method is validated via a method that includes acid washing of the thermally treated ashes, ultimate analysis of the acid-washed ashes, and TOC analysis of the leachates. The two-step method is simple and accurate and, importantly, provides thorough information on the thermal behavior of the raw and thermally treated ashes.

Investigation of reducing particulate matter (PM) and heavy metals pollutions by adding a novel additive from metallurgical dust (MD) during coal combustion.

In this study, a novel additive from metallurgical dust(MD)was applied to reduce particulate matter (PM) emissions and heavy metals pollutions during coal combustion. PM samples were collected and divided into 13 stages from 0.03 µm to 10 µm. Results showed that the irregular morphology of fine particles with equal to/less than 2.5 µm (PM2.5), fine particles with equal to/less than 4 µm (PM4) and fine particles with equal to/less than10 µm (PM10) gradually became dense with increasing of MD content. The PM10 concentration with 10% MD dosage was about 3 times higher than that of raw coal. Zn, Ti, Cu and Cr were the most abundant elements in all particulate matters (PMs), meanwhile, heavy metals accumulated into large particles with increasing MD content. The mechanism of reducing PM emissions indicated that MD reacted with nucleation elements (Pb, Cd, etc.) and trapped a large amount of alkali metal (Na/K), which aggregated into large particles. The study highlights the potential of adding MD into coal to prevent the attachment of heavy metals onto ultrafine particles, thereby reducing the heavy metals emissions.