Coal Cinder Research Articles

Removal characteristics of high concentration glyphosate in bioretention cells

ABSTRACT Glyphosate, as one of the most widely used pesticides, has been found in rainwater runoff. A bioretention cell with two types of fillers was constructed to explore removal of glyphosate in runoff an transformation of glyphosate in the filler. The type of filler had a significant impact on adsorption and degradation of glyphosate in the bioretention cell. The glyphosate removal efficiencies of coal cinder modified loess (CLB) and zeolite modified loess (ZLB) were 33.13–99.7% and 55.04–99.7%, respectively. Conversion of glyphosate in the bioretention cell occurred mainly in the upper layer of the filler. When the concentration of glyphosate in the runoff was 0.25 or 0.5 mg/L, the concentration of glyphosate degradation products at the two outlets along the way was as much as 26 times higher than that at the lowest outlet. Rainfall events promoted the migration of glyphosate and its degradation products within the filler. Glyphosate and its degradation products in ZLB were mainly distributed at 15 and 25 cm deep in the filler layer, while the highest concentrations in CLB were at 5 and 35 cm. Discontinuous runoff into the bioretention cell leads to continuous leaching and adsorption of glyphosate in the bioretention cell until complete degradation occurs.

EXPLORING ENHANCED SOLAR POND CONFIGURATIONS FOR LOW-GRADE THERMAL ENERGY STORAGE: A COMPARATIVE STUDY

This study revolves around the salt gradient solar pond (SGSP) as an environmentally conscious approach for efficiently storing heat. This investigation assesses the impact of adding a coal cinder (CC) additive and integrating an East–West reflector (EWR) on enhancing the energy efficiency of the salt gradient trapezoidal solar pond (SGTSP). The research involves designing, fabricating, and analyzing SGTSP systems with EWR and CC, comparing them with standard SGTSP systems in terms of energy performance. The results indicate a substantial 43.4% rise in average solar intensity when employing the EWR, and incorporating the coal cinder additive elevates the lower convection zone's (LCZ) temperature by 24.5%. In comparison to the conventional SGTSP (SGTSP-C), the SGTSP with the East–West reflector (SGTSP-EWR) and SGTSP with the coal cinder (SGTSP-CC) attain temperatures of 60.75°C and 66.87°C, respectively, representing an increase of 15.49% and 27.12%. Similarly, the maximum energy efficiency of LCZ for SGTSP-EWR and SGTSP-CC were 27.15% and 55.92% higher than the values of SGTSP-C. Ultimately, this research showcases the thermal energy storage potential of SGTSP and provides practical approaches to improve its energy efficiency.

Mechanical and microstructural properties analysis of one-part geopolymer based on burnt coal cinder replaced by metakaolin

The development of traditional geopolymer for cast-in-situ applications has been a relatively challenging issue due to the difficulties in handling, transporting, and storing of highly corrosive and viscous alkali solutions. This study developed a green, economical, and user-friendly one-part geopolymer, which is formed by mixing burnt coal cinder (BCC), metakaolin (MK), and solid alkali activators such as sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) and cured under elevated temperatures.The effects of parameters such as compressive strength, curing time and temperature, thermal stability, and chemical resistance were investigated. To evaluate the microstructural properties of one-part geopolymers, Brunauer-Emmett-Teller, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, an energy-dispersive spectrometer, and thermogravimetric analysis were employed.The results showed that the optimum preparation conditions were 50:50:15:11.64 (g:g:g:g) for BCC:MK:NaOH: Na2SiO3, with a liquid-solid ratio of 0.30, cured at 80 °C for 24 h and 28 days at room temperature. Significant dissolution and shift of one-part geopolymeric precursors onto the production of new crystalline phases were observed, resulting in more N-A-S-H gel binding substances and the development of properties.Furthermore, the pore size distribution was improved by over 60% compared to their counterparts, and more homogeneity, compactness, and meaningful dense crystal compounds were observed. Despite having the highest compressive strength of 56.61 MPa after 28 days, it substantially declined after exposure to several chemical solutions and thermal stability tests. Therefore, a one-part geopolymer can effectively contribute to ensuring the sustainability of solid waste in the construction industry.

Analysis of portable solar concrete ponds by using coal cinder to trap thermal energy of sustainable building using artificial intelligence

Cinder is a waste product made from the coal residue left over from power plant blast furnaces. Solar energy is a promising renewable energy source, but because of its erratic availability, energy storage technologies must be used. Our research suggests employing coal cinder (CC) to boost the thermal energy stored in transportable solar concrete ponds, combining rock mechanics with renewable energy. The concepts of renewable energy and rock mechanics are combined in this invention. Additionally, because it doesn't release any pollutants into the sky, it is great for low heat applications like building cooling and heating. However, due to its sporadic nature, solar energy requires effective energy storage to be used at night and in cloudy weather. By adding coal cinders to the bottom layer of a solar concrete pond in order to increase its heat energy, this work integrates rock mechanics with sustainable energy. A variety of small-scale research use the standard micro solar concrete ponds. Also offered is a numerical calculation for predicting energy development over a sizable area of a solar pond with a salt gradient. The coal cinders may significantly raise the temperature at the pond's bottom. With a constant temperature differential of 30 °C and 20 °C throughout the gradient layer for two different pond sizes with depths of 1.5 m and 1.0 m, this study provides thermal analysis of a salt gradient solar pond using machine learning as Particle Swarm Optimization (PSO) and extracting heat from the Lower Convective Zone (LCZ). Going through the regression indices (RMSE, R2, r), the energy efficiency (heat) of the first 1.5-meter-deep concrete pond varies between 22.1 and 11.3% throughout the winter. The energy performance of a solar pond decreases dramatically when the non-convective zone thickness and its size are decreased. For the two concrete ponds with depths of 1.5 m and 1.0 m, respectively, the annual average efficiencies are 23% and 16%. Hence, the solar pond demonstrates that it is an effective method for utilizing solar energy and may be a useful option for low-temperature energy needs, such as room heating.

Recycling of granite waste and burnt coal cinder for the preparation of sintered permeable bricks

AbstractThe sintered permeable brick was prepared using granite waste and burnt coal cinder (BCC) as raw materials to ensure the utmost utilization of both solid wastes. The effect of various parameters, such as the proportion of raw materials, granite particle size and sintering temperatures on the properties of the permeable brick were studied, and the relevant sintering mechanism was clarified. The differential scanning calorimetry curves indicate that the mixture of granite waste and BCC begins to melt at a lower temperature, which is lower than the temperature for melting them alone, so the use of them to prepare sintered bricks will reduce energy consumption. The optimal conditions for the preparation of the permeable bricks were determined as the mass ratio of granite waste to BCC of 80: 20, sintering temperature of 1150–1175°C, and granite particle size of .9–1.25 mm. It was found that the permeability and the flexural strength of the samples can reach 3.41 × 10 −2 cm/s and 4.2 MPa, respectively, which both exceed the requirements specified in the national standard of China.

Calcium‐activated geopolymer ceramics: Study of powder calcination and amorphous gel phases

AbstractBurnt coal cinder (BCC), the main solid waste in coal and electric power industries was used to prepare the geopolymer ceramics (GC) in this study. The optimum preparation technology of BCC‐based GC and the effects of calcination and calcification on the compressive strength of BCC‐based GC were studied. Through the calcification of BCC with CaO, NaAlO2 and sodium silicate solution (SS) were separately used as the co‐activator and silica additive to prepare BCC‐based GC. The optimal single‐factor conditions determined by the experiment were BCC:CaO:NaAlO2:SS = 18:3:2:4 (g:g:g:mL) and the liquid–solid ratio was 0.46. The compressive strength of BCC‐based GC was 32.78 MPa (28 days). It was obtained that the calcination of calcified BCC below the temperature of 1000°C can effectively remove the fixed carbon in BCC but will destroy amorphous active aluminosilicate. The microstructure study showed that BCC reacted in the ternary system of Ca–Al–Si to form a variety of amorphous products (C–(A)–S–H and (N, C) –A–S–H). Along with the three‐dimensional amorphous gel structure as the dominant phase, the coexistence and interlacing of various amorphous gels made the microstructure more compact and increased the compressive strength of the BCC‐based GC. GCs with various amorphous phases have been successfully prepared at low temperature, and it also provided a new idea for the utilization of low‐activity silicate solid wastes.

Black coal cinder ceramics: an unusual technological choice in Sichuan Province, China

In Sichuan Province, China, many workshops on the historic pottery street of Yingjing and one small one in Gaoxian produce black pottery by adding ground coal cinders to their clay. This unique raw material is fired with a kiln design and process that are also unique. Coarse-grained cooking products are most common, but fine-grained teawares and other new product lines recently emerged in Yingjing to meet new market niches. High-temperature phases such as mullite, cristobalite, and glass seen in thin sections primarily reflect those also seen in the coal cinders. The volume of closed and open pores and the structure of pore systems differ for coarse versus fine wares and are well suited for intended product functions. Variation in pore systems for Yingjing coarse wares indicates subtle differences in raw materials, materials preparation, and firing temperatures between workshops and within each workshop’s numerous production runs and products compared with the sole Gaoxian small workshop with very limited products.

The combined effects of calcium oxide and phosphate on burnt coal cinder-based cementitious materials

Coal and electric power industries generate a large amount of burnt coal cinder (BCC). Due to the low activity of BCC, its practical utilization is highly limited. In this paper, the preparation of cementitious materials (CM) by BCC was studied to improve the utilization rate of BCC. After calcification of BCC with CaO, Na3PO4·12H2O (TSPH) and sodium silicate solution (SS) were separately used as the co-activator and silica additive to prepare BCC-based CM. The optimal single factor conditions determined by the experiments were BCC: CaO: TSPH: SS = 18:4:3:2 (g: g: g: mL) and a liquid–solid ratio of 0.30 and the compressive strength of BCC-based CM with 45.53 MPa (28 d) could be obtain. Moreover, the absorption of P was inhibited under the condition of sufficient exogenous Si by single factor experiment and response surface methodology. The microstructure study showed that the gel phases formed by the reaction of BCC in the ternary system of Ca-Si-P were more abundant and homogenous distributed. Furthermore, as the formation of the Si-Al-P gel structure, the coexistence and interlacing of various gels resulted in a more compact microstructure and significantly increased the compressive strength of the BCC-based CM. Low-activity BCC as the raw material of CM could reduce the harm of solid waste to the environment and benefit the green development of the construction industry.

Enhanced nickel removal and synchronous bioelectricity generation based on substrate types in microbial fuel cell coupled with constructed wetland: performance and microbial response.

In this study, an attempt was made to clarify the impact of substrates on the microbial fuel cell coupled with constructed wetland (CW-MFC) towards the treatment of nickel-containing wastewater. Herein, zeolite (ZEO), coal cinder (COA), ceramsite (CER), and granular activated carbon (GAC) were respectively introduced into lab-scaled CW-MFCs to systematically investigate the operational performances and microbial community response. GAC was deemed as the most effective substrate, and the corresponding device yielded favorable nickel removal efficiencies over 99% at different initial concentrations of nickel. GAC-CW-MFC likewise produced a maximum output voltage of 573mV, power density of 8.95 mW/m2, and internal resistance of 177.9 Ω, respectively. The strong adsorptive capacity of nickel by GAC, accounting for 54.5% of total contaminant content, was mainly responsible for the favorable nickel removal performances of device GAC-CW-MFC. The high-valence Ni2+ was partially reduced to elemental Ni0 on the cathode, which provided evidence for the removal of heavy metals via the cathodic reduction of CW-MFC. The microbial community structure varied considerably as a result of substrates addition. For an introduction of GAC into the CW-MFC, a remarkably enriched population of genera Thermincola, norank_f__Geobacteraceae, Anaerovorax, Bacillus, etc. was noted. This study was dedicated to providing a theoretical guidance for an effective regulation of CW-MFC treatment on nickel-containing wastewater and accompanied by bioelectricity generation via the introduction of optimal substrate.

Heavy metal contamination in beach sediments as a result of sewage outlet and waste residue dumping in Qingdao, China.

Heavy metal pollution on beaches due to enhanced human activities has received attention. This study takes four beaches in China as examples to study the characteristics of heavy metal pollution. The results show that most beach sediments have a certain degree of heavy metal accumulation as a result of human activities, except for the sediments of No. 1 beach. The beaches in order of the degree of pollution were No. 3 beach > Shilaoren beach > No. 2 beach > No. 1 beach. Three of the four studied beaches show contamination with As, Cr, Fe, Ni, Pb and Zn. Sewage outlets are the main sources of these pollutants, but the high levels of Zn and Fe are caused by coal cinder dumping at one beach, and the high levels of Ni are due to the coating of fishing boats at another beach. Heavy metal pollution occurs in areas near pollutant sources or at the high or low tide lines due to waves and tides. Heavy metals also diffuse vertically, resulting in contamination at certain depths. The distribution of heavy metals over ten years showed that most of the pollutants on cape-bay beaches are difficult to diffuse outward, which indicates that a special pollutant management plan needs to be developed for such beaches.

Waste coal cinder catalyst enhanced electrocatalytic oxidation and persulfate advanced oxidation for the degradation of sulfadiazine.

Waste coal cinder, a kind of waste cinder discharged from coal combustion of thermal power plants, industrial and civil boilers, and other equipment, was rich in metal oxides with catalytic activity. In this work, waste coal cinder was used to enhance electrochemical coupling peroxymonosulfate (PMS) advanced oxidation degradation of sulfadiazine (SD). The surface morphology, elemental composition, and electrocatalytic activity of waste coal cinder were characterized by various characterization instruments. The results show that compared with simple electrocatalytic oxidation, electrocatalytic oxidation+waste coal cinder and electrocatalytic coupled persulfate oxidation, electrocatalytic oxidation+PMS advanced oxidation+waste coal cinder has the largest removal efficiency (99.95%) and mineralization rates (90.16%) of SD in 90min, indicating that the introduction of waste coal cinder greatly increases the degradation efficiency. •OH and SO4-• were detected during the process of degradation. The optimal degradation process parameters were explored through different voltage, pH, plate spacing, aeration flow rate, potassium peroxymonosulfate sulfate complex salt dose, and Na2SO4 dosage. Cycling experiments show waste coal cinder has good structural stability. Through the analysis of triple quadrupole liquid chromatography-mass spectrometry (LC-MS), we put forward three possible ways of SD degradation. This research will provide a novel vision for water treatment.

Waste Coal Cinder Catalyst Enhanced Electrocatalytic Oxidation and Persulfate Advanced Oxidation for the Degradation of Sulfadiazine

Waste Coal Cinder Catalyst Enhanced Electrocatalytic Oxidation and Persulfate Advanced Oxidation for the Degradation of Sulfadiazine

Analyses of deodorization performance of mixotrophic biotrickling filter reactor using different industrial and agricultural wastes as packing material

In this study, to efficiently remove malodorous gas and reduce secondary pollution under mixotrophic conditions, pine bark, coal cinder, straw and mobile bed biofilm reactor (MBBR) fillers were used as packing materials in a biological trickling filter (BTF) to simultaneously treat high-concentration H2S and NH3. The results showed that the removal rate of BTF-A filled with pine bark was the highest, which was 86.31% and 94.06% under the H2S and NH3 loading rates of 53.59 g/m³·h while the empty bed residence time (EBRT) was 40.5 s. The theoretical maximum load was obtained by fitting the kinetic curve, and the value were 90.09 g H2S m-³·h−1 and 172.41 g NH3 m-³·h−1. Meanwhile, after treating with 720 ppm of NH3, the average concentration of NO3- in the BTF circulating fluid was only 127.58 mg/L, indicating the better performance of secondary pollutants control. Microbiological analysis showed that Dokdonella, Micropruina, Candidatus_Alysiosphaera, Nakamurella and Thiobacillus possessed high abundance at the genus level, and their entire percentage in four BTF reactors were 62.87%, 46.32%, 47.98%, and 57.35% respectively. It is worthwhile that the genera Comamonas and Trichococcus with heterotrophic nitrification and aerobic denitrification capabilities and proportion of 3.66%, 1.45%, 5.43%, and 3.23% were observed in four reactors.

Preparation and characteristics analysis of an ecoenvironmental protection cyclic solidification dust-fixing agent extracted from waste shrimp shells to suppress dust in coal resource-based cities

There are a lot of coal cinder and dust in the development of coal resource-based cities. Improper handling will cause dust flying, which has a great impact on urban residents and the environment. The purpose of this research is to follow the principle of waste recycling, to use waste shrimp shells to extract chitosan as a raw material, to carry out graft polymerization with acrylic acid and polyvinyl alcohol-1788, and to carry out amidation crosslinking reactions with ethylenediamine tetraacetic acid to produce products. The results showed that the degree of deacetylation of chitosan reached 85% with the optimized extraction method, which greatly shortened the process cycle. Through orthogonal experiments and osmotic wetting experiments, the best preparation process was determined. The reaction process, structure of the product and adhesive structure of the solidified layer were analyzed by FTIR, XPS and SEM. The thermal stability of the product was analyzed by thermogravimetry. Relevant performance tests showed that the product had good adhesion with dust, the hardness of the solidified layer could reach 98 HA, and the dust fixation rate was 92.67% when the wind speed was 15–18 m/s. It has the advantage of circulating dust fixation, which improves the utilization rate of resources.

Recycling of construction and demolition waste to fabricate cost-effective anorthite ceramic membranes for enhanced separation of an oil-in-water emulsion

The recycling of construction and demolition waste to prepare cost-effective anorthite membranes was demonstrated by the in-situ synthesis of anorthite. The effects of sintering temperature and calcium loading on the physical properties (porosity, phase composition, microstructure, pore size, nitrogen permeation, and tortuous factor) of the as-synthesized porous membrane were investigated in detail. With the addition of coal cinder and natural bauxite, the anorthite phase was synthesized at 878 °C. Almost all samples had a high porosity of >35% at 900 °C–1000 °C. With the increasing temperature, the porosity of the samples (except for P2 and P4) decreased gradually to close to zero. The variation trend of pore size was consistent with that of the mass fraction of calcium-containing crystals. This occurred because the growth of these crystals as a sintering neck led to the expansion of the pore structure. The increasing temperature caused a decrease of the tortuous factor and an increase of permeance. Due to the presence of anorthite, the as-synthesized membrane became hydroxylated by the alkali-solution treatment and manifested improved hydrophilicity, resulting in an enhanced separation of the oil-in-water emulsion.

Experimental Investigation on Mixed Combustion Characteristics of Coal, Tobacco Straw, and Cinder in an Energy-Saving Bake Process

Abstract In view of high-energy consumption, high baking cost, and serious pollution emission during the baking process of tobacco leaves, thermogravimetric analysis is employed to investigate the combustion characteristics of coal, tobacco straw, and cinder. Analyzing thermogravimetric-derivative of thermogravimetric (TG-DTG) characteristics of samples with different blending ratios and based on the ignition temperature and burnout temperature, the combustion characteristics of the samples are obtained. Compared with the individual combustion of coal, the blending ratio of the optimal positive effect is obtained. It is illustrated that different blending ratios of coal, tobacco straw, and cinder result in different effects between promotion and inhibition. Tobacco straw is beneficial to burn on fire but adverse to keep combustion of fixed carbon. Compared with the TG and DTG characteristics in different blending ratios of coal, tobacco straw, and corresponding combustion characteristic parameter, it is illustrated that the best blending ratio of tobacco straw is 40%. According to the TG and DTG characteristics of different blending ratios of coal, cinder, and corresponding combustion characteristic parameter, it is shown that the more blending ratio of cinder, the more adverse effect to fixed carbon burning. The composite fuels with 40% tobacco straw, 10% coal cinder, and 50% coal have two obvious advantages. On the one hand, it can maintain quick burning and the volatile combustion of the tobacco straw at low-temperature stage. On the other hand, it can keep continuous combustion of the fixed carbon in coal at high-temperature stage.

ASSESSMENT OF NATURAL RADIOACTIVITY LEVELS AND RADIOLOGICAL HAZARDS IN BUILDING MATERIALS

Radioactivity of 226Ra, 232Th, and 40K were measured in a total of 92 samples, including eight commonly used types of building materials that were obtained from local manufacturers and suppliers in Beijing. Concentrations were determined using high-purity germanium gamma-ray spectrometry. The 226Ra, 232Th, and 40K activity concentrations in all samples varied from 10.1 to 661, 3.3 to 555 and 3.2 to 2945Bq per kg with an average of 127.8, 114.8, and 701.5Bq per kg, respectively. The potential radiological hazards were estimated by calculating the absorbed dose rate (D), radium equivalent activity (Raeq), external hazard (Hex), and internal hazard (Hin) indices. The investigated building materials were classified into different types according to the radioactivity levels. Results from this research will provide a reference for the acquisition, sales, and use of building materials. Attention should be paid to the use of coal cinder brick, ceramic, and granite in the construction of dwellings.

High-porosity whisker-mullite/corundum membrane support prepared from recycled industrial waste coal cinder

Recycled coal cinder was utilized as a raw material for the preparation of a high-porosity and low-cost whisker-mullite/alumina membrane support via in situ synthesis of mullite whiskers with MoO3 and AlF3 as additives. The effects of the sintering temperature and additives on the physical properties (porosity, shrinkage, phase composition, microstructure, pore size, nitrogen permeation, and tortuosity factor) of the porous mullite-based membrane supports were investigated in detail. Based on the synergistic effect of AlF3 and MoO3, the porosity of the as-synthesized membrane supports was as high as 60%. This is attributed to the reduction in the viscosity of the solid phase reaction interface between the mullite precursors by the MoO3 additives, thus promoting the formation of mullite grains, while the AlF3 additive effectively promoted the anisotropic growth of whisker-mullite via vapor deposition. This whisker-mullite membrane support with a cross-interlocking structure has an inherently unimodal pore-size distribution and low tortuosity factor (~0.4).

Contamination level and potential health risk assessment of hexavalent chromium in soils from a coal chemical industrial area in Northwest China

This study aimed to evaluate the total Cr and Cr(VI) contamination levels and assess the possible health risk of Cr(VI) in soils from a coal chemical industrial area in Northwest China. The contamination factor (CF) was used to calculate the total Cr and Cr(VI) contamination levels in soils from the study area. The highest concentration of Cr(VI) (69.58 mg/kg) was found in the top soil (0–20 cm) with the distance of 10 m to the coal cinder heap. The carcinogenic risk (CR) and hazard quotient (HQ) were estimated for health risk to workers by using “Chinese Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014).” The results showed that the soils from the study area were moderately polluted by the total Cr and Cr(VI). There was no serious non-CR (HQ < 1). However, the CR values of Cr(VI) were significantly higher than the threshold value, indicating that workers are facing serious threat of Cr(VI). Inhalation (70.32%) was the main exposure pathway to CR, followed by dermal contact (20.64%), and then ingestion (9.04%). These results provide basic information of Cr(VI) pollution control and environment management in coal chemical industrial areas.

Coal Combustion Synthesis of Coal Cinder-Supported TiO2 with Commendable Photocatalytic Activity

Coal cinder-supported TiO2 photocatalysts were synthesized via a novel coal combustion method. As-obtained samples were characterized by XRD, SEM, EDS mapping, Raman spectra, FTIR and DRS, and their photocatalytic performances were evaluated by degradation of methylene blue (MB) and methyl orange (MO) under UV–Vis light illumination. The results revealed that mixed-phases TiO2 with adjustable anatase–rutile ratio could be obtained by adjusting the amount of precursor tetrabutyl titanate, which was uniformly covered on the coal cinder. These coal cinder-supported TiO2 photocatalysts exhibited commendable photocatalytic activity. Among them, the indexed CCT-7.5 sample presented the maximum of activity, which can be attributed to the optimal phase composition of TiO2. The present work provided a novel synthetic route to fabricate immobilized photocatalysts, which might be extended to the preparation of other functional materials.