Low Energy Consumption Method Research Articles

Experimentation and thermo-enviro-economic analysis of solar still coupled with large-capacity heating and cooling units

Solar still is a water desalination method that works by the principle of evaporation and condensation, which has been adopted earlier as a simple and low energy consumption method. However, it suffers from low reliability and poor performance. Hence, the current study provides a developed solar still combined with a heat pump and an evacuated tube water heater to augment the thermal processes. The heat pump was attached to advance the condensation process. Besides, the heater was combined with the system to afford a storage medium and boost the evaporation process. Firstly, a parametric analysis was performed in order to select a suitable water recirculation rate and operating temperature. The productivity increased linearly with the temperature by a rate of about 0.035 L/h/m2 for a 1 ℃ temperature rise until below 68 ℃; then, the relation becomes exponential where the productivity increased by 0.16 L/h/m2 after a 1.5 ℃ temperature rise. Daily, the modified design exhibited productivity, energetic efficiency, and exergetic efficiency of 13.38 L/m2, 44.12 %, and 4.17 %, respectively. Furthermore, including cover cooling boosted these findings to 14.22 L/m2, 47.79 %, and 4.69 %, which were higher than that of a basic distiller by 291.73, 16.05, and 30.28 %, respectively. From the cost perspective, the minimum distilled water price was obtained at a 20-year lifetime span and a 5 % interest rate of 0.0121 $/L.

Effects of tannin acid impregnated pretreatment on dimensional stability and chemical composition of heat-treated Chinese fir

Abstract Thermal treatment is an effective method for improving the dimensional stability of wood; however, it typically requires high temperatures. To achieve low-temperature heat treatment, this study employed wood samples impregnated with 10 % tannin acid (TA) and examined their changes in dimensional stability and chemical components after heat treatment at various initial moisture content levels. The results revealed that the TA-10 %-HT group exhibited enhanced dimensional stability. Specifically, both the tangential and radial moisture swelling decreased by 21.7 % and 11.8 %, respectively. FTIR and XRD analysis indicated that the presence of tannin acid catalytically facilitated the degradation of hemicellulose. Moreover, an increase in moisture content resulted in the ionization of TA, amplifying acidity and further affecting cellulose degradation. TGA demonstrated that TA impacted the thermal stability of heat-treated materials by lowering the initial decomposition temperature of wood components and increasing the residual weight of wood. Overall, pretreatment with TA impregnation and moisture content significantly improved the dimensional stability of Chinese fir wood and altered its chemical composition. This approach holds considerable potential for enhancing wood properties through a low-energy consumption method during the heat treatment process, expanding the practical application of wood.

Enabling efficient and economical degradation of PCDD/Fs in MSWIFA via catalysis and dechlorination effect of EMR in synergistic thermal treatment

Catalytic thermal treatment is an efficient and low-energy consumption method for degrading polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in municipal solid waste incineration fly ash (MSWIFA). However, catalysts with high activity are expensive, difficult to separate and reuse from the treated MSWIFA, and they usually pose a risk of heavy metal pollution. Herein, a synergistic thermal treatment method of MSWIFA and electrolytic manganese residue (EMR) at relatively low temperatures was proposed after an in-depth analysis of their mineralogy composition to achieve detoxification of PCDD/Fs in MSWIFA. The mass and WHO-TEQ degradation efficiencies of PCDD/Fs significantly increased from −92.79% and −51.46%–98.57% and 96.10%, respectively, by the addition of electrolytic manganese residue (EMR) with an MSWIFA/EMR ratio of 3:7 in the thermal treatment of MSWIFA at 250 °C for 60 min. The WHO-TEQ concentration of PCDD/Fs in the treated sample decreased to 3.7 ng WHO-TEQ/kg, meeting the European end-of-waste criteria (20 ng WHO-TEQ/kg). The excellent degradation effect of EMR on PCDD/Fs in MSWIFA could be attributed to two aspects: 1) the manganese oxides in EMR has a catalytic effect on the degradation of PCDD/Fs; 2) the NH3 generated by the decomposition of (NH4)2SO4 in EMR is conducive to the degradation and resynthesis inhibition of PCDD/Fs. Besides, the thermodynamic calculations indicated that CaClOH in MSWIFA played a crucial role in the decomposition of (NH4)2SO4 in EMR. In addition, the degradation pathways and mechanisms of PCDD/Fs-homologues under the synergistic effect of manganese oxides, ammonia, and thermal field were investigated through comparative analysis of concentration and fingerprint of PCDD/Fs.

Bulk‐Size and Highly Transparent Composite Phosphor for NIR Spectroscopy

AbstractNear‐infrared (NIR) phosphors offer a novel luminescent solution for NIR spectroscopy, but their efficiency remains low. Herein, it is demonstrated that the high transparency of a phosphor improves its external quantum efficiency by developing a new inorganic–organic composite phosphor. The new bulk‐size and highly transparent composite phosphor is fabricated through layer‐by‐layer assembly of micron‐sized hexagonal LiSrAlF6:Cr3+ powder phosphor. The inline transparency of the final bulk phosphor can be controlled from 0% to 90.2% at a large solid concentration of ≈47 vol.%. With high transparency, the new bulk phosphor allows the phosphor‐conversion light‐emitting diode (pc‐LED) a 2.9 times improvement in efficiency. This paper inspires a feasible and low energy consumption method to facilitate next‐generation NIR pc‐LED phosphors.

Pilot-scale study of step-feed anaerobic coupled four-stage micro-oxygen gradient aeration process for treating digested swine wastewater with low carbon/nitrogen ratios

This study developed an innovative step-feed anaerobic coupled four-stage micro-oxygen gradient aeration process to treat digested swine wastewater. An anaerobic zone was used for prepositive denitrification; four micro-oxygen reactors (zones O1–O4) were used for simultaneous partial nitrification and denitrification through low-dissolved oxygen gradient control, step-feed, and swine wastewater-digested swine wastewater distribution. The nitrogen-removal efficiency was satisfactory (93 ± 3 %; effluent total nitrogen, 53 ± 19 mg/L). Mass balance coupled with quantitative polymerase chain reaction analysis revealed that simultaneous partial nitrification and denitrification was achieved in four micro-oxygen zones. Zones O1 were the major denitrification zones for nitrogen removal; nitrification was primary happened in zones O2 and O3. Correlation analysis confirmed that low-dissolved oxygen gradient control was the key to achieving efficient nitrogen removal. This study provides a low oxygen energy consumption method to treat digested swine wastewater with a low carbon/nitrogen ratio (<3).

Lignin-derived carbon quantum dots/Ni-MOL heterojunction from red phosphorus-assisted ball milling pretreatment and their application in photocatalysis: An insight from experiment and DFT calculation

The constructing defects by doping phosphorus elements are limited by high energy consumption, environment pollution and long preparation time. In this work, lignin-derived carbon quantum dots/nickel metal-organic layer (Ni-MOL) heterojunction was successfully prepared by red phosphorus-assisted ball milling pretreatment . And the application in photocatalytic tetracycline (TC) degradation have been investigated systematically by the combination of the calculational and experimental methods. The maximum degradation rate was 98.98% for P(1.0)-CD/Ni-MOL in 120 min under visible light condition. P-doping was beneficial to reduce the electron transport resistance. Moreover, it increased the hydrophilicity but reduced the position of conduction band, thus more active •O 2 - for TC degradation were generated. Hence, the novel photocatalyst prepared by the simple and low energy consumption method is expected to treat TC wastewater effectively and this work makes a contribution to the perfection of P-doped photocatalysts. • Red phosphorus-assisted ball milling pretreatment were firstly used to prepare P-CD/Ni-MOL photocatalyst. • P-doping can reduce electron transport resistance, increase the hydrophilicity and reduce the position of conduction band. • Tetracycline can be rapidly and thoroughly degraded in water by P-CD/Ni-MOL.

Current Advances in Biodegradation of Polyolefins.

Polyolefins, including polyethylene (PE), polypropylene (PP) and polystyrene (PS), are widely used plastics in our daily life. The excessive use of plastics and improper handling methods cause considerable pollution in the environment, as well as waste of energy. The biodegradation of polyolefins seems to be an environmentally friendly and low-energy consumption method for plastics degradation. Many strains that could degrade polyolefins have been isolated from the environment. Some enzymes have also been identified with the function of polyolefin degradation. With the development of synthetic biology and metabolic engineering strategies, engineered strains could be used to degrade plastics. This review summarizes the current advances in polyolefin degradation, including isolated and engineered strains, enzymes and related pathways. Furthermore, a novel strategy for polyolefin degradation by artificial microbial consortia is proposed, which would be helpful for the efficient degradation of polyolefin.

High-gravity intensified electrodeposition for efficient removal of Cd2+ from heavy metal wastewater

Efficiently treating heavy metal wastewater are the goal that industries pursuit. A novel Multi-concentric Cylindrical Electrodes-Rotating Bed (MCCE-RB) which could provide high-gravity fields was proposed to enhance electrodeposition for efficient treatment of Cd-containing wastewater in this paper. Under the optimal operating conditions covering current density of 53.1 A m−2, wastewater circulation flowrate of 64 L h−1, high-gravity factor of 15, NaCl concentration of 0.2 mol L−1, initial pH value of 2, and initial Cd2+ concentration of 800 mg L−1, the removal efficiency of Cd2+ reached 99.4% after 120 min electrodeposition. Compared with the results of electrodeposition in normal gravity field, the removal efficiency of Cd2+, current efficiency and the mass of deposits were increased by 18.4%, 15.7% and 35.4%, respectively. The cell voltage, electrodeposition time and total energy consumption (ETotal) were decreased by 21.7%, 42% and 21.2%, respectively. SEM, EDS, XRD and XPS analyses showed that the deposits were flaky and layered structure in high-gravity fields, avoiding the formation of dendrite in normal gravity field. The deposits were comprised of the mixture of Cd and Cd(OH)2, and the percent weight of elemental Cd was 91.29% in the high-gravity field which was 19.17% higher than that in normal gravity field. The purity of Cd was improved in the high-gravity field. These was ascribed to the depressed hydrogen evolution reaction, the removal of gas bubbles from the electrodes and the improvement in mass transport in the optimal high-gravity field. High-gravity intensified electrodeposition could serve as a clean, high efficient and low energy consumption method for treating heavy metal wastewater.

Scalable method for preparing multi-walled carbon nanotube supported red phosphorus nanoparticles as anode material in lithium-ion batteries

Nanoscale red phosphorus (RP) has attracted plenty of interest as an anode material for lithium-ion batteries (LIBs). However, current methods for preparing RP nanocomposite are energy intensive and dangerous. Here, we report a scalable method for preparing multi-walled carbon nanotube supported RP nanoparticles (RP NPs/MWNT) composite. RP lump is dissolved in ethylenediamine. Then RP NPs were generated after adding HCl. Through this environmentally safe and low energy-consumption method, uniform RP NPs (5 nm) are deposited on MWNT, forming RP NPs/MWNT composite. Such small RP particles buffer volume expansion and MWNT accelerates electron transfer during cycling, therefore enabling RP NPs/MWNT to deliver a high initial reversible capacity of 1780.2 mAh g−1 and a high capacity retention of 88.6% at 200 mA g−1 after 100 cycles. Our method can be applied to synthesizing various RP nanocomposites for LIBs and is easy to set up, inexpensive, rapid, accessible to factory.

Effect of different carbon allotropes on optical properties of CoCuMnOx solar selective coating

This study investigates the inclusion of different forms of carbon in CoCuMnOx solar selective coating via the low-energy consumption method “sol-gel technique”. The usage of carbon as an additive in CoCuMnOx was an attempt to enhance the spectral selectivity. Four allotropes of carbon (graphene nanoplatelets (GNP), carbon nanotubes (CNT), graphite, and charcoal) were embedded in the selective coating with different concentrations and then were deposited on smooth and roughened stainless-steel sheets. In an additional attempt to improve CoCuMnOx selectivity, three different coatings (silica, charcoal@silica, and CNT@silica) were individually applied on top of it. Each carbon allotrope showed distinct structural and optical properties of the coating. Using charcoal as an additive achieved a solar absorptance of 0.964 and a thermal emittance of 0.095, thus providing superior optical properties compared to the other allotropes. The characteristics of the coatings were detected by X-ray diffraction, Energy Dispersive X-Ray analysis, and Scanning Electron Microscope.

Research progress on the formation mechanism of azeotrope and its separation process in microwave field

AbstractIn the process of petrochemical, coal chemical, and pharmaceutical industries, a large amount of azeotrope is usually produced. The traditional method of separating azeotrope consumes a lot of energy. Therefore, it is of great significance to develop a low energy consumption and high efficiency method of separating azeotrope to achieve economic benefits and reduce energy consumption. The use of microwave fields for enhanced distillation processes to separate azeotrope is currently of great interest. In this paper, the mechanism of azeotropic formation is reviewed from three aspects: experimental studies, quantum chemical calculations and molecular simulations, and the influence of cluster structure on azeotropic formation is analyzed. Then the paper discusses the experimental study of microwave‐enhanced distillation process to separate azeotrope and the molecular simulation process, and the mechanism of microwave‐assisted azeotropic separation and the feasibility of industrialization are analyzed. © 2021 Society of Chemical Industry (SCI).

One-step in-situ synthesis of Bi-decorated BiOBr microspheres with abundant oxygen vacancies for enhanced photocatalytic nitrogen fixation properties

The conversion of atmospheric nitrogen (N2) to ammonia (NH3) under mild conditions is quite challenging due to high stability of the triple covalent bond. Here we report that Bi-decorated BiOBr microspheres with plentiful oxygen vacancies (OVs) were successfully fabricated by one-step solvothermal strategy and used as effective photocatalysts for nitrogen fixation. The metallic Bi was reduced in-situ by glycerol and deposited on the surface of BiOBr microspheres. The synchronously generated OVs can serve as the activation center for nitrogen. Compared to pure BiOBr, Bi@BiOBr hetero-structured microspheres have higher specific surface area, superior visible-light utilization, more effective separation of photoexcited charge carriers, thus exhibiting more pronounced visible light photocatalytic N2 fixation performance. Specifically, the N2 reduction rate of the Bi@BiOBr-2 is 1350 μmol g−1 h−1, which is 11.8 times higher than pure BiOBr (114 μmol g−1 h−1). This study provides a simple and low energy consumption method for effective and stable photocatalytic N2 fixation.

Facile, green and energy-efficient preparation of fluorescent carbon dots from processed traditional Chinese medicine and their applications for on-site semi-quantitative visual detection of Cr(VI)

Green synthesis of fluorescent carbon dots (CDs) from biological sources have attracted much attention because of their low cost, excellent bio-compatibility and renewability. However, previously reported synthesis strategies of biomass-derived CDs were commonly involved in the sophisticated equipment, high energy consumption and complicated synthetic conditions, restricting their practical application in various fields. In this work, a green, facile and low energy consumption method was demonstrated to prepare highly fluorescent CDs through room temperature one-step solvent extraction from rice fried Codonopsis pilosula (CP) which could be easily obtained commercially. The obtained CP-CDs exhibited outstanding fluorescence property (quantum yield up to 12.8 %) and high photostability. Besides, CP-CDs showed high selectivity and sensitivity of fluorescence response to Cr(VI) over a broad range of 0.03−50 μM and a satisfactory detection limit of 15 nM. The developed sensing system was applied to quantitative determination of Cr(VI) in environment water samples and industrial sewage successfully with good recovery and high precision. More interestingly, CP-CDs based fluorescent hydrogel sensor was further fabricated for on-site semi-quantitative visual Cr(VI) detection in industrial sewage, demonstrating their tremendous potential for the fast and low-cost monitoring of Cr(VI) in industrial discharges.

Eco-production of silica from sugarcane bagasse ash for use as a photochromic pigment filler

Sugarcane bagasse is a significant renewable energy source for the sugar and bioethanol industries. Bagasse ash is the waste from the combustion process and is mostly disposed of as landfill. Only a small quantity of bagasse ash is utilized as pozzolan in concrete, and a considerable quantity is left unused due to its high carbon and crystallite content. Generally, bagasse ash is rich in silica (SiO2), and it is thus an alternative source for silica extraction. In this paper, a low-energy and low-chemical consumption method is proposed to obtain silica from bagasse ash using alkali extraction and acid precipitation. The physical and chemical properties of the extracted silica are described. A silica yield of 80% and moisture absorption of 73% were achieved. The silica had amorphous phases and was light gray in color owing to the presence of carbon from incomplete combustion. Bagasse silica was used as an extender filler in an expensive photochromic pigment to increase the bulk volume. It was found that a pigment-to-silica mass ratio up to 1:10 could be used for thick-layer painting. However, a ratio of up to 1:3 is recommended for thin-layer screen-printing on fabrics. The bagasse ash silica-pigment blends have very good color fastness when washing; however, frequent aggressive washing should be avoided.

A novel integrated process to convert cellulose and hemicellulose in rice straw to biobutanol

A novel integrated process was established in this study to produce butanol from rice straw. In the first pretreatment, an alternative NaOH/Urea preatment operated at −12 oC efficiently removed 10.9 g lignin and preserved 91.54% cellulose and hemicellulose in 100 g rice straw. Subsequently, crude cellulase produced from Trichoderma viride was used to convert pretreated rice straw to mono-sugars for fermentation. The yields of glucose, xylose and arabiose obtained from 100 g rice straw were 31 g, 13.4 g and 0.48 g, respectively, resulting in a 69.45% saccharification efficiency of crude enzyme. Finally, to alleviate the carbon catabolite repression (CCR) and enhance butanol production, the coculture system of Clostridium beijerinckii and Saccharomyces cerevisiae was applied. Compared to monoculture of C. beijerinckii F-6, more sugars were consumed, especially the reduction rate of xylose reached to 81.87%, 32.99% higher than that in monoculture system. With more substrate facilitied into metabolism, the butanol concentration reached to 10.62 g/L corresponding to 0.28 g/g substrate, 115.38% higher than that in monoculture system. Overall, this integrated process was a low-energy consumption and efficient method for butanol production from rice straw.

A silica aerogel synthesized from olivine and its application as a photocatalytic support

This study investigates the performance of a silica aerogel-based air purifying coating to functionalize building materials. The air-purifying function comes from an increased photocatalytic activity when the photocatalyst is supported on a silica network with a large specific surface area like silica aerogels. In this study, silica aerogel was first synthesized with a low energy-consumption method from olivine via ambient pressure drying and was applied as a support to load photocatalytic anatase crystals. The silica aerogel production includes sol-gel synthesis, ion-exchange, surface modification and ambient pressure drying. The produced silica aerogel obtained a high specific surface area (694 m2/g) and pore volume (2.99 cm3/g), with a uniform pore size distribution and mesoporous structure. Titania was loaded onto the prepared silica aerogel through a precipitation method. The resulting samples were characterized by measuring the conversion efficiency to oxidize nitric oxide under UV-light irradiation, nitrogen physisorption and FTIR. The silica aerogel coating with titania crystals had a photocatalytic activity of 99.6%, showing it to be a promising photocatalyst in the built environment.

Comparison of different extraction methods for polysaccharides from Crataegus pinnatifida Bunge

In this study, different extraction methods of polysaccharides from Crataegus pinnatifida Bunge (CPP) were compared by studying the extraction yield, structural characteristics and antioxidant activities. Firstly, polysaccharides were obtained using hot water extraction (CPPh), ultrasound assisted extraction (CPPu), enzyme assisted extraction (CPPe) and enzyme-ultrasound assisted extraction (CPPc), respectively. Meanwhile, the optimum extraction conditions of enzyme-ultrasonic assisted extraction were determined by response surface method (RSM). The extraction yields, structural characteristics and antioxidant activities were investigated and compared by visual photos, gas chromatography, ultraviolet-visible and Fourier-transform infrared spectroscopy. The results clearly showed that enzyme-ultrasonic assisted extraction possessed the highest extraction yield (10.39 ± 0.04%). The molecular weight of CPPh was the highest while the other polysaccharides had no significant difference. Besides, the monosaccharide composition of CPPc, CPPh, CPPu and CPPe were similar but the molar percentages of monosaccharide were different. Finally, the results of antioxidant activities showed that CPPc exhibited the highest scavenging effect of superoxide radical and lipids inhibiting ability. In summary, enzyme-ultrasonic assisted extraction was a high-efficient and low-energy consumption method for CPP extraction.

Screening of bacteria for coal beneficiation

Biobeneficiation is considered to be a clean coal technology as an alternative method to reduce sulfur and ash content present in coal by using microbes, in particular bacteria. Recent studies have demonstrated that bacteria can oxidize iron and reduced sulfur compounds present in coal because they promote the oxidative conversion of the reduced forms of sulfur to soluble, easily washed-out compounds. Moreover, the use of bacteria in coal beneficiation has the following advantages, such as simple operation, extensive installation, performed under the mild condition without harmful product, low energy consumption and eco-friendly method. Hence, this study dealt with the investigation of the bacteria capable of oxidizing iron and sulfur compounds and also reducing ash content present in coal. Nine bacteria isolated from mercury-contaminated gold mine sites in Bandung, West Java Province, Indonesia were screened for their ability to oxidize iron and sulfur compounds and reduce ash content. Of the nine bacteria studied, two bacteria (i.e., Pseudomonas plecoglossicida and Pseudomonas hibiscicola) were able to oxidize iron and sulfur compounds and reduce ash content at pH of ~4. The findings of this study provide evidence that both bacteria could be employed as an oxidizing agent that will be applicable for the beneficiation of coal.

High efficient Sr/S isolation for preparing Sr(OH)2 from celestite (SrSO4) in alkaline solution

The bottleneck of strontium compounds preparing from celestite is the promotion of Sr/S isolation efficiency. Low energy consumption and zero release method for isolating Sr/S in preparing Sr(OH)2 process from celestite in mild condition was described. Sr element remained in precipitation with formation of Sr(OH)2, while S element entered into leachate with formation of Na2SO4. The effects of initial concentration of NaOH, conversion temperature, liquid-to-solid (L/S) ratio and conversion time on Sr/S ratio of samples for celestite conversion were systematically investigated by experiments. The results demonstrated that the efficiency of Sr/S isolation increased with the initial concentration of NaOH, L/S ratio and conversion time, and decreased with conversion temperature. The maximum conversion ratio of Sr(OH)2 was 93.88% under the optimum condition, whose Sr/S ratio of sample could reach to 41.16. It illustrated that better isolation efficiency of celestite could be achieved in alkaline treatment. The results of SEM-EDS analyses demonstrated that the conversion reaction was a dissolution-precipitation process.

Study on the Low Energy Consumption Method for Light-Wight Devices in IoT Service Environment

Study on the Low Energy Consumption Method for Light-Wight Devices in IoT Service Environment