Browse
Records Added in 2020
Records added in 2020
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026
Filter by month: January | February | March | April | May | June | July | August | September | October | November | December
Showing records 714 to 738 of 1263. [First] Page: 1 26 27 28 29 30 31 32 33 34 Last
Estimation of Biomass Enzymatic Hydrolysis State in Stirred Tank Reactor through Moving Horizon Algorithms with Fixed and Dynamic Fuzzy Weights
Vitor B. Furlong, Luciano J. Corrêa, Fernando V. Lima, Roberto C. Giordano, Marcelo P. A. Ribeiro
June 10, 2020 (v1)
Keywords: artificial neural network, biomass enzymatic hydrolysis, fuzzy logic, local linear model tree, moving horizon estimation, process monitoring, soft sensing
Second generation ethanol faces challenges before profitable implementation. Biomass hydrolysis is one of the bottlenecks, especially when this process occurs at high solids loading and with enzymatic catalysts. Under this setting, kinetic modeling and reaction monitoring are hindered due to the conditions of the medium, while increasing the mixing power. An algorithm that addresses these challenges might improve the reactor performance. In this work, a soft sensor that is based on agitation power measurements that uses an Artificial Neural Network (ANN) as an internal model is proposed in order to predict free carbohydrates concentrations. The developed soft sensor is used in a Moving Horizon Estimator (MHE) algorithm to improve the prediction of state variables during biomass hydrolysis. The algorithm is developed and used for batch and fed-batch hydrolysis experimental runs. An alteration of the classical MHE is proposed for improving prediction, using a novel fuzzy rule to alter th... [more]
Temperature Distribution Estimation in a Dwight−Lloyd Sinter Machine Based on the Combustion Rate of Charcoal Quasi-Particles
Ziming Wang, Ko-ichiro Ohno, Shunsuke Nonaka, Takayuki Maeda, Kazuya Kunitomo
June 10, 2020 (v1)
Keywords: Biomass, charcoal combustion rate, coke combustion rate, iron ore sintering process, quasi-particle, temperature distribution
The coke combustion rate in an iron ore sintering process is one of the most important determining factors of quality and productivity. Biomass carbon material is considered to be a coke substitute with a lower CO2 emission in the sintering process. The purpose of this study was to investigate the combustion rate of a biomass carbon material and to use a sintering simulation model to calculate its temperature profile. The samples were prepared using alumina powder and woody biomass powder. To simplify the experimental conditions, alumina powder, which cannot be reduced, was prepared as a substitute of iron ore. Combustion experiments were carried out in the open at 1073 K~1523 K. The results show that the combustion rates of the biomass carbon material were higher than that of coke. The results were analyzed using an unreacted core model with one reaction interface. The kinetic analysis found that the kc of charcoal was higher than that of coke. It is believed that the larger surface a... [more]
In Memoriam of Professor Roger W.H. Sargent, the Founder of “Process Systems Engineering”
Rafiqul Gani, Ian Cameron
June 10, 2020 (v1)
Subject: Other
In September 2018, the global chemical engineering community lost a true pioneer in the field [...]
Forward Osmosis: A Critical Review
Mehrdad Mohammadifakhr, Joris de Grooth, Hendrik D. W. Roesink, Antoine J. B. Kemperman
June 10, 2020 (v1)
Keywords: concentration polarization, forward osmosis, membrane support, structural parameter
The use of forward osmosis (FO) for water purification purposes has gained extensive attention in recent years. In this review, we first discuss the advantages, challenges and various applications of FO, as well as the challenges in selecting the proper draw solution for FO, after which we focus on transport limitations in FO processes. Despite recent advances in membrane development for FO, there is still room for improvement of its selective layer and support. For many applications spiral wound membrane will not suffice. Furthermore, a defect-free selective layer is a prerequisite for FO membranes to ensure low solute passage, while a support with low internal concentration polarization is necessary for a high water flux. Due to challenges affiliated to interfacial polymerization (IP) on non-planar geometries, we discuss alternative approaches to IP to form the selective layer. We also explain that, when provided with a defect-free selective layer with good rejection, the membrane su... [more]
Antioxidant Activity and Sensory Improvement of Angelica dahurica cv. Yubaizhi Essential Oil on Sunflower Oil during High-temperature Storage
Dongying Wang, Yudong Meng, Chenxin Wang, Xuede Wang, Francesca Blasi
June 10, 2020 (v1)
Subject: Biosystems
Keywords: Angelica dahurica cv. Yubaizhi, antioxidant activity, sensory improvement, sunflower oil
The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at 65 °C, ADEO (800 ppm) was able to markedly inhibit the development of the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), thiobarbituric acid reactive substances (TBARS), total polar compounds (TPC), and the absorbance at 232 and 268 nm (p < 0.01 or p < 0.05) of sunflower oil and to prominently inhibit the transformation between unsaturated fatty acids (UFA) and saturated fatty acids (SFA). Interestingly, the synergistic effect of ADEO (400 ppm) and tert-butyl hydroquinone (TBHQ, 100 ppm) was demonstrated. Furthermore, the sensory attributes such as flavor, taste, and overall acceptability of oxidized sunflower oil added by ADEO at 200, 400, and 800 ppm were m... [more]
A Comparative Study of Virgin Coconut Oil, Coconut Oil and Palm Oil in Terms of Their Active Ingredients
Suryani Suryani, Sariani Sariani, Femi Earnestly, Marganof Marganof, Rahmawati Rahmawati, Sevindrajuta Sevindrajuta, Teuku Meurah Indra Mahlia, Ahmad Fudholi
June 10, 2020 (v1)
Subject: Biosystems
Keywords: bacteriocin, lactic acid bacteria (LAB), lauric acid, virgin coconut oil (VCO)
This research aims to study the unique factors of virgin coconut oil (VCO) compared with coconut oil (i.e., coconut oil processed through heating the coconut milk and palm oil sold on the market). Its novelty is that it (VCO) contains lactic acid bacteria and bacteriocin. Lauric acid content was analyzed by the Chromatographic Gas method. Isolation of lactic acid bacteria (LAB) was conducted by the dilution method using MRSA + 0.5% CaCO3 media. Iodium number, peroxide, and A were analyzed using a general method, and isolation bacteriocin by the deposition method using ammonium sulfate. In addition, macromolecular identification was conducted by 16S rRNA. VCO was distinguished by a higher content of lauric acid (C12:0) 41%−54.5% as compared with 0% coconut and 0, 1% palm oil, respectively. The VCO also contains LAB, namely Lactobacillus plantarum and Lactobacillus paracasei, and can inhibit the growth of pathogenic bacteria, such as Pseudomonas aeruginosa, Klebsiella, Staphylococcus aur... [more]
Evaluation of Calcium Oxide Nanoparticles from Industrial Waste on the Performance of Hardened Cement Pastes: Physicochemical Study
Youssef Abdelatif, Abdel-Aal M. Gaber, Abd El-Aziz S. Fouda, Tarek Alsoukarry
June 10, 2020 (v1)
Subject: Materials
Keywords: blended cement paste, bulk density, calcination, calcium oxide nanoparticles, compressive strength, mix design
Large amounts of carbonated mud waste (CMW) require disposal during sugar manufacturing after the carbonation process. The lightweight of CMW enables its utilization as a partial replacement for the cement to reduce costs and CO2 emissions. Here, various levels of CMW, namely, 0, 5, 10, 15, 20, and 25 wt.% were applied to produce composite cement samples with ordinary Portland cement (OPC) as a regular mix design series. Pure calcium oxide (CaO) nanoparticles were obtained after the calcination of CMW. The techniques of X-ray fluorescence spectrometers (XRF), Transmission electron microscope (TEM), Selected area diffraction (SAED), Scanning electron microscope (SEM), energy dixpersive X-ray (EDX), and dynamic light scattering (DLS) were used to characterize the obtained CaO nanoparticles. According to the compressive strength and bulk density results, 15 wt.% CMW was optimal for the mix design. The specific surface area increased from 27.8 to 134.8 m2/g when the CMW was calcined to 600... [more]
Mathematical Model for the Removal of Essential Oil Constituents during Steam Distillation Extraction
Sharad Maharaj, David McGaw
June 10, 2020 (v1)
Keywords: convective mass transfer, element-by-element, essential oil, extraction curve, Ocimum basilicum, steam distillation
Steam distillation is the conventional means by which oils are extracted in the flavour and fragrance industry. A mathematical model for the steam distillation extraction (SDE) of air-dried Ocimum basilicum (basil) leaves has been developed and tested using a small-scale pilot plant. The model predicts the removal of oil components from the plant matrix and subsequent transfer to the steam. It also accounts for the diffusional transfer of components within the leaf and the simultaneous convective transfer into the vapour phase while also respecting the individual components’ volatilities. It has been applied vertically on an element-by-element basis through the bed for a mixture of major and minor components. The proposed SDE model appears to be a good match between predicted values and the experimental data. The model predicts a faster initial extraction rate for components such as α-pinene and α-terpinene, possibly due to preferential extraction of light, volatile components present... [more]
Experiments and 3D Molecular Model Construction of Lignite under Different Modification Treatment
Jihui Liu, Shuang Qiu, Zhijun He, Yaowei Yu
June 10, 2020 (v1)
Keywords: 3D molecular model, Lignite, microwave and ultrasound modification, structural characterization, structural simulation
In this paper, Huolinhe lignite was selected as the lignite experimental sample, using microwave modification and ultrasonic modification separately as improvement methods. The three-dimensional molecular models of HLH before and after modification were established base on the parameters obtained by 13C NMR, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman), and Fourier transform infrared (FTIR). After the microwave treatment, the methylene carbon in the HLH coal sample structure mostly exists in the form of long straight chains, and after microwave and ultrasonic treatment, the -OH content of oxygen atoms in the coal sample increases, and form the CO- and the COO-. The proportion is decreasing. The models were adjusted and tested by the covalent bond concentration method and carbon chemical shift spectra calculation using Chemdraw software. A new method is proposed to study the structure and physicochemical properties of lignite modification from the molecular point o... [more]
A Simple Approach for Determining the Maximum Sorption Capacity of Chlorpropham from Aqueous Solution onto Granular Activated Charcoal
Bandar R. M. Alsehli
June 10, 2020 (v1)
Subject: Materials
Keywords: chlorpropham, isotherm models, UV/VIS
UV-Vis spectrophotometer was used to determine chlorpropham (CIPC) concentration in aqueous solution. The method was validated in term of linearity, precision and limit of detection and limit of quantitation. The correlation coefficient of standards calibration curve of (1.0−10.0 µg/mL CIPC) was R2 = 1 with a precision (RSD%, n=10) ranged from (0.87−0.53%). The limit of detection (LOD) and limit of quantitation (LOQ) based on the regression statistics of the calibration curve data of (1.0−10.0 µg/mL CIPC) were 0.04 µg/mL and 0.11 µg/mL respectively. The activated carbon adsorbent was found to be effective for the removal approximately 80% of CIPC from aqueous solution. Several isotherm models (Langmuir, Freundlich, Tempkin and Dubinin−Radushkevich) were evaluated. The maximum monolayer sorption capacity (Qm) from the Langmuir isotherm model was determined to be (44316.92 µg/g). The separation factor (RL) is 0.11 which indicates a favorable equilibrium sorption with the R2 value of 0.99... [more]
Fast Screening Methods for the Analysis of Topical Drug Products
Margarida Miranda, Catarina Cardoso, Carla Vitorino
June 10, 2020 (v1)
Keywords: RP-HPLC, semi-solid dosage forms, topical products, validation
Considering the recent regulatory requirements, the overall importance of in vitro release testing (IVRT) methods regarding topical product development is undeniable, especially when addressing particulate systems. For each IVRT study, several hundreds of samples are generated. Therefore, developing rapid reversed-phase high-performance liquid chromatography (RP-HPLC) methods, able to provide a real-time drug analysis of IVRT samples, is a priority. In this study, eight topical complex drug products exhibiting distinct physicochemical profiles were considered. RP-HPLC methods were developed and fully validated. Chromatographic separations were achieved on a XBridgeTM C18 (5 µm particle size, 150 mm × 2.1 mm), or alternatively on a LiChrospher® 100 RP-18 (5 µm particle size, 125 mm × 4.6 mm) at 30 °C, under isocratic conditions using UV detection at specific wavelengths. According to the physicochemical characteristics of each drug, different mobile phases were selected. Irrespective of... [more]
Treatment of Secondary Dust Produced in Rotary Hearth Furnace through Alkali Leaching and Evaporation−Crystallization Processes
Shuang Liang, Xiaoping Liang, Qian Tang
June 3, 2020 (v1)
Subject: Other
Keywords: alkali leaching, potassium, rotary hearth furnace, secondary dust, zinc
This paper presents the results of an experimental study on the extraction of KCl and the improvement of the zinc grade of secondary dust obtained from rotary-hearth-furnace secondary dust (RHF secondary dust) using alkali leaching (Na2CO3 solution) and evaporation−crystallization processes. The effects of the liquid−solid ratio and Na2CO3 content on the element leaching ratio in the alkali leaching process, as well as the effects of the volume−evaporation ratio and cooling temperature on KCl extraction in the evaporation−crystallization process, were investigated. The results showed that the optimum liquid−solid ratio was 6:1, and the optimum quantity of Na2CO3 was 1.5 times the basic quantity. The recovery ratio of zinc reached 95.23%, and the leaching ratio of K reached 79.01%. The experimental results of the evaporation−crystallization process demonstrated that the evaporation temperature was 80 °C, the volume evaporation ratio was 50%, the cooling temperature was 25 °C, and the ma... [more]
Sperm Proteomics Analysis of Diabetic Induced Male Rats as Influenced by Ficus carica Leaf Extract
Umarqayum Abu Bakar, Puvaratnesh Subramaniam, Nurul Ain Kamar Bashah, Amira Kamalrudin, Khaidatul Akmar Kamaruzaman, Malina Jasamai, Wan Mohd Aizat, M. Shahinuzzaman, Mahanem Mat Noor
June 3, 2020 (v1)
Subject: Biosystems
Keywords: diabetes mellitus, Ficus carica, proteomics, sperm quality
Diabetes mellitus is shown to bring negative effects on male reproductive health due to long-term effects of insulin deficiency or resistance and increased oxidative stress. Ficus carica (FC), an herbal plant, known to have high antioxidant activity and antidiabetic properties, has been used traditionally to treat diabetes. The objective of this study is to determine the potential of the FC leaf extract in improving sperm quality of streptozotocin (STZ) induced diabetic male rats from proteomics perspective. A total of 20 male rats were divided into four groups; normal (nondiabetic rats), negative control (diabetic rats without treatment), positive control (diabetic rats treated with 300 mg/kg metformin), and FC group (diabetic rats treated with 400 mg/kg FC extract). The treatments were given via oral gavage for 21 consecutive days. The fasting blood glucose (FBG) level of FC treated group demonstrated a significant (p < 0.05) decrease compared to negative group after 21 days of tr... [more]
Improvement of Productivity through the Reduction of Unexpected Equipment Faults in Die Attach Equipment
You-Jin Park, Sun Hur
June 3, 2020 (v1)
Keywords: back grinding process, die attach process, loss, overall equipment effectiveness (OEE), productivity analysis system, unexpected equipment fault, unit per equipment hour (UPEH), wafer sawing process
As one of the semiconductor back-end processes, die attach process is the process that attaches an individual non-defective die (or chip) produced from the semiconductor front-end production to the lead frame on a strip. With most other processes of semiconductor manufacturing, it is very important to improve productivity by lessening the occurrence of defective products generally represented as losses, and then find the fault causes which lower productivity of the die attach process. Thus, as the case study to analyze quantitatively the faults of the die attach process equipment, in this research, we developed analysis systems including statistical analysis functions to improve the productivity of die attach process. This research shows that the developed system can find the causes of equipment faults in die attach process equipment and help improve the productivity of the die attach process by controlling the critical parameters which cause unexpected equipment faults and losses.
Study on the Formation of Complex Chemical Waveforms by Different Computational Methods
Jiali Ai, Chi Zhai, Wei Sun
June 3, 2020 (v1)
Keywords: Belousov–Zhabotinsky reaction, cellular automata, finite difference, partial differential equations
Chemical wave is a special phenomenon that presents periodic patterns in space-time domain, and the Belousov−Zhabotinsky (B-Z) reaction is the first well-known reaction-diffusion system that exhibits organized patterns out of a homogeneous environment. In this paper, the B-Z reaction kinetics is described by the Oregonator model, and formation and evolution of chemical waves are simulated based on this model. Two different simulation methods, partial differential equations (PDEs) and cellular automata (CA) are implemented to simulate the formation of chemical waveform patterns, i.e., target wave and spiral wave on a two-dimensional plane. For the PDEs method, reaction caused changes of molecules at different location are considered, as well as diffusion driven by local concentration difference. Specifically, a PDE model of the B-Z reaction is first established based on the B-Z reaction kinetics and mass transfer theory, and it is solved by a nine-point finite difference (FD) method to... [more]
Spatial Life Cycle Analysis of Soybean-Based Biodiesel Production in Indiana, USA Using Process Modeling
Venkata Sai Gargeya Vunnava, Shweta Singh
June 3, 2020 (v1)
Keywords: biodiesel, Indiana, life cycle assessment, soybean, spatial
Life Cycle Analysis (LCA) has long been utilized for decision making about the sustainability of products. LCA provides information about the total emissions generated for a given functional unit of a product, which is utilized by industries or consumers for comparing two products with regards to environmental performance. However, many existing LCAs utilize data that is representative of an average system with regards to life cycle stage, thus providing an aggregate picture. It has been shown that regional variation may lead to large variation in the environmental impacts of a product, specifically dealing with energy consumption, related emissions and resource consumptions. Hence, improving the reliability of LCA results for decision making with regards to environmental performance needs regional models to be incorporated for building a life cycle inventory that is representative of the origin of products from a certain region. In this work, we present the integration of regionalized... [more]
Fault Detection and Identification of Blast Furnace Ironmaking Process Using the Gated Recurrent Unit Network
Hang Ouyang, Jiusun Zeng, Yifan Li, Shihua Luo
June 3, 2020 (v1)
Keywords: fault detection and identification, gated recurrent unit, support vector data description, time sequence prediction
It is of critical importance to keep a steady operation in the blast furnace to facilitate the production of high quality hot metal. In order to monitor the state of blast furnace, this article proposes a fault detection and identification method based on the multidimensional Gated Recurrent Unit (GRU) network, which is a kind of recurrent neural network and is highly effective in handling process dynamics. Comparing to conventional recurrent neural networks, GRU has a simpler structure and involves fewer parameters. In fault detection, a moving window approach is applied and a GRU model is constructed for each process variable to generate a series of residuals, which is further monitored using the support vector data description (SVDD) method. Once a fault is detected, fault identification is performed using the contribution analysis. Application to a real blast furnace fault shows that the proposed method is effective.
Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals
Feng Qiu, Dameng Liu, Yidong Cai, Ning Liu, Yongkai Qiu
June 3, 2020 (v1)
Subject: Materials
Keywords: adsorption potential, coalbed methane, controlling factors, Langmuir adsorption curve, pore structure
Water content, metamorphism (coal rank) particle size, and especially pore structure, strongly influence the adsorption capacity of coal to methane. To understand the mechanism of methane adsorption in different rank coals, and its controlling factors, isothermal adsorption experiments with different coal ranks, moisture contents and particle sizes at the temperature of 303.15 K were conducted. In addition, the pore structures of coals were investigated through N2 adsorption/desorption experiments at the low-temperature of 77 K for selected coals from the Junggar Basin of NW China, Qinshui Basin and Ordos Basin of north China. Moreover, the adsorption potential of methane on the surface of the coal matrix was calculated, the controlling factors of which were discussed. The obtained methane isothermal adsorption result shows that the Langmuir volume (VL) of coal is independent of the particle size, and decreases with the increase of moisture content, which decreases first and then incre... [more]
Wholemeal Spelt Bread Enriched with Green Spelt as a Source of Valuable Nutrients
Piotr Kraska, Sylwia Andruszczak, Urszula Gawlik-Dziki, Dariusz Dziki, Ewa Kwiecińska-Poppe
June 3, 2020 (v1)
Subject: Biosystems
Keywords: bread, chemical composition, green grain, spelt wheat
The aim of this study was to evaluate the nutritional value of wholemeal bread prepared from the flour of spelt wheat (Triticum aestivum ssp. spelta) that was enriched by the addition of freeze-dried spelt grain (at proportions of 4%, 8%, and 12%, respectively, in relation to the flour weight). The spelt grain used in the study was harvested at the milk dough stage (the so-called green grain). Green spelt grain was characterized by a significantly higher content of minerals namely P, Mg, Ca and Zn compared to ripe spelt grain. Additionally, it contained significantly higher amounts of amino acids (Asp, Thr, Ser, Gly, Ala, Cys, Val, Met, Ile, Leu, Phe, Lys), lipids, as well as monounsaturated fatty acids (MUFA), and omega-3 and omega-9 acids. However, it had a lower content of palmitic, stearic, and linoleic acids, polyunsaturated fatty acids (PUFA), and omega-6 acids. The results showed that the nutritional value of bread was improved by the green spelt grain, however the ω6/ω3 ratio i... [more]
Antibacterial, Antibiofilm and Anticancer Activity of Biologically Synthesized Silver Nanoparticles Using Seed Extract of Nigella sativa
Ahmad Almatroudi, Habeeb Khadri, Mohd Azam, Arshad Husain Rahmani, Fahd Khaleefah Al Khaleefah, Riazunnisa Khateef, Mohammad Azam Ansari, Khaled S. Allemailem
June 3, 2020 (v1)
Subject: Biosystems
Keywords: anti-biofilm, anti-cancer, HCC-712 cell lines, Nigella sativa, silver nanoparticle
Silver nanoparticle (AgNP) based approaches using plant materials have been accepted as biomedical applications. The current study aimed to test the antibacterial, antibiofilm, and anticancer activity of silver nanoparticles synthesized by seed extract of Nigella sativa (Ns) as stabilizing and reducing agents. Characterization was done through UV−visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electronic microscopy (SEM), and transmission electronic microscopy (TEM) analyses. UV-Vis spectroscopy showed a specific silver plasmon peak at 400 nm and a quick color change was observed in the bio-reaction medium. Electron microscopic images of Ns-AgNPs identified as spherical in shape with varied size ranged between 8 and 80 nm and zeta potential analysis evidenced the particles stability and polydisperity. Antibiofilm activity of Ns-AgNPs was evident as at 12.5 µg/mL Ns-AgNps restricted the biofilm formation by 88.42% for Enterococcus... [more]
Low-Molecular-Weight Phenols Recovery by Eco-Friendly Extraction from Quercus Spp. Wastes: An Analytical and Biomass-Sustainability Evaluation
Federica Ianni, Enrico Segoloni, Francesca Blasi, Francesco Di Maria
June 3, 2020 (v1)
Subject: Materials
Keywords: circular economy, lignin, mild extraction/hydrolysis protocols, phenolic compounds recovery, wood waste
In this work, chemical−physical protocols aimed at the implementation of eco-friendly and biomass-sustainable recovery processes of useful compounds from forestry and/or wood industry wastes were evaluated. Four species of interest in industrial and environmental fields (Quercus cerris, Quercus ilex, and Robinia pseudoacacia from Central Italy, Quercus petraea from France) were submitted to neutral extraction and analyzed by gaschromatography, with mass spectrometry identification of low-molecular-weight phenols. Moreover, Quercus petraea heartwood samples were submitted to three extraction/hydrolysis protocols in an alkaline environment, and the byproducts from the lignin degradation were identified and evaluated. The recovery of bioactive phenols from forestry wastes by applying eco-friendly extractive protocols may reveal a precious strategy for rethinking the management of such wastes, in line with the fundamentals of “circular economy”.
Special Issue on “Computational Methods for Polymers”
Masoud Soroush
June 3, 2020 (v1)
Polymers play a key role in our daily lives [...]
Simulation Study and Industrial Application of Enhanced Arsenic Removal by Regulating the Proportion of Concentrates in the SKS Copper Smelting Process
Qinmeng Wang, Qiongqiong Wang, Qinghua Tian, Xueyi Guo
June 3, 2020 (v1)
Subject: Other
Keywords: arsenic removal, copper smelting, oxygen bottom blown, Shuikoushan process, SKS
Arsenic removal is a crucial issue in all copper smelters. Based on the Fangyuan 1# smelter, the effects of major elements (Cu, Fe and S) in sulfide concentrates on arsenic removal in the SKS copper smelting process were studied in this paper. The results show that Cu, Fe and S in concentrates have a significant influence on the oxygen/sulfur potential of smelting systems, and also affect the efficiency of arsenic removal. By regulating the proportion of the major elements in sulfide concentrates, the concentrate composition was changed from its original proportions (Cu 24.4%, Fe 26.8%, S 28.7%, and other 20%) to optimized proportions (Cu 19%, Fe 32%, S 29%, and other 20%). The distribution of arsenic among three phases in the original production process (gas 82.01%, slag 12.08%, matte 5.91%) was improved to obtain an optimal result (gas 94.37%, slag 3.45%, matte 2.18%). More arsenic was removed into the gas phase, and the mass fraction of arsenic in matte was reduced from 0.07% to 0.0... [more]
A Review of Landfill Leachate Treatment by Microalgae: Current Status and Future Directions
Tabish Nawaz, Ashiqur Rahman, Shanglei Pan, Kyleigh Dixon, Burgandy Petri, Thinesh Selvaratnam
June 3, 2020 (v1)
Subject: Biosystems
Keywords: landfill leachate, leachate remediation, leachate treatment, microalgae, phycoremediation, resource recovery, resource recovery, Sustainability
Solid waste generation has been projected to increase worldwide. Presently, the most applied methodology to dispose of solid waste is landfilling. However, these landfill sites, over time release a significant quantity of leachate, which can pose serious environmental issues, including contamination of water resources. There exist many physicochemical and biological landfill leachate treatment schemes with varying degrees of success. With an increasing focus on sustainability, there has been a demand for developing eco-friendly, green treatment schemes for landfill leachates with viable resource recovery and minimum environmental footprints. Microalgae-based techniques can be a potential candidate for such a treatment scenario. In this article, research on microalgae-based landfill leachate treatments reported in the last 15 years have been summarized and critically reviewed. The scale-up aspect of microalgae technology has been discussed, and the related critical factors have been elu... [more]
Evaluating Pre- and Post-Coagulation Configuration of Dissolved Air Flotation Using Response Surface Methodology
Emmanuel Kweinor Tetteh, Sudesh Rathilal
June 3, 2020 (v1)
Keywords: coagulants, Coagulation, dissolved air flotation, oil refinery wastewater, response surface methodology
The effects of coagulation-dissolved air flotation (DAF) process configuration was studied on oil refinery wastewater. The configuration was done in two ways: acid-coagulation-DAF (pre-treatment) and acid-DAF-coagulation (post-treatment). Two different cationic and polymeric organic coagulants were employed in this study to compare their treatability performance with the two aforementioned configurations. All the coagulants applied before the DAF were found to be effective, with over 85% more contaminant removal efficiency than their post-treatment. Alum, being the most cost-effective coagulant, was then employed with response surface methodology (RSM) to obtain the optimum conditions. These include a coagulant dosage of 100 mg/L, air saturator pressure of 375 kPa and air−water ratio of 10% vol/vol corresponding to a desirability of 92% for the removal of oily pollutants from a local South Africa oil refinery’s wastewater. With the response quadratic models that were developed, the opt... [more]
Showing records 714 to 738 of 1263. [First] Page: 1 26 27 28 29 30 31 32 33 34 Last
(0.03 seconds)
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026
Filter by month: January | February | March | April | May | June | July | August | September | October | November | December

[0.03 s]