scholarly journals Effect of heating temperature and time on the phosphate adsorption capacity of thermally modified copper tailings

2018 ◽  
Vol 77 (11) ◽  
pp. 2668-2676 ◽  
Author(s):  
Runjuan Zhou ◽  
Youbao Wang ◽  
Ming Zhang ◽  
Jing Li ◽  
Yanan Gui ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Heating Temperature ◽  
Heating Time ◽  
Current Data ◽  
Phosphate Adsorption ◽  
Adsorption Ability ◽  
Copper Tailings ◽  
Adsorption Capacities ◽  
Different Temperatures ◽  
Best Fit

Abstract In the present study, copper tailings were treated at different temperatures (50–650 °C) and for various times (0.5–6 hours) and their phosphate adsorption capacity was investigated. The results showed that heating temperature significantly affected adsorption capacity. The highest capacity was observed in treatments at 310–350 °C. Heating time did not influence phosphate adsorption ability of copper tailings. Scanning electron microscopy, Barrett–Joyner–Halenda (BJH), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize untreated copper tailings (raw CT) and copper tailings heated at 340 °C (CT340). The results showed that CT340 had a rougher surface, more and smaller pores, a larger surface area and higher FTIR transmittance than raw CT. These changes in texture might explain the increased phosphate adsorption of thermally modified copper tailings. Mathematical modeling showed that the Langmuir nonlinear model was the best fit to the current data. The maximum adsorption capacities of raw CT and CT340 were predicted as 2.08 mg/g and 14.25 mg/g at 298 K, pH 6.0, respectively.

scholarly journals Dewatered alum sludge: a potential adsorbent for phosphorus removal

2006 ◽  
Vol 54 (5) ◽  
pp. 207-213 ◽  
Author(s):  
Y. Yang ◽  
D. Tomlinson ◽  
S. Kennedy ◽  
Y.Q . Zhao
Keyword(s):  
Water Treatment ◽  
Adsorption Capacity ◽  
Phosphorus Removal ◽  
Adsorption Process ◽  
Study Groups ◽  
Phosphorus Adsorption ◽  
Langmuir Adsorption ◽  
Adsorption Capacities ◽  
Alum Sludge ◽  
Best Fit

Alum sludge refers to the by-product from the processing of drinking water in water treatment works. In this study, groups of batch experiments were designed to identify the characteristics of dewatered alum sludge for phosphorus adsorption. Air-dried alum sludge (moisture content 10.2%), which was collected from a water treatment works in Dublin, was subjected to artificial P-rich wastewater adsorption tests using KH2PO4 as a model P source. Adsorption behaviours were investigated as a function of amount and particle size of alum sludge, pH of solution and adsorption time. The results have shown that pH plays a major role not only in the adsorption process but also in the adsorption capacity. With regard to adsorption capacity, this study reveals the Langmuir adsorption isotherm being the best fit with experimental data (R2=0.98–0.99). The maximum adsorption capacities range from 0.7 to 3.5 mg-P/g when the pH of the synthetic P solution was varied from 9.0 to 4.3, accordingly. The outcome of this study indicated that alum sludge is suitable for use as an adsorbent for removal of phosphate from wastewater.

scholarly journals Effect of Drying Processes on Stability of Anthocyanin Extracts from Saffron Petal

2014 ◽  
Vol 2 ◽  
pp. 13-18 ◽  
Author(s):  
Somayeh Heydari ◽  
Roya Rezaei ◽  
Gholam Hossein Haghayegh
Keyword(s):  
Room Temperature ◽  
Heating Temperature ◽  
Heating Time ◽  
Crocus Sativus ◽  
The Sun ◽  
Processing Treatment ◽  
Different Temperatures ◽  
The Stability ◽  
Synthetic Pigments ◽  
Good Substitute

Saffron (Crocus sativus) has cyanic color flowers with major colorant of anthocyanin. Attractive color and functional properties of anthocyanins make them a good substitute for synthetic pigments in the food industry. These natural soluble water colorants are rather unstable and influenced by final processing treatment. The drying process is critical to the stability of saffron petals anthocyanins. Four different dehydration methods were evaluated: traditional method (at room temperature and under the sun); dehydration with electrical oven at different temperatures; and dehydration with microwave at different powers. The results showed that the highest amount of anthocyanin was obtained when saffron petals treated by traditional methods (at room temperature and under the sun). According to the results, the stability of saffron petals anthocyanins gradually accessed with increase of the heating temperature and decrement of heating time until 100 °C. However, heated at 120 and 140 °C, the anthocyanins could break down, and their residual amounts declined within 20 min and 10 min, respectively. The results suggested that saffron petals anthocyanins tended to degrade at high temperatures (>100 °C). Between these methods, drying at room temperature and drying with microwave at 900 W obtained the highest and the lowest results respectively.

scholarly journals Effects of Temperature on Bending Properties of Three-Dimensional and Five-Directional Braided Composite

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3977
Author(s):  
Li ◽  
Jia ◽  
Pei ◽  
Wan ◽  
Li ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Room Temperature ◽  
Bending Strength ◽  
Heating Temperature ◽  
Three Dimensional ◽  
Heating Time ◽  
Resin Composites ◽  
Bending Properties ◽  
Different Temperatures ◽  
Epoxy Resin Composites

The bending properties of three-dimensional (3Dim) and five-directional (5Dir) braided/epoxy resin composites at room temperature, 90 °C, 110 °C, and 150 °C and heating for 0.25 h, 10 h, and 30 h, respectively, were studied. The effect of different temperatures and heating times on the bending property of these composites was discussed. The results showed that the bending strength of these composites at 90 °C, 110 °C, and 150 °C and heating time of 0.25 h is 33.86%, 46.27%, and 83.94% lower, respectively, than that at room temperature. In addition, 3Dim–5Dir braided composites exhibit different damage modes at different temperatures, revealing different failure mechanisms. Heating temperature has greater influence on the bending properties of these composites than heating time. The results provided a basis for the application of resin-based 3Dim–5Dir braided/epoxy resin composites at different temperatures.

scholarly journals Optimization of biochar preparation from the stem of Eichhornia crassipes using response surface methodology on adsorption of Cd2+

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Runjuan Zhou ◽  
Ming Zhang ◽  
Jinhong Zhou ◽  
Jinpeng Wang
Keyword(s):  
Response Surface Methodology ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Heating Rate ◽  
Eichhornia Crassipes ◽  
Heating Temperature ◽  
Removal Rate ◽  
Heating Time ◽  
Optimal Conditions ◽  
Preparation Conditions

AbstractIn this study, preparation of Eichhornia crassipes stem biochar (ECSBC) was optimized and applied for the removal of Cd2+ from aqueous solution. To obtain the best adsorption capacity of ECSBC, the response surface methodology (RSM) was used to optimize the preparation conditions of ECSBC (OECSBC). The interactions among heating time (X1), heating temperature (X2) and heating rate (X3) were designed by Box-Behnken Design (BBD) experiments. The software gave seventeen runs experiment within the optimal conditions towards two response variables (removal rate and adsorption capacity for Cd2+). The results showed that the mathematical model could fit the experimental data very well and the significance of the influence factors followed the order as heating temperature (X2) > heating rate (X3) > heating time (X1), and the influence of interaction term is: X1 and X2 (heating time and heating temperature) > X2 and X3 (heating temperature and heating rate) > X1 and X3 (heating time and heating rate). Based on the analysis of variance and the method of numerical expected function, the optimal conditions were heating time of 2.42 h, heating temperature of 393 °C, and heating rate of 15.56 °C/min. Under the optimum conditions, the predicted the maximum removal rate and adsorption capacity were 85.2724% and 21.168 mg/g, respectively, and the experimental value of removal rate and adsorption capacity for Cd2+ were 80.70% and 20.175 mg/g, respectively, the deviation from the predicted value were 5.36% and 4.69%. The results confirmed that the RSM can optimize the preparation conditions of ECSBC, and the adsorption capacity of OECSB was improved.

The use of insoluble matter of Moroccan oil shale for removal of dyes from aqueous solution

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methylene Blue ◽  
Oil Shale ◽  
Heating Temperature ◽  
Blue Dye ◽  
Adsorption Capacities ◽  
Experimental Parameters ◽  
Initial Ph ◽  
New Material ◽  
Activating Agent ◽  
Moderate Cost

The study aims to use an adsorbent natural based of Moroccan oil shale of Timahdit area (Y layer) in a physical-chemical adsorption process for treating industrial discharges colorful. The used adsorbent is the insoluble party of the sub-critical extraction of decarbonized oil shale of Timahdit. The tests performed on the methylene blue (MB), showed a strong elimination in the first 10 minutes. The influences of various experimental parameters were studied: mass ratio of adsorbent, time and temperature of thermal treatment, contact time, pH of MB and heating temperature of solution on the parameters of material were studied. The experimental results have shown that the adsorption of methylene blue dye by the adsorbent is more than 90% at initial pH a range 6-7 at room temperature for 30 minutes. The process is simple and the adsorbent produced is a new material with interesting adsorption capacities of moderate cost which does not require an activating agent and can be used as industrial adsorbent for the decontamination of effluents containing organic pollutants.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

Competitive Biosorption of Pb(II) and Cu(II) by Functionalised Micropogonias undulates Scales

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Ibrahim O. Tijani ◽  
Oluwaseun J. Ajala ◽  
Fisayo O. Ayandele ◽  
Omodele A. Eletta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Low Cost ◽  
Fish Scales ◽  
Wet Impregnation ◽  
Monolayer Adsorption ◽  
Competitive Biosorption ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Best Fit

Background: Modified bio-based adsorbents from plant sources can be used for pollution remediation by adsorption due to their low cost and availability in large quantities. Objective: In this study, the competitive biosorption of Pb(II) and Cu(II) by Micropogonias undulates functionalised fish scales (FFS) was conducted. The functionalisation was done by wet impregnation with Fe2+. Method: The biosorbent was characterised by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS) and Branueur–Emmett–Teller (BET) analyses. Results: The major constituents in the FFS were calcium and phosphorus from the collagen and apatite on the scales. Optimum removal efficiency for both metals was >99% at 10 g/l dosage. It was observed that the Langmuir isotherm model and the pseudo second order kinetics model were the best fit for the experimental data. The monolayer adsorption capacity of FFS for Pb(II) and Cu(II) was observed to be 96.15 mg/g and 100 mg/g respectively. Conclusion: The study revealed that the competitive biosorption of heavy metals can be achieved (at a good adsorption capacity) using functionalised Micropogonias undulates fish scales.

Development and Characterization of Amine-Clay Hybrid Adsorbents for CO2 Capture

2016 ◽  
Vol 1133 ◽  
pp. 547-551 ◽  
Author(s):  
Ali E.I. Elkhalifah ◽  
Mohammad Azmi Bustam ◽  
Azmi Mohd Shariff ◽  
Sami Ullah ◽  
Nadia Riaz ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Surface Properties ◽  
Molar Mass ◽  
Adsorption Ability ◽  
Stepwise Increase ◽  
Inverse Effect ◽  
Bet Method ◽  
Sodium Form

The present work aims at a better understanding of the influences of the intercalated mono-, di- and triethanolamines on the characteristics and CO2 adsorption ability of sodium form of bentonite (Na-bentonite). The results revealed that the molar mass of intercalated amines significantly influenced the structural and surface properties as well as the CO2 adsorption capacity of Na-bentonite. In this respect, a stepwise increase in the d-spacing of Na-bentonite with the molar mass of amine was recorded by XRD technique. However, an inverse effect of the molar mass of amine on the surface area was confirmed by BET method. CO2 adsorption experiments on amine-bentonite hybrid adsorbents showed that the CO2 adsorption capacity inversly related to the molar mass of amine at 25 ͦC and 101 kPa. Accordingly, Na-bentonite modified by monoethanolammonium cations adsorbed as high as 0.475 mmol CO2/g compared to 0.148 and 0.087 mmol CO2/g for that one treated with di- and triethanolammonium cations, respectively.

scholarly journals Study on Ultra-High Temperature Contact Solution Treatment of Al–Zn–Mg–Cu Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 842
Author(s):  
Wenming Jin ◽  
Jianhao Yu ◽  
Zhiqiang Zhang ◽  
Hongjie Jia ◽  
Mingwen Ren
Keyword(s):  
Heating Temperature ◽  
Solution Treatment ◽  
Strengthening Mechanism ◽  
Heating Time ◽  
Solution Time ◽  
Solution Temperature ◽  
Second Phase ◽  
Total Strength ◽  
Cu Alloys ◽  
Short Heating Time

Contact solution treatment (CST) of Al–Zn–Mg–Cu alloys can shorten solution time to within 40 s in comparison with 1800 s with traditional solution treatment using a heating furnace. Heating temperature is the key factor in solution treatment. Considering the short heating time of CST, the ultra-high solution temperature over 500 °C of Al–Zn–Mg–Cu alloys was studied in this work. The effects of solution temperatures on the microstructures and the mechanical properties were investigated. The evolution of the second phases was explored and the strengthening mechanisms were also quantitatively evaluated. The results showed that solution time could be reduced to 10 s with the solution temperature of 535 °C due to the increasing dissolution rate of the second phase and the tensile strength of the aged specimen could reach 545 MPa. Precipitation strengthening was the main strengthening mechanism, accounting for 75.4% of the total strength. Over-burning of grain boundaries occurred when the solution temperature increased to 555 °C, leading to the deterioration of the strength.

Numerical Simulation and Process Optimization of Automotive Friction Materials in Warm Pressing Forming

2013 ◽  
Vol 788 ◽  
pp. 57-60
Author(s):  
Chun Cao ◽  
Chun Dong Zhu ◽  
Chen Fu
Keyword(s):  
Process Optimization ◽  
Heating Temperature ◽  
Maximum Energy ◽  
Heating Time ◽  
Product Performance ◽  
Forming Process ◽  
Friction Materials ◽  
Forming Technology ◽  
The Relationship ◽  
Temperature Heating

Warm pressing forming technology has been gradually applied to the forming of automotive friction materials. How to ensure product performance to achieve the target at the same time achieve the maximum energy saving is the research focus of this study. In this paper, by using finite element method, the field of automotive friction materials in warm pressing forming was analyzed, reveals the relationship between the temperature field and the heating temperature/heating time. Furthermore, the energy consumption was analyzed and compared it with hot pressing forming process. The results will have significant guiding to the process optimization in warm pressing forming.

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