Effect Of Water Washing Research Articles

Influence of water-washing pretreatment on ash fusibility of biomass

As the carbon-neutral fuel, biomass has shown great potential to partially substitute fossil fuels. However, the application of biomass combustion in boiler was restricted by the biomass compositions. To improve the ash fusibility performance of biomass, water washing pretreatment was proposed. The influences of water washing on ash composition, ash fusion temperatures (AFTs), and ash dynamic behavior during fusion process were investigated through experimental methods and thermodynamic equilibrium calculations. The results show that water washing could increase the initial deformation temperature of biomass ash by removing alkali metals. The K2O removal efficiency is within 69%–90% for six biomass fuels. Traditional fouling and slagging indexes could be employed to predict the ash fusibility of corn stalk, wheat straw, rice straw and rice hull. But these indexes are not suitable for that of candlenut wood or cotton stalk. Furthermore, a convenient and effective method to study the dynamic behavior of biomass ash during fusion process is proposed. It could reveal the interaction of solid and liquid phases in ash. The effect of water washing on AFTs could be explained by thermodynamic equilibrium calculations. Finally, 30 °C is recommended as the water washing temperature to adjust the ash fusibility of biomass.

Destabilization of the surface structure of Ni-rich layered materials by water-washing process

Washing Ni-rich layered materials with water is a simple and effective way to reduce gas evolution by eliminating the gas generation factors. However, the water-washing process itself degrades the electrochemical performances; hence additional treatments such as heating and coating are undertaken. Thus, most studies for the post-process mainly focus on the relationship between additional treatments and electrochemical performances, not paying much attention to the water-washing effect. Here, we focused on the effect of water-washing on the Ni-rich layered materials by studying bare and water-washed LiNi0.88Co0.054Mn0.066O2(NCM) cathodes. The results of synchrotron-based X-ray analysis indicate that the crystal and electronic structures are the same in the bulk aspect after the water-washing process, but differences occur in the surface environment. The amount of Li2CO3 decreases while NiO-like rock-salt phase increases on the surface of the water-washed NCM, and it deteriorates the rate performances by elevating the surface resistances. Furthermore, the surface layer reconstruction of water-washed NCM, which has lower capacity retention during 200 cycles, is much more severe than the bare NCM; this indicates that the water-washing process makes the surface of Ni-rich layered materials more vulnerable to the side reaction, facilitating the formation of NiO-like rock-salt phase by the reconstruction.

Catalytic pyrolysis: New approach for destruction of POPs in MWIs fly ash

Combined water washing with catalysis was applied in pyrolysis process to enhance the destruction efficiencies of PCDD/Fs and dl-PCBs in MWI fly ash. The results indicate that water or carbonated water washing effectively reduces chloride content in fly ash but it contributes minor enhancement of PCDD/Fs and dl-PCBs destructions achieved with pyrolysis process. Being pyrolyzed at temperature of 350 °C for 1 h, the removal efficiencies of 96.7%, 98.5% and 96.2% for PCDD/Fs, and 79.3%, 92.3% and 87.3% for dl-PCBs are achieved for unwashed fly ash, water washed fly ash and carbonated water washed fly ash, respectively. Nonetheless, TEQ concentrations of PCDD/Fs and dl-PCBs in pyrolyzed fly ash remain higher than the European end-of-waste criteria (20 pg WHO-TEQ/g). As palladium was added to the system as catalyst, the decay rates of PCDDs, PCDFs and dl-PCBS in fly ash increase significantly even with a much shorter pyrolysis time (15 min). Increases of PCDD/Fs and dl-PCBs destruction efficiencies by pyrolysis combined with catalysis could be ascribed to the inhibition of precursor formation at 200–300 °C by Pd. Synergistic effect of water washing and catalysis in pyrolysis process at 350 °C reduces the concentrations PCDD/Fs and dl-PCBs to lower than 20 pg WHO-TEQ/g, enabling the reuse of MSW fly ash.

Effects of oil Degradation on Aromatics of some Nigerian oils.

Six Nigerian oils were analyzed using the Gas chromatography mass spectrometry (GC/MS) with the aim of increasing our understanding on the effect of oil biodegradation on aromatic compounds. Results obtained revealed the presence of unresolved complex mixture (UCM) humps in the total ion current (TICs) of all the studied oils consistent with biodegradation. It was also observed that the effect of water washing on the aromatic compounds increases with biodegradation in the studied oils. This is attributed to the fact that biodegradation ensues concurrently with water washing. It was also observed that phenanthrene decreases with biodegradation in all the studied oils, while Methylphenanthrene and Methyldibenzothiophine (MDBT) increases with biodegradation. The studied oils are observed to be at different levels of biodegradation which accounted for the variance seen in some of the results.

Effect of water-washing of wheat straw and hydrothermal temperature on its hydrochar evolution and combustion properties

In order to upgrade wheat straw, hydrothermal treatment at 160–240 °C was investigated. Meanwhile, the influence of temperature and leaching on the fuel’s physicochemical and combustion properties were explored. A temperature of 180–220 °C was found to benefit the generation of hydrochar, with solid and energy yields of at least 57.3% and 69.9%, respectively. When temperature increased to 160 °C, hemicellulose was hydrolyzed and this led to the formation of carbon microspheres. The diameter of the carbon microspheres reached 0.05–0.7 μm. Hydrochars obtained at 160, 180, and 200 °C exhibited better combustion performance with higher comprehensive combustibility index value. While leaching heavily impacted the hydrochar derived at 160 °C and increased its activation energy (178 kJ/mol) above those obtained for treatment at 180 °C (164 kJ/mol) and 200 °C (169 kJ/mol). Overall, the recommended hydrothermal temperature for production of fuel from wheat straw is 180–200 °C.

Water Washing of Fungal-treated Carbonaceous Ores: Effect on Aurocyanide Adsorption by Activated Carbon in CIL Circuit

A typical challenge encountered on most gold processing plants during leaching of refractory ores is the reduction in recovery due to the presence of carbonaceous matter which preg-robs dissolved gold. To reduce preg-robbing during cyanidation, carbonaceous matter has to undergo pretreatment to passivate the active surface. The fungus, Phanerochaete chrysosporium has been shown to biotransform carbonaceous matter, thus reducing its ability to preg-rob gold. However, the possible transfer of entrained fungal biomass into Carbon-In-Leach (CIL) circuits has been reported to decrease the activity of activated carbon, and a proposed solution to this was to wash the fungal-treated material thoroughly with water before CIL operation. This paper therefore set out to assess the effect of water-washing on aurocyanide adsorption by activated carbon in CIL following fungal pretreatment of carbonaceous ores. To realise the objective, activated carbon was contacted with cell-free extract of P. chrysosporium under varying conditions of pH and time, after which it was washed with different volumes of water, and its gold-adsorption ability assessed. The results revealed a decrease in the activity of activated carbon as a function of increasing contact time with the cell-free extract. The percentage decrease was higher after treatment in the acidic medium (13%) than the basic medium (9%). After washing the carbon (treated in acidic medium), gold adsorption was found to increase directly with the volume of water used from 64% at 0 mL to 84% at 500 mL and 91% at 1000 mL. Correspondingly, the carbon treated in basic medium recorded 69% at 0 mL to 87% at 500 mL and 93% at 1000 mL. This paper thus concludes that, sufficient water washing should be employed after fungal-biotransformation of refractory ores before CIL operation to decrease the effect of entrained biomass on the adsorption capacity of activated carbon. Keywords: Carbonaceous Gold Ore, Activated Carbon, Carbon-In-Leach, Cell-Free Extracts

Effect of water-washing on the co-removal of chlorine and heavy metals in air pollution control residue from MSW incineration

The present study systemically investigated the effect of a water-washing process on the removal of harmful chlorides, sulfates, and heavy metals in the air pollution control (APC) residue from municipal solid wastes incineration (MSWI), for sake of a better reuse and disposal of this kind of waste. In addition, the kinetic study was conducted to reveal the releasing mechanism of relevant element in the residue. The results show that, over 70wt.% of chlorides and nearly 25wt.% of sulfates in the residue could be removed by water washing. Based on an economical consideration, the optimal operation conditions for water washing of APC residue was at liquid/solid (L/S) ratio of 3mL:1g and extracting time of 5min. As expected, the concentrations of Co, Cr, Fe, Ni, V and Cu in the washing effluent increased with time during the washing process. However, the extracting regime differs among different heavy metals. The concentrations of Ba and Mn increased firstly but declined afterwards, and concentrations of Pb and Zn gradually declined while Cd and As kept constant with the increase of extracting time. It is worth mentioning that the bubbling of CO2 into the washing effluent is promisingly effective for a further removal of Pb, Cu and Zn. Furthermore, kinetic study of the water washing process reveals that the extracting of heavy metals during water washing follows a second-order model.

Light Hydrocarbon Geochemistry of Oils in the Alpine Foreland Basin: Impact of Geothermal Fluids on the Petroleum System

Oil is produced in the Austrian sector of the Alpine Foreland Basin from Eocene and Cenomanian reservoirs. Apart from petroleum, the basin hosts a significant geothermal potential, which is based on the regional flow of meteoric water through Malmian (Upper Jurassic) carbonate rocks. Oils are predominantly composed of n-alkanes, while some samples are progressively depleted in light aromatic components. The depletion in aromatic components relative to abundant n-alkanes is an effect of water washing. Waters coproduced with oils that are affected by water washing show a progressive reduction in salinity and depletion in 2H and 18O isotopes, indicating that the degree of water washing is mainly controlled by the inflow of meteoric water from the Malmian aquifer. In some fields with Cenomanian reservoir rocks, a hydraulic connectivity with the Malmian aquifer is evident. However, water washing is also recognized in Eocene reservoirs and in areas where the Malmian aquifer is missing. This shows that existing flow models for the regional Malmian aquifer have to be modified. Therefore, the results emphasize the importance of combining data from the petroleum and geothermal industry, which are often handled separately.

Thermogravimetric characteristics and pyrolysis kinetics of high-density-aquacultured Saccharina Japonica: Effects of water-washing

The thermogravimetric characteristics and pyrolysis kinetics of high-density-aquacultured Saccharina japonica were investigated using a thermogravimetric analyzer and micro-tubing reactor, respectively. The effect of water washing S. japonica samples on pyrolysis product distribution was studied at 360, 370 and 380°C with various residence times from 1.0 to 3.0min. The kinetic rate constants of pyrolysis for untreated and water-washed S. japonica samples were determined using nonlinear least-squares regression of experimental data assuming first-order kinetics. The predominant reaction pathway of water-washed S. japonica was liquid to gas product (k3) at each temperature, while that of untreated S. japonica was biomass to liquid product (k2) at 360 and 370°C, then liquid to gas product (k3) at 380°C. However, the k2/k1 ratio of water-washed S. japonica (1.2166–1.3247) was more than two times that of untreated S. japonica (0.5763–0.6346).

A case study of crude oil alteration in a clastic reservoir by waterflooding

The objective of this research was to evaluate the effect of waterflooding on the chemical properties of crude oils. Geochemical characteristics were investigated using GC, GC–MS and stable carbon isotope in 36 oils from three recovery stages spanning an 8-month interval for 12 productive wells in the Qudi oilfield. Waterflooded oils exhibit decreases in aromatics and increases in saturates contents, with an initial increase in NSO content and subsequent decrease; a decrease of ∑n-C21−/∑n-C22+ ratio; a slight more positive stable carbon isotope ratios for the NSO fractions; an increase of 4-MDBT/DBT ratio C158β(H)-drimane/C168β(H)-homodrimane ratio values, which are consistent with the effect of water washing. However, the irregular variation of Pr/n-C17 and pH/n-C18 ratios and the a random change of naphthalene related parameters values imply a complex fluid flow behavior influenced by the strata chromatography adsorption and the change of aqueous solubility for certain compound during the waterflooding development, except the predominant water washing. The source- and maturity-related and unchanged diterpane, triterpane, sterane, phenanthrene, dibenzothiophene, and TAS biomarker parameters are minimally affected or unchanged by waterflooding and, therefore, can be reliably used for its geochemical interpretation.

Comparison of the Adhesive Performances of Soy Meal, Water Washed Meal Fractions, and Protein Isolates

Adhesive bonding of wood plays an increasing role in the forest products industry and is a key factor for efficiently utilizing timber and other lignocellulosic resources. In this work, we obtained five soy meal products through commercial sources or in-house preparations. The protein content was 49.6%, 56.9%, 66.2%, 86.3%, and 91.9% for untreated defatted soy meal, pH 8.5 water washed meal, neutral water washed meal, commercial protein isolate, and in-house prepared protein isolate. The adhesive performances measured by the maximal dry and soaked shear strength of the bonded maple veneers at break were not exactly in the same order of the protein content, indicating that other components (e.g. carbohydrates, metals) might also have played certain roles in the adhesive ability of these products. Data at two press temperatures (i. e. 100, and 130 <sup>o</sup>C) with or without the addition of tung oil revealed that water washed soy meals behaved more like untreated meal than soy protein isolates. This observation is different from a recent report on the effect of water washing on cottonseed meal products. Thus, further elucidation of the mechanisms or causes of the differing effects of water washing would shed light on the adhesive mechanisms of the two types of oilseed meal materials, thus optimizing use of these materials and their fractions for wood bonding.

Effect of water washing on reactivities and NOx emission of Zhundong coals

Zhundong coalfield is one super-huge coalfield newly discovered in China. However, ash-related problems have occurred due to its high content of alkali metals. Water washing is a possible approach to improve its utilization while little research was conducted on Zhundong coals. This study deals with the effect of water washing on alkali metal removal, thermal behaviors, and NOx emission of Zhundong coals. Experimental results show that water-soluble sodium is the predominant chemical form accounting for 70–92% of total sodium, while the case of potassium is different. The pore structure shows a considerable change after being washed. Sodium can be effectively removed while the removal ratio is closely related to water temperature and washing time. The mean apparent activation energy of coal pyrolysis decreases after being washed at low temperature, while high temperature of washing water hinders the pyrolysis. Certain sodium has a catalytic effect on pyrolysis while excessive sodium exhibits inhibitory influence. The conversions of fuel-N to NO and to N2O of washed coals are higher than those of raw coals. Water washing has a slight negative effect on NOx emission and combustion reactivity which is related to the catalytic effect of sodium within coal structure.

Effect of water washing on the thermal behavior of rice straw

Rice straw can be used as a renewable fuel for heat and power generation. It is a viable mean of replacing fossil fuels and preventing pollution caused by open burning, especially in the areas where this residual biomass is generated. Nevertheless, the thermal conversion of rice straw can cause some operating problems such as slag formation, which negatively affects thermal conversion systems. So, the main objective of this research is studying the combustion behavior of rice straw samples collected from various regions by applying thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the thermal behavior of ashes from rice straw was also analyzed in order to detect their melting points, and ash sintering was detected at different temperatures within the range between 550 and 1000°C. Since washing rice straw with water could reduce the content of undesirable inorganic compounds related to the ash fusibility, samples of washed rice straw were analyzed under combustion conditions to investigate its differences regarding the thermal behavior of rice straw. The results showed that rice straw washing led to a significant improvement in its thermal behavior, since it reduced the ash contents and sintering formation.

Effect of water washing on fuel properties, pyrolysis and combustion characteristics, and ash fusibility of biomass

In this study, six biomass fuels are washed with deionized water at different temperatures, by a well designed test setup. The effects of water washing on fuel properties, pyrolysis and combustion characteristics, and ash fusibility of biomass fuels are studied via fuel analysis, thermogravimetric analysis and ash fusion temperature measurements. A better method for evaluating the removal efficiency of element contained in biomass has been proposed. The results show that potassium, sulfur and chlorine contained in biomass, which may be harmful to boiler operation, can be effectively removed by washing. After washing, the hemicellulose and cellulose peaks move apart in the derivative thermogravimetric profile and the devolatilization begins at a higher temperature during pyrolysis and combustion processes. Washing also delays the char combustion. Except for candlenut wood and rice hull, washing significantly increases the ash fusion temperatures for biomass fuels. As water temperature increases, the removal efficiencies of potassium, amorphous silica and ash increase for all the six biomass fuels, and the temperature intervals between the deformation temperature, softening temperature and fluid temperature decrease only for washed samples of wheat straw and corn stalk.

Washing effects on electrochemical performance and storage characteristics of LiNi0.8Co0.1Mn0.1O2 as cathode material for lithium-ion batteries

The effect of water washing on LiNi0.8Co0.1Mn0.1O2 cathode is extensively studied with respect to the electrochemical properties, structural stabilities, and storage characteristics. Water washing can improve the cycling performance and structural stability of LiNi0.8Co0.1Mn0.1O2 material in electrolyte, although with a slight deleterious effect on the capacity. Storage tests of the 4.3 V charged electrodes at 90 °C after 30 days show that Ni, Co, Mn in fresh and washed samples are dissolved in electrolyte, but the amount of dissolved Ni4+ ions after washing decreases by 31.5% compared with the fresh cathode. Moreover, the fresh sample transforms into the spinel phase with a Fd3m space group, whereas the washed sample remains as a layered hexagonal phase with an Rm3¯ space group. FTIR spectroscopy, transmission electron microscope (TEM), X-ray diffraction (XRD) and electrochemical studies indicate that the washed materials become more easily attached upon exposure to air, accompanied by significant increase in cationic disorder and NiO-like cubic phase near surface.

Improved surface wettability of polyurethane films by ultraviolet ozone treatment

AbstractThe wettability of polyurethane (PU) was altered using ultraviolet ozone (UVO) treatment. The effect of UVO treatment on PU surface chemistry was investigated with various experiments. The direct measurement of sessile drops was employed to quantify the static contact angle of different wetting liquids on homogeneous PU films with various UVO treatment times. The contact angle of DI water droplets was decreased to 17.2° from 70.04° after 5 min UVO treatment. The surface free energy of PU films was 51.46 mN m−1 before treatment and was increased to 71.5 mN m−1 after being fully treated. X‐ray photoelectron spectroscopy (XPS) analysis shows a significant amount of polar functional species (CO and CO bonding) were formed on the PU surface by UVO treatment. atomic force microscopy (AFM) characterization shows the PU surface morphology was different before and after UVO treatment. The effect of water washing on UVO treated surface was also investigated. An aging effect study indicates the UVO modification can sustain the improved wettability with limited hydrophobic recovery, where the DI water contact angle remains constant at around 22° after the UVO treatment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effect of water washing on the functional and rheological properties of proteins from threadfin bream (Nemipterus japonicus) meat

SummaryThe effect of the number of water washing cycles on the proximate composition, physicochemical and functional properties of proteins from threadfin bream meat was studied. Contents of proteins, fat, ash and non‐protein nitrogen showed a significant (P < 0.05) decrease with the number of washing cycles. The removal of low molecular weight components and increase in the concentration of high molecular weight components was confirmed by gel filtration profile and sodium dodecyl sulphate polyacrylamide gel electrophoresis. The water absorption, fat absorption and emulsion capacity parameters showed a positive correlation with the number of washing cycles. The gel‐forming ability showed a marked improvement with the number of washing cycles. The dynamic viscoelastic behaviour of unwashed and washed meat showed a structure build‐up reaction and was more pronounced in once washed meat. The flow behaviour of total protein solution from unwashed and washed meat showed a pseudoplastic behaviour.

Volatile Component Analysis of Commercially Milled Head and Broken Rice

ABSTRACT: The volatile components of commercially milled head and broken rice samples and the effect of water washing on volatile components were investigated over 30 d of storage at 37°C and 70% relative humidity. Pentanal, pentanol, hexanal, pentylfuran, octanal, and nonanal were the major volatile components identified by gas chromatography‐mass spectrometry (GC‐MS) analysis in both head and broken rice samples. The concentration of volatile components was greater in broken rice than in head rice and increased significantly during the storage period for both rice types. Water washing was found to be effective in reducing the volatile components for both head and broken rice.

Relative FFA formation and lipid oxidation of commercially milled unseparated, head, and broken rice

AbstractThis study was conducted to determine the relative rate of FFA formation and lipid oxidation of unseparated (head and broken), head, and broken rice and the effect of water washing on the lipid quality of broken rice. A regression model was developed with surface FFA or conjugated diene (CD) content vs. incubation time to determine the rates of FFA formation and lipid oxidation. The surface lipid contents of unseparated, head, and broken rice were 0.40, 0.38, and 0.50% of rice, respectively. FFA formation during storage showed three phases: an initial rapid formation, followed by a period of very little or no formation, and finally a phase of gradual formation. In contrast, CD formation initially showed a slow increase but later increased gradually with storage time. The relative rates of FFA and CD formation of unseparated, head, and broken rice were 0.0028, 0.0027, and 0.0036 and 0.192, 0.188, and 0.377, respectively. Water washing reduced the rates of FFA formation and lipid oxidation of broken rice to 0.0015 and 0.2192 from initial values of 0.0031 and 0.369, respectively. Water washing appears to be a simple and practical means of lowering the rates of FFA formation and lipid oxidation in broken rice.

Effect of water washing on the reduction of surface total lipids and FFA on milled rice

AbstractA simple method for removing total lipids from the rice surface by water washing is described for brewing operations, where small FFA levels can have a considerable effect on end‐product flavor quality. Commercially milled (first‐, second‐, and third‐break) rice was washed with deionized water with constant stirring for 5 and 10 min. About 60 to 80% of total surface lipids were removed by water washing, with a reduction of FFA and conjugated dienes (CD) relative to unwashed control samples. The total surface FFA content of first‐, second‐, and third‐break milled rice was reduced by more than 50% of the original value by washing. Increases in FFA and CD in washed rice after 7 d of storage at 37°C and 70% RH were much lower than those of unwashed controls, in which FFA and CD development was considerably greater and reached brewing quality. Water washing may be a practical means of reducing off‐flavor development in milled rice.