Influence of modified soils on the removal of diesel fuel oil from water and the growth of oil degradation micro-organism

Three soils were modified with two kinds of cationic surfactants in order to increase their sorptive capabilities for organic contaminants. Sorption of diesel fuel oil in water by these modified soils had been investigated. Modified soils can effectively sorb diesel fuel oil from water. The sorption capability of modified soils is: HDTMA-black soil > HDTMA-yellow brown soil > HDTMA-red soil > TMA-black soil > TMA-yellow brown soil > TMA-red soil. Sorption of diesel fuel oil by natural soils and HDTMA modified soils is via partition, the sorption isotherms can be expressed by Henry equation, and logK(SOM) is 2.42-2.80, logK(HDTMA) is 3.37-3.60. Sorption isotherms of TMA modified soils can be expressed by Langmuir equation, the saturation sorption capacities are 1150 (TMA-black soil), 750 (TMA-yellow-brown soil), 171 mg/kg (TMA-red soil), respectively. A diesel fuel oil degradation micro-organism (Pseudomonas sp.) was isolated in the lab. To test the influence of the modified soils on the micro-organism, various growth curves of Pseudomonas in different conditions were drawn. Pseudomonas can grow very well with natural soils and TMA modified soils. The acclimation period of Pseudomonas is reduced. As to HDTMA modified soils, HDTMA loading amount is very important. When HDTMA loading amount is no higher than 0.5 CEC, the micro-organism can grow very well after a long acclimation period.     

Utilization of two invasive free-floating aquatic plants (Pistia stratiotes and Eichhornia crassipes) as sorbents for oil removal

Free-floating aquatic plants Pistia stratiotes and Eichhornia crassipes are well-known invasive species in the tropics and subtropics. The aim of this study was to utilize the plants as cost-effective and environmentally friendly oil sorbents. Multilevel wrinkle structure of P. stratiotes leaf (PL), rough surface of E. crassipes leaf (EL), and box structure of E. crassipes stalk (ES) were observed using the scanning electron microscope. The natural hydrophobic structures and capillary rise tests supported the idea to use P. stratiotes and E. crassipes as oil sorbents. Experiments indicated that the oil sorption by the plants was a fast process. The maximum sorption capacities for different oils reached 5.1–7.6, 3.1–4.8, and 10.6–11.7 g of oil per gram of sorbent for PL, EL, and ES, respectively. In the range of 5–35 °C, the sorption capacities of the plants were not significantly different. These results suggest that the plants can be used as efficient oil sorbents.     

The influence of ceramic-coated piston crown,exhaust gas recirculation,compression ratio and engine load on the performance and emission behavior of kapok oil–diesel blend operated diesel engine in comparison with thermal analysis

In this work, the development and usability of kapok oil in diesel engine was intended. With this purpose, the piston crowns are coated with mullite–lanthanum (ML) ceramic composite at varying compositions in order to reduce the heat rejection during combustion process. The kapok oil is blended with diesel fuel consisting of (20% kapok oil–80% diesel) volumetrically named B fuel. The B and diesel (D) fuels are taken for the engine performance test with different coated piston (ML1, ML2, and ML3) and exhaust gas recirculation (EGR—10%, 20%, and 30%), compression ratio (CR—16, 17, and 18) and engine load (50%, 75%, and 100%). Also, the engine performance study on brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), hydrocarbons (HCs), oxides of nitrogen (NOx), carbon monoxide (CO), smoke opacity, and numerical study using ANSYS software is carried out. When operated with ML2-coated pistons with B fuel, maximum BTE value of 29.2%, minimum BSFC value of 0.224 kg/kW-h, CO emission of 0.2%, and smoke opacity of 39 ppm were observed. The results showed that ML2-coated piston considerably improved the performance of the test engines when compared with ML1 and ML3 coatings. Except for NOx emission, all other pollutant emission values were reduced. The numerical analysis using ANSYS software for ML2-coated pistons showed better retention of in-cylinder chamber temperature.

     

Efficiency of recycled wool-based nonwoven material for the removal of oils from water

The aim of this study was to highlight the potential use of recycled wool-based nonwoven material for the removal of diesel fuel, crude, base, vegetable and motor oil from water. Sorption capacity of the material in water and in oil without water, oil retention, sorbent reusability and buoyancy in static and dynamic conditions were investigated. The results show high sorption capacity of recycled wool for different kinds of oil. This sorbent also exhibited excellent buoyancy after 24h of sorption as well as a good reusability since the decrease in sorption capacity did not exceed 50% of the initial value after five sorption cycles in oil without water.     

Studies on piston bowl geometries using single blend ratio of various non-edible oils

The depletion of fossil fuels and hike in crude oil prices were some of the main reasons to explore new alternatives from renewable source of energy. This work presents the impact of various bowl geometries on diesel engine with diesel and biodiesel samples. Three non-edible oils were selected, namely pumpkin seed oil, orange oil and neem oil. These oils were converted into respective biodiesel using transesterification process in the presence of catalyst and alcohol. After transesterification process, the oils were termed as pumpkin seed oil methyl ester (PSOME), orange oil methyl ester (OME) and neem oil methyl ester (NOME), respectively. The engine used for experimentation was a single-cylinder four-stroke water-cooled direct-injection diesel engine and loads were applied to the engine using eddy current dynamometer. Two bowl geometries were developed, namely toroidal combustion chamber (TCC) and trapezoidal combustion chamber (TRCC). Also, the engine was inbuilt with hemispherical combustion chamber (HCC). The base line readings were recorded using neat diesel fuel with HCC for various loads. Followed by 20% of biodiesel mixed with 80% neat diesel for all prepared methyl esters and termed as B1 (20% PSOME with 80% diesel), B2 (20% OME with 80% diesel) and B3 (20% NOME with 80% diesel). All fuel samples were tested in HCC, TCC and TRCC bowl geometries under standard injection timing and with compression ratio of 18. Increased brake thermal efficiency and reduced brake specific fuel consumption were observed with diesel in TCC geometry. Also, higher heat release and cylinder pressures with lower ignition delay were recorded with TCC bowl geometry. TCC bowl geometry showed lower CO, HC and smoke emissions with B2 fuel sample than diesel and other biodiesel samples. But, higher NOx emission was observed in HCC and TCC than that in TRCC bowl geometry.

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Use of biomass sorbents for oil removal from gas station runoff

The use of biomass sorbents, which are less expensive and more biodegradable than synthetic sorbents, for oil removal from gas station runoff was investigated. A bench-scale flume experiment was conducted to evaluate the oil removal and retention capabilities of the biomass sorbents which included kapok fiber, cattail fiber, Salvinia sp., wood chip, rice husk, coconut husk, and bagasse. Polyester fiber, a commercial synthetic sorbent, was also experimented for comparison purpose. Oil sorption and desorption tests were performed at a water flow rate of 20 lmin-1. In the oil sorption tests, a 50 mgl(-1) of used engine oil-water mixture was synthesized to simulate the gas station runoff. The mass of oil sorbed for all sorbents, except coconut husk and bagasse, was greater than 70%. Cattail fiber and polyester fiber were the sorbents that provided the least average effluent oil concentrations. Oil selectivity (hydrophobic properties) and physical characteristics of the sorbents are the two main factors that influence the oil sorption capability. The used sorbents from the sorption tests were employed in the desorption tests. Results indicated that oil leached out of all the sorbents tested. Polyester fiber released the highest amount of oil, approximately 4% (mass basis) of the oil sorbed.     

Tolerance of the periwinkles Pachymelania aurita (Muller) and Tympanotonus fuscatus (Linne) to refined oils

Tolerance of Pachymelania aurita (Muller) and Tympanotonus fuscatus (Linne) to kerosene, diesel, and gasoline was studied. Emulsions of these refined oils were observed to be more harmful when compared with such oil films on the water surface. T. fuscatus was observed to be less susceptible to such exposures. After 48 h exposure to kerosene, diesel, and gasoline, as an oil film on the water surface, there was no significant difference in the mean survival values obtained for T. fuscatus and P. aurita, respectively. However, the differences in the mean survival values obtained for P. aurita in emulsions of these three refined oils were statistically significant, following a trend of kerosene > diesel > gasoline in order of toxic effects. The values for T. fuscatus showed no significant differences.     

Treatment of oil spill by sorption technique using fatty acid grafted sawdust

Treatment of oil spills remains a challenge to environmental scientists and technologists. Among all the existing techniques used for oil treatment, sorption is a popular technique because it is cheap, simple and effective. Among the various sorbents used, sawdust appears to be the most attractive material in terms of cost, versatility and abundance. In the present work, the efficacy of surface modification of sawdust by fatty acids (oleic acid, stearic acid and decanoic acid) and vegetable oils (castor oil or mustard oil) is demonstrated. Sorption of seawater contaminated with crude oil and also weathered oil was greatly enhanced by the surface modification. The results show that oleic acid grafted sawdust (OGSD) has the best sorption capacity for crude oil as well as weathered oil.     

润滑油废白土的热解处理

以润滑油废白土为原料,利用电热解法,研究了热解终温、加热速率和CaO添加量对热解产物的影响。实验结果表明:热解终温对热解产物的影响最为显著。随着热解终温的升高,不凝气产量和产油率均迅速增加。当热解终温达到600℃时,其增加的速率逐渐缓慢增大。当控制热解终温为800℃、加热速率为16℃/min、CaO添加量为0.5%时,富氢气体产量为189.2 L/kg,气体中主要成分为H2和CH4,其含量分别为27.97%和41.64%;热解残渣含油率和重金属溶出物均低于标准规定值,热解油产率为10.98%,回收率为38.94%,其主要成分为汽油、柴油和重油3部分组成,分别含19.13%、31.35%和49.52%。     

Sorption and desorption behavior of benzidine in different solvent-sediment systems

The sorption and desorption behavior of benzidine in eight solvent-sediment systems were studied using a batch method. The solvents tested included deionized water (DI), calcium chloride solution (CaCl2), sodium hydroxide solution (NaOH), acetonitrile (ACN), a mixture of acetonitrile and ammonium acetate solution (ACN-NH4OAc), methanol (MeOH), ammonium acetate solution (NH4OAc) and hydrochloric acid solution (HCl). Three sets of sorption isotherm experiments were conducted separately in these eight solvents with seven days, three weeks, and two months of contact times, respectively. The results demonstrated nonlinear benzidine sorption phenomena in all eight solvents with higher sorption affinities for sediment sites in the aqueous solvents than in the organic solvents. The results from the desorption experiments revealed that the benzidine desorption efficiencies in the solvents decreased in an order, which was approximately the reverse order of its sorption affinity. Results also suggested that hydrophobic partitioning and covalent binding processes dominated in the desorption experiments, while cation exchange process had little effect on desorption of benzidine. A three-stage model was subsequently applied to simulate the desorption data in the selected solvents of ACN, ACN-NH4OAc and NaOH, respectively. The rapidly desorbing initial fractions were about 0.13-0.20, 0.15-0.26, and 0.18-0.25 for ACN, ACN-NH4OAc and NaOH, respectively. Finally, the sorbed concentrations of benzidine in slowly and very slowly desorbing domains in the selected solvents were correlated with the maximum sorption capacities obtained from the Langmuir sorption isotherm model. The maximum sorption capacities of benzidine were found to be comparable to the amount of benzidine residing in the slowly and very slowly desorbing domains.     

Effective oil removal from water by magnetically driven superhydrophobic and oleophilic magnetic titania nanotubes

Development of efficient techniques to combat the harmful effects of oil spill is an emerging field, where fabrication of new sorbents for selective removal of oil has become a hot topic for environmental scientists. The present study reports the preparation of superhydrophobic/oleophilic magnetic titania nanotubes via a facile hydrothermal method, followed by the treatment with octadecylamine, as potential magnetically driven sorbent for selective removal of oil from water surface. The magnetic nature (superparamagnetism at 300 K) of the nanotubes enabled magnetic removal of the oil-sorbed material from water surface. Wettability test of the material depicted a static water contact angle of 166 ± 1°, indicating its superhydrophobic character. Oil uptake experiments and contact angle measurements revealed its superoleophilicity with maximum oil sorption capacity >1.5 g/g for a variety of oils. In addition to the ease of magnetic removal, the nanotubes possess sufficient buoyancy, high selectivity, and quick rate of oil uptake and is more than five times reusable.     

Enhanced adsorption of hexavalent chromium by a biochar derived from ramie biomass (<Emphasis Type="Italic">Boehmeria nivea</Emphasis> (L.) Gaud.) modified with β-cyclodextrin/poly(L-glutamic acid)

This paper explored biochar modification to enhance biochar’s ability to adsorb hexavalent chromium from aqueous solution. The ramie stem biomass was pyrolyzed and then treated by β-cyclodextrin/poly(L-glutamic acid) which contained plentiful functional groups. The pristine and modified biochar were characterized by FTIR, X-ray photoelectron spectroscopy, specific surface area, and zeta potential measurement. Results indicated that the β-cyclodextrin/poly(L-glutamic acid) was successfully bound to the biochar surface. Batch experiments were conducted to investigate the kinetics, isotherm, thermodynamics, and adsorption/desorption of Cr(VI). Adsorption capacities of CGA-biochar were significantly higher than that of the untreated biochar, and its maximum adsorption capacity could reach up to 197.21 mg/g at pH 2.0. Results also illustrated that sorption performance depended on initial solution pH; in addition, acidic condition was beneficial to the Cr(VI) uptake. Furthermore, the Cr(VI) uptake was significantly affected by the ion strength and cation species. This study demonstrated that CGA-biochar could be a potential adsorbent for Cr(VI) pollution control.     

Heavy metal removal by activated sludge: influence of Nocardia amarae.

The goal of this research was to examine the metal binding capacity of Nocardia amarae cells and to assess the influence of Nocardia cells on the overall metal binding capacity of activated sludge. Metal sorption capacities of the pure Nocardia cells and activated sludge biomass containing various levels of added Nocardia pure cultures were determined by a series of batch experiments. Batch sorption isotherms for nickel (Ni), copper (Cu), and cadmium (Cd) showed that the pure culture of N. amarae exhibited significantly higher metal sorption capacity than the activated sludge biomass obtained from Wilmington Wastewater Treatment Plant (Wilmington, DE). Surface area of biomass estimated by a dye technique showed that pure N. amarae cells growing at stationary phase have substantially more specific surface area than that of activated sludge from Wilmington Treatment Plant. A two-fold difference in specific surface area indicated that the higher metal sorption capacity of Nocardia cells may be due to the higher specific surface area. The metal sorption capacity of activated sludge increased proportionally with the amount of Nocardia cells present in the mixed liquor. This increase was attributed to the greater specific surface area of the mixed liquor samples containing greater amounts of Nocardia cells.     

Investigations on the effect of chlorine in lubricating oil and the presence of a diesel oxidation catalyst on PCDD/F releases from an internal combustion engine

This paper reports on an intensive study into releases of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated furans (PCDF) and polychlorinated biphenyls (PCB) from a diesel engine and the analysis of PCDD/F and PCB in crankcase lubricating oil. Experimental conditions were set and carefully controlled in order to maximize the possible impact of, and our ability to measure the effect of, changes in the levels of chlorine in the lubricant. Emissions to air were measured using modified EPA methods following the principles of the European EN 1948 standards. A series of 40 experimental runs were completed using three reference lubricants formulated to have three levels of chlorine present as a residual component (at levels of 12, 131 and 259 mg kg(-1) or ppm). The engine was run with and without the diesel oxidation catalyst. All lubricants were realistic oils and the use of unrealistic additives or doping of components - particularly chlorine - in the fuel and lubricant was carefully avoided. Analysis of fuel and lubricant (before and after testing) samples required strenuous attention to achieve acceptable recoveries and showed non-detectable levels of PCB and PCDD/F at a detection limit of around 1.5 ng I-TEQ kg(-1) (ppt), indistinguishable from the laboratory blank. The testing demonstrated the need for extreme care to be taken in developing measurement methods that are sufficiently sensitive for measuring chlorine content of fluids and PCDD/F in oils, the latter being particularly challenging. Mean emissions of PCDD/F with the diesel oxidation catalyst in place were 23 pg I-TEQ l(-1) of fuel and with the diesel oxidation catalyst removed 97 pg I-TEQ l(-1) of fuel. The results of this testing showed that the emissions of PCDD/F were greatly reduced by the presence of a diesel oxidation catalyst in the exhaust, a finding that has not been explicitly tested in previous work. They also show that emissions from the engine were not controlled by the level of chlorine in the lubricant and that emissions did not change in response to a much greater step change in the total chlorine entering the combustion chamber due to a change in the level of chlorine in the fuel. Emissions when the engine was configured with a diesel oxidation catalyst showed a consistent pattern that appears to be unique in the experience of the authors.     

Effect of humic acids on physicochemical property and Cd(II) sorption of multiwalled carbon nanotubes

Carbon nanotubes (CNTs), as a type of superior adsorbents for both organic and inorganic contaminants, are increasingly introduced into the environment. Ubiquitous natural organic matter (NOM) would coat on the released CNTs and change their physicochemical properties and sorption of contaminants. The effects of four sequentially extracted humic acids (HAs, as a model NOM) from a peat soil on the physicochemical properties and Cd(II) sorption of three multiwalled CNTs (MWNTs) with different surface areas were investigated. The MWNTs as purchased with very few oxygen-containing functional groups had relatively low sorption capacities (0.93–1.49 mg g⁻¹) for Cd(II) and the sorption capacity increased with increasing surface area of the MWNTs. Surface-coating with the HAs lowered surface areas of the MWNTs but greatly increased their sorption capacities (5.42–18.4 mg g⁻¹). The MWNT-bound HAs introduced oxygen-containing functional groups and negative charges to the MWNT surfaces, which could thus increase the apparent sorption of Cd(II) through chemical complexation and electrostatic attraction, respectively. The later-extracted HAs with lower polarity were more favorable for the surface-coating but increased less Cd(II) sorption by the MWNTs. The results are expected to shed light on understanding the underlying mechanism of the effect of NOM on the sorption of heavy metal ions by CNTs.     

A comparative study on sorption of perfluorooctane sulfonate (PFOS) by chars, ash and carbon nanotubes

Perfluorooctane sulfonate (PFOS), as one of emerging contaminants, has been attracting increasing concerns in recent years. Sorption of PFOS by maize straw- and willow-derived chars (M400 and W400), maize straw-origin ash (MA) as well as three carbon nanotubes (CNTs) was studied in this work. The sorption kinetics of PFOS by the six adsorbents was well fitted by the pseudo-second-order model. CNTs reached equilibrium in 2 h, much faster than those by chars (384 h) and ash (48 h). According to the sorption isotherms, both single-walled carbon nanotubes (SWCNT) and MA had high sorption capacities (over 700 mg g⁻¹), while the two chars had low sorption capacities (below 170 mg g⁻¹) caused by their small BET surface area. In the case of MA, due to its positively charged surface, both hydrophobic interaction and electrostatic attraction involved in the sorption, and the formation of hemi-micelles further favored the sorption. This study suggested that SWCNT and MA were effective adsorbents for PFOS removal from water. Compared to SWCNT, MA is low cost and easy to obtain, so it could be a preferred adsorbent for PFOS removal.     

Use of natural clinoptilolite to improve water quality: sorption and selectivity studies of lead(II), copper(II), zinc(II), and nickel(II).

Natural clinoptilolite can be used as an ion exchanger for removal of heavy metals and treatment of environmental pollution because of its desirable characteristics of high ion exchange selectivity and resistance to different media. In this work, the potential of natural clinoptilolite from G?rdes mines (West Anatolia, Turkey) for the uptake of lead(II), nickel(II), copper(II), and zinc(II), from their single and mixed ion solutions, was evaluated using the batch method. The mineralogical and chemical properties of the sorption material were carried out by X-ray diffraction, X-ray fluoremetry, scanning electron microscopy, and wet analysis. Contact time, initial solution pH, solid-to-liquid ratio, and initial metal cation concentration were determined as single ion sorption parameters. The silicon/aluminum ratio and the theoretical and equivalent exchange capacities, both in single and mixed solutions, were established. Corresponding adsorption constants and distribution coefficients have been found.     

Sorption of 3,4-dichloroaniline on four contrasting Greek agricultural soils and the effect of liming

Sorption of 3,4-dichloroaniline (3,4-DCA) on four typical Greek agricultural soils, with distinct texture, organic matter content and cation exchange capacities, was compared by using sorption isotherms and the parameters calculated from the fitted Freundlich equations. The sorption process of 3,4-DCA to the soil was completed within 48-72 h. The 3,4-DCA sorption on all soils was well described by the Freundlich equation and all sorption isotherms were of the L-type. The sandy clay loam soil with the highest organic matter content and a slightly acidic pH was the most sorptive, whereas the two other soil types, a high organic matter and neutral pH clay and a low organic matter and acidic loam, had an intermediate sorption capacity. A typical calcareous soil with low organic matter had the lowest sorption capacity which was only slightly higher than that of river sand. The 3,4-DCA sorption correlated best to soil organic matter content and not to clay content or cation exchange capacity, indicating the primary role of organic matter. The distribution coefficient (K(d)) decreased with increasing initial 3,4-DCA concentration and the reduction was most pronounced with the highly sorptive sandy clay loam soil, suggesting that the available sorption sites of the soils are not unlimited. Liming of the two acidic soils (the sandy clay loam and the loam) raised their pH (from 6.2 and 5.3, respectively) to 7.8 and reduced their sorption capacity by about 50 %, indicating that soil pH may be the second in importance factor (after organic matter) determining 3,4-DCA sorption.     

Vertical distribution of aliphatic and aromatic hydrocarbons in mussels from the Amposta offshore oil production platform (Western Mediterranean)

The qualitative distributions of aliphatic hydrocarbons in mussels adhered to the legs of an oil production platform (Amposta, Western Mediterranean) have evidenced local (diesel oil) and chronic inputs (middle East crude oils) as the main pollutant sources in the area. Quantitative data have shown that aromatic hydrocarbons are selectively accumulated with the age of mussels and are more evenly distributed through the water column. Background concentrations of petrogenic aliphatic hydrocarbons in mussels living in the vicinity of oil platforms have been established in the range of 25–40 ug/g dry weight.     

Experimental investigation of tribological characteristics and emissions with nonedible sunflower oil as a biolubricant

Plant (vegetable) oil has been evaluated as a substitute for mineral oil–based lubricants because of its natural and environmentally friendly characteristics. Availability of vegetable oil makes it a renewable source of bio-oils. Additionally, vegetable oil–based lubricants have shown potential for reducing hydrocarbon and carbon dioxide (CO₂) emissions when utilized in internal combustion (IC) engines and industrial operations. In this study, sunflower oil was investigated to study its lubricant characteristics under different loads using the four-ball tribometer and the exhaust emissions were tested using a four-stroke, single-cylinder diesel engine. All experimental works conformed to American Society for Testing and Materials standard (ASTM D4172-B). Under low loads, sunflower oil showed adequate tribological characteristics (antifriction and antiwear) compared with petroleum oil samples. The results also demonstrated that the sunflower oil–based lubricant was more effective in reducing the emission levels of carbon monoxide (CO), CO₂, and hydrocarbons under different test conditions. Therefore, sunflower oil has the potential to be used as lubricant of mating components.

Implications: An experimental investigation of the characteristics of nonedible sunflower oil tribological behaviors and potential as a renewable source for biofluids alternative to the petroleum oils was carried out. The level of emissions of a four–stroke, single-cylinder diesel engine using sunflower oil as a biolubricant was evaluated.