Washing Conditions Research Articles

A Soluble Humic Substance for the Simultaneous Removal of Cadmium and Arsenic from Contaminated Soils.

With abundant oxygen-containing functional groups, a humic substance (HS) has a high potential to remediate soils contaminated by heavy metals. Here, HS was first extracted from a leonardite and analyzed for its chemical compositions and spectroscopic characteristics. Then it was assessed for its ability as a washing agent to remove Cd and As from three types of soils (red soil, black soil, and fluvo-aquic soil) that were spiked with those contaminants (Cd: 40.5–49.1 mg/kg; As: 451–584 mg/kg). The operational washing conditions, including the pH and concentration of the HS, washing time and cycles, and liquid–soil ratio, were assessed for Cd and As removal efficiency. At pH 7, with an HS concentration (3672 mg C/L) higher than its critical micelle concentration and a liquid–soil ratio of 30, a single washing for 6–12 h removed 41.9 mg Cd/kg and 199.3 mg As/kg from red soil, 33.5 mg Cd/kg and 291.5 mg As/kg from black soil, and 30.4 mg Cd/kg and 325.5 mg As/kg from fluvo-aquic soil. The removal of Cd and As from the contaminated soils involved the complexation of Cd and As with the carboxyl and phenolic groups of HS. Outcomes from this research could be used to develop a tailor-made HS washing agent for the remediation of Cd- and As-contaminated soils with different properties.

Sterilization efficiency of pathogen-contaminated cottons in a laundry machine.

Pathogenic bacteria on abiotic surfaces such as fabrics, bedding, patient wears, and surgical tools are known to increase the risk of bacterial diseases in infants and the elderly. The desiccation tolerance of bacteria affects their viability in cotton. Thus, washing and drying machines are required to use conditions that ensure the sterilization of bacteria in cotton. The objective of this study is to determine the effects of various sterilization conditions of washing and drying machines on the survival of three pathogenic bacteria (Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus) commonly presented in contaminated cotton and two non-pathogenic bacteria (Bacillus subtilis and Escherichia coli) in cotton. High survival rates of A. baumannii and S. aureus in desiccated cotton were observed based on scanning electron microscope and replicate organism direct agar contact assay. The survival rates of A. baumannii and S. aureus exposed in desiccated cotton for 8 h were higher (14.4 and 5.0%, respectively) than those of other bacteria (< 0.5%). All tested bacteria were eradicated at low-temperature (< 40°C) washing with activated oxygen bleach (AOB). However, bacterial viability was shown in low temperature washing without AOB. High-temperature (> 60°C) washing was required to achieve 99.9% of the sterilization rate in washing without AOB. The sterilization rate was 93.2% using a drying machine at 60°C for 4 h. This level of sterilization was insufficient in terms of time and energy efficiency. High sterilization efficiency (> 99.9%) at 75°C for 3 h using a drying machine was confirmed. This study suggests standard conditions of drying machines to remove bacterial contamination in cotton by providing practical data.

Arsenic Removal from Contaminated Soil Inside Non-Ferrous Metal Smelter by Washing

ABSTRACT Orthogonal and single-factor experiments were used to investigate the remediation effect of single and mixed washing on arsenic-contaminated soil from a typical non-ferrous metal smelter. The optimal washing conditions, washing kinetics and speciation distribution of arsenic were determined. The obtained removal efficiencies of arsenic in the soil is 83.65%, which could be remedied to less than “ risk intervention values (As < 140 mg·kg−1) for soil contamination of the development land” in soil environmental quality standard China (GB36600-2018) when the mixed ratio of Citric acid (1 mol·L−1) & Rhamnolipid (1%) is 2:1, the ratio of liquid-solid is 15:1 and the washing time is 393 min. The repair effect of mixed washing was significantly higher than the single washing agents, and the washing kinetics was a heterogeneous diffusion process, which was consistent with Elovich model. In addition, mixed washing agents can effectively remove active and potential bioavailable arsenic from soil, which greatly reduces their bioavailability and environmental risk.

Salmonella inactivation and cross-contamination on cherry and grape tomatoes under simulated wash conditions

Washing in chlorinated water is widely practiced for commercial fresh produce processing. While known as an effective tool for mitigating food safety risks, chlorine washing could also represent an opportunity for spreading microbial contaminations under sub-optimal operating conditions. This study evaluated Salmonella inactivation and cross-contamination in a simulated washing process of cherry and grape tomatoes. Commercially harvested tomatoes and the associated inedible plant matter (debris) were differentially inoculated with kanamycin resistant (KanR) or rifampin resistant (RifR) Salmonella strains, and washed together with uninoculated tomatoes in simulated packinghouse dump tank (flume) wash water. Washing in chlorinated water resulted in significantly higher Salmonella reduction on tomatoes than on debris, achieving 2–3 log reduction on tomatoes and about 1 log reduction on debris. Cross-contamination by Salmonella on tomatoes was significantly reduced in the presence of 25–150 mg/L free chlorine, although sporadic cross-contamination on tomatoes was detected when tomatoes and debris were inoculated at high population density. The majority of the sporadic cross-contaminations originated from Salmonella inoculated on debris. These findings suggested that debris could be a potentially significant source of contamination during commercial tomato washing.

Pretreatment of municipal solid waste incineration fly ash and preparation of solid waste source sulphoaluminate cementitious material

Municipal solid waste incineration fly ash (MSWI-FA) is a kind of hazardous waste, and it is of great significance to treat it harmlessly and resourcefully. This study proposes the preparation of sulphoaluminate cementitious materials using water-washed MSWI-FA, flue-gas desulfurization gypsum, and aluminum ash. The changes in the composition and morphology of MSWI-FA before and after washing were investigated, and the effects of various washing conditions on the removal rate of chloride salt from MSWI-FA were analyzed. The effect of firing temperature on the mineral content of the sulphoaluminate cementitious material was also investigated. In addition, the strength and heavy metal leaching characteristics of the corresponding materials were tested. The results show that more than 90% of chloride salts were removed by water washing MSWI-FA two times. Using MSWI-FA as the main raw material, the sulphoaluminate cementitious material containing mostly calcium sulphoaluminate and dicalcium silicate could be prepared successfully at 1270 °C; the amount of MSWI-FA in the raw material can be as high as 35% (dry weight). Moreover, the sulphoaluminate cementitious material can effectively solidify heavy metals in the raw materials. The leaching concentrations of eight heavy metal ions, i.e., Cu, Zn, Cd, Pb, Cr, Ni, Ba, and As are far lower than the concentration limits set by national standards.

Промывка смешанного сульфатного мыла нейтрализованной кислой водой

Sulfate soap, being a valuable by-product of pulp production by the sulfate process, is a mixture of saponified resin and fatty acids and unsaponifiables (sterols, fatty alcohols, aliphatic hydrocarbons, etc.). Sulfate soap micelles enlarge and during surfacing may entrain a portion of black liquor containing dissolved lignin, as well as impurities of calcium compounds; when settling the liquor formed in pulp washing. The main method of removing black liquor is additional settling of sulfate soap prior its processing. It is reasonable and cost effective to use for washing a solution of salts formed in decomposition of soap or spent acid neutralized to pH = 8–14. The article shows the necessity of washing of sulfate soap obtained from different wood species in pulping. Neutralized spent acid received in soap decomposition was used as a washing solution in an amount of 10, 20, and 30 % of sulfate soap volume. Washing was carried out at a temperature of 20–80 °C. The optimal conditions for mixed sulfate soap washing were determined: temperature (20–40 °C), and flow rate of the washing solution (10–20 %). It was found that under optimal washing conditions of mixed sulfate soap with neutralized spent acid, the yield of crude tall oil and its acid number increase, the alkali and lignin content decrease, and the decrease of resin acids in tall oil is prevented.For citation: Starzhinskaya E.V., Kryazhev A.M., Tret’yakov S.I., Glukhanov A.A. Mixed Sulfate Soap Washing with Neutralized Spent Acid. Lesnoy Zhurnal [Forestry Journal], 2019, no. 5, pp. 194–202. DOI: 10.17238/issn0536-1036.2019.5.194

Nitrogen-doped mesoporous graphene with fine-tuned pore size in a few nanometer-scale for supercapacitor applications

Nitrogen-doped mesoporous graphene (NMG) was successfully synthesized by a soft-template method, using graphite oxide (GO) and triblock copolymer (Pluronic P123) in the presence of ammonia water. To finely tune the porous nature through controlling the micellization behaviour of P123, the mesostructured graphenes were washed under different washing conditions. As a result, the synthesized NMGs exhibit 3D porous structure with high surface area (941–1297 m2 g−1) as well as fine-tuned pore size (4.4–11.2 nm) at a few-nanometer scale. Also, to find the optimal temperature for the best supercapacitor performance, the annealing temperature was regulated at 500 °C, 700 °C, and 900 °C. The content and configuration of nitrogen in NMG were rationally controlled as a function of annealing temperature, which strongly influences the electrical conductivity and supercapacitor performance. The highest capacitance of 284 F g−1 was achieved for NMG calcined at 700 °C with a current density of 0.1 A g−1. Furthermore, it shows good cycle stability with ~98% retention of its initial capacitance at a current density of 3.0 A g−1, even after 5000 cycles.

Soil washing remediation of heavy metal from contaminated soil with EDTMP and PAA: Properties, optimization, and risk assessment

Soil washing is a rapid and efficient remediation technique for soil contaminated by heavy metals. In this study, Cd, Pb, and Zn were removed from contaminated soil by ethylenediamine tetra (methylene phosphonic acid) (EDTMP) and polyacrylic acid (PAA). We then investigated the effect of varying the concentration, pH and duration of the washing processes. Single-factor experiments suggest that the PAA washing process may be dominated by electrostatic adsorption, and is suitable for remediation under weak acid and neutral conditions. Meanwhile, EDTMP remediation might be dominated by chelation, which is favorable in strong acid and alkaline environments. In a quadratic saturation D-optimization design (QSDD), we optimized the washing parameters and further explored the washing mechanism including primary factor, principal effect, interaction effect, and the optimal washing conditions, with simultaneously changing multiple influencing factors. The optimum efficiencies of Cd, Pb, and Zn removal were 92.74%, 96.14%, and 50.76% respectively in EDTMP remediation, and 84.62, 79.24, and 41.66% respectively in PAA remediation. The washing processes effectively reduced the availability of Cd, Pb, and Zn in contaminated soil, without noticeably affecting soil chemical properties. Therefore, the washing incurred little ecological risk. EDTMP and PAA are suitable remediation agents of soil contaminated by heavy metals.

Evaluating rhamnolipid-enhanced washing as a first step in remediation of drill cuttings and petroleum-contaminated soils

Environmental pollution by petroleum hydrocarbons (PHCs) is a severe and widespread problem impacting human health and the environment. To combat this issue, innovative and sustainable treatment methods are required. This research study investigated rhamnolipid-enhanced washing of drill cuttings and petroleum-contaminated soil obtained from northeastern British Columbia in Canada. The efficiency of PHC reduction was analysed and quantified via a Gas Chromatography equipped with a Flame Ionization Detector. Optimum washing conditions for both drill cuttings and petroleum-contaminated soil were temperature of ∼23.5 °C (room temperature), rhamnolipid concentration of 500 mg/L, and a washing time of 30 min. The optimum stirring speed and solution-to-sample ratio for drill cuttings and petroleum-contaminated soil were 100 rpm; 1:1, and 200 rpm; 4:1 respectively. The maximum PHC reduction recorded for total petroleum hydrocarbon and PHC fractions – F2, F3 and F4 were 76.8%, 85.4%, 71.3% and 76.9% respectively for drill cuttings and 58.5%, 48.4%, 63.5% and 59.8% respectively for petroleum-contaminated soil. The results strongly suggest that soil washing is an effective step in the reduction of PHC and can be used as a first step in the treatment of drill cuttings and petroleum-contaminated soils.

The use of redox potential to estimate free chlorine in fresh produce washing operations: Possibilities and limitations

Maintaining free chlorine (FC) residual at appropriate pH values is a control approach used to prevent pathogen cross-contamination during tomato dump tank handling and fresh-cut produce washing operations. Oxidation reduction potential (ORP) is a rapid measurement of oxidant-based sanitizer strength, and has been used to estimate FC residual. However, factors, in addition to FC and pH, which influence ORP are not fully understood. This study examined the relationship between ORP and FC under chlorine demand (CLD) free conditions and during fresh produce washing. An equation predictive of FC was developed in the form logFC = f(ORP, ORP2, ORP.pH). A good correlation between ORP and logFC was maintained when other variables changed, but the resulting ORP-logFC curve changed (slope, intercept). A decrease in pH or temperature led to an increase in ORP. Using tap water to wash the produce instead of distilled water significantly changed the ORP. For different types of tested produce, i.e., fresh-cut carrot, onion, romaine and iceberg lettuce, and for whole tomatoes, increasing the product-to-water ratio (i.e., increasing the organics transferred into the water) led to a decrease in ORP for a specific FC residual. The choice of acidulant during washing also influenced ORP. Overall, the correlation of ORP with logFC is more reliable at the lower end (5 mg/L FC) than at the higher end (100 mg/L FC) of the FC range used in fresh produce washing. However, since the ORP in fresh produce wash water is affected significantly in multiple ways by the wash water and process conditions, the predicted FC values with ORP under certain fresh-cut produce washing conditions cannot be generalized for other conditions.

Precipitated K-Promoted Co–Mn–Al Mixed Oxides for Direct NO Decomposition: Preparation and Properties

Direct decomposition of nitric oxide (NO) proceeds over Co–Mn–Al mixed oxides promoted by potassium. In this study, answers to the following questions have been searched: Do the properties of the K-promoted Co–Mn–Al catalysts prepared by different methods differ from each other? The K-precipitated Co–Mn–Al oxide catalysts were prepared by the precipitation of metal nitrates with a solution of K2CO3/KOH, followed by the washing of the precipitate to different degrees of residual K amounts, and by cthe alcination of the precursors at 500 °C. The properties of the prepared catalysts were compared with those of the best catalyst prepared by the K-impregnation of a wet cake of Co–Mn–Al oxide precursors. The solids were characterized by chemical analysis, DTG, XRD, N2 physisorption, FTIR, temperature programmed reduction (H2-TPR), temperature programmed CO2 desorption (CO2-TPD), X-ray photoelectron spectrometry (XPS), and the species-resolved thermal alkali desorption method (SR-TAD). The washing of the K-precipitated cake resulted in decreasing the K amount in the solid, which affected the basicity, reducibility, and non-linearly catalytic activity in NO decomposition. The highest activity was found at ca 8 wt.% of K, while that of the best K-impregnated wet cake catalyst was at about 2 wt.% of K. The optimization of the cake washing conditions led to a higher catalytic activity.

Effects of biodegradable chelator combination on potentially toxic metals leaching efficiency in agricultural soils

Soil washing with chelators, a viable method for treating soils contaminated with potentially toxic metals, has drawn increasing attentions. The objective of this study was to determine a new generation of mixed degradable chelating agents from N, N-bis (carboxymethyl) glutamic acid (GLDA), [S, S]-stereoisomer of ethyleneiaminedisucc--inic acid (EDDS), nitrilotriacetic acid (NTA), and citric acid (CA), and to evaluate its effectiveness and feasibility to reduce toxic metals contamination in two different agricultural soils. A comparative leaching test conducted on the four individual degradable chelating agents showed that the capacity of single chelator in mobilizing copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) varied significantly. Using a combination of GLDA and NTA was more advantageous than using a single chelating agent in extracting potentially toxic metals. The removal efficiencies of Cu, Zn, Cd, and Pb reached 38.2, 9.8, 71.4, and 19.5% for soil 1, and 25.0, 5.2, 59.7, and 18.5% for soil 2, respectively, at mixed chelator (MC) concentrations of 3 mmol/L (GLDA) and 2 mmol/L (NTA), pH of 6.0, and a contact time of 4.0 h. The effects of washing conditions, chelator concentration, pH values, and contact time on the removal efficiencies of target toxic metals were investigated. The results showed that the combined chelating agent has a lower pH dependence, making it feasible for a wider range of applications. The effects of the chelating agents on the morphological distribution of potentially toxic metals and the soil enzyme activity before and after the treatments were also studied. After washing, the content of the water-soluble, acid-soluble, reducible, and oxidizable target metals showed a certain degree of decrease. Although the activities of catalase, urease, and invertase appeared to be inhibited during a short period of time, their activities were stimulated and later promoted with the degradation of the chelating agent. In general, the chelating agent combination has a great potential for toxic metals leaching.

STUDIES TO EVALUATE THE PUTATIVE BINDING OF THE TAU POSITRON EMISSION TOMOGRAPHY TRACER 18F-AV-1451 TO MONOAMINE OXIDASE-B (MAO-B)

Although MAO-B inhibitors selegiline (deprenyl) and rasagiline have been reported not to block 18F-AV-1451 binding in clinical studies, other researchers have reported 3H-AV-1451 binding to MAO-B with nanomolar affinity in in vitro binding studies. In light of these contrasting data, we conducted an extensive set of experiments to investigate potential MAO-B liability for 18F-AV-1451. Equilibrium dissociation constants (Kd) for compound binding to recombinant MAO-B were determined by filtration binding. Nonspecific binding was defined as the binding of the ligand to control microsomes lacking MAO-B. Bound ligand was measured by Liquid Chromatography - Mass Spectrometry (LC-MS) for cold compounds and by gamma counter for F18-ligands. IC50s for each compound were determined in an LC-MS Safinamide:MAO-B competition binding assay. 18F-AV-1451 autoradiography blocking studies were performed on normal tissue with MAO-A/B inhibitors using mild washing conditions. No direct binding of AV-1451 to recombinant MAO-B was detected by radioligand binding or by LC-MS for 1 nM to 15 μM AV-1451. Using the same conditions, the binding of a control MAO-B ligand safinamide was determined to be 57 nM Kd. Evidence of potential AV-1451 interaction with recombinant MAO-B was observed by the weak inhibition by AV-1451 of the binding of safinamide to MAO-B (1.3 μM IC50). By autoradiography, 18F-AV-1451 binding is observed only on tau rich AD tissue and not on normal control tissue when stringent wash conditions are used (i.e. 30% and 70% EtOH) . However, when mild aqueous wash conditions are used, some off-target binding is observed on both AD and normal tissue. Weak blocking of off target 18F-AV-1451 binding on normal tissue was observed for MAO-B inhibitors deprenyl and safinamide (IC50 > 10 μM). There is limited evidence of AV-1451 binding to MAO-B that would impact in vivo 18F-AV-1451 PET imaging as demonstrated by the lack of direct in vitro binding of AV-1451 to recombinant MAO-B, the weak inhibition by AV-1451 of safinamide: MAO-B binding, and the reported lack of effect of MAO-B inhibitor treatment on 18F-AV-1451 PET signal in patients treated with selegiline or rasagiline.

Stability studies of an amylase and a protease for cleaning processes in the food industry

An α-amylase and a protease suitable to be used as detergent additives in Cleaning-In-Place processes in the food industry have been studied in terms of their stability during storage as well as under washing conditions. Enzymatic solutions have been prepared with addition of two non-ionic surfactants at the pH of operation, an amine oxide and an alkylpolyglucoside. Activity assays have been carried out in order to obtain deactivation kinetics. The study of stability at storage during 21 days at 40°C and 60°C reveals that the enzymatic solutions in the absence of surfactants preserve their activity for longer. The protease showed to be more sensitive to thermal deactivation, undergoing a complete loss of activity at 60°C before 24h in all solutions studied. On the other hand, activity assays have been carried out at concentrations, time and temperature values usually found during cleaning processes of hard surfaces. The presence of the alkylpolyglucoside showed to preserve enzymatic activity of α-amylase at all temperatures assayed. The amine oxide, nevertheless, seemed to contribute to α-amylase deactivation and did not have a significant effect on protease. The results of this work suggest the need of stabilize enzymes in detergent formulations even when they do not contain potential denaturants.

Fluid Phase Simulation and Evolution of a Condensate Gas Reservoir in the Tazhong Uplift, Tarim Basin

The fluid phase and the evolution of the condensate gas reservoir in the Lianglitage Formation (O3), Well ZG7-5, Tazhong Uplift, were studied by integrating the PVTsim and the PetroMod software. The fluid phase was successfully simulated, and the burial, temperature, pressure, and pressure coefficient histories were reconstructed. The evolution of the fluid phase and its properties (density, viscosity, and gas-oil ratio) under the ideal and gas washing conditions was also explored. The simulated pressure-temperature (P‐T) phase diagram confirms that the reservoir fluid is in the condensate gas phase at present, with an order of critical point-cricondenbar-cricondentherm (CP‐Pm‐Tm). The temperature and pressure show an overall increasing trend considering the entirety of geological evolution. Under ideal conditions, fluid transition from coexisting gas and liquid phases to a single condensate gas phase occurred during the Late Cretaceous (80 Ma, T=135.7°C, and P=58.19 MPa). The density and viscosity of the liquid phase decreased gradually while the density and viscosity of the gas phase and the solution gas-oil ratio increased during geological processes. With the consideration of gas washing, the critical phase transition time points for 100% and 50% gas washing fluid are 394 Ma, 383 Ma, 331 Ma, and 23 Ma, as well as 266 Ma and 23 Ma, respectively. The average liquid phase density, gas phase density, and liquid phase viscosity under 100% gas washing are larger than those under 50% gas washing before 23 Ma (Miocene), while the gas phase viscosity values are similar for both cases. This study visually suggests that the temperature and pressure histories, which are controlled by the burial history and heat flow evolution, and gas washing have significant impacts on the formation of the condensate gas reservoirs and evolution of the fluid phase and its features in the Tazhong Uplift.

Interactions of arabinogalactans with bacterial cellulose during its synthesis: Structure and physical properties

Arabinogalactans (AGs) are plant cell wall constituents, some of which find applications in the food industry. However, there is very limited information about the interactions of AGs with other plant polysaccharides, in particular with cellulose. In the present work, we studied the interactions of two types of AGs, of different botanical origin and Ara/Gal ratio, with cellulose during and after its synthesis by Komagataeibacter xylinus (ATCC 53524). Solution depletion experiments and quartz crystal microbalance with dissipation monitoring show that these two kinds of AG are able to bind reversibly to pre-made cellulose, as also reflected by their relative incorporation in self-assembled composites during cellulose synthesis, with values of 18.0% (w/w) for acacia AG (Ara:Gal 1:0.9) and 29.1% (w/w) for larch AG (Ara:Gal 1:1.3). In composites, neither AG was rigid or affected cellulose crystallinity as shown by 13C NMR, and did not change the microstructure of the cellulose network as observed using scanning electron microscopy. AG was depleted from cellulose composites under water washing conditions, suggesting that there were only weak bonds between AGs and cellulose. The de-binding behaviour was controlled by surface permeability as indicated by fitting to diffusion models. Incorporation of arabinogalactans in cellulose networks impacts the mechanical and rheological properties of the composites, in part due to dilution of the cellulose concentration in composites.

Promiscuity of host cell proteins in the purification of histidine tagged recombinant xylanase A by IMAC procedures: A case study with a Ni2+-tacn-based IMAC system

Determination of the extent of host cell protein (HCP) contamination is an essential pre-requisite to validate the chromatographic purification of recombinant proteins. This study explores how different experimental conditions affect the HCP profiles generated during the immobilised metal ion affinity chromatographic (IMAC) purification with a Ni2+-1,4,7-triaza-cyclononane (tacn) Sepharose FF™ sorbent of the Bacillus halodurans N- and C-terminal His6-tagged xylanase A, expressed by Escherichia coli BL21(DE3) cells, and captured directly from cell lysates. Comparative studies were also carried out under identical loading, wash and elution conditions using nitrilotriacetic acid (NTA), also immobilised onto an agarose support and complexed with Ni2+ ions. High-resolution tandem mass spectrometry of the tryptic peptides derived from the proteins present in the IMAC flow-through, wash and elution fractions confirmed that the E. coli BL21(DE3) HCP profiles were dependent on the choice of adsorbent. With feedstocks containing the N- or C-terminal His6-tagged xylanase A, in several instances the same E. coli BL21(DE3) HCPs were found to co-elute with the tagged protein from either adsorbent, indicating a preferential ability of some HCPs to bind to both the IMAC resin and to the recombinant protein. This promiscuous behaviour has been found to be due to factors other than just the presence of histidine-rich motifs within the amino acid sequences of these HCPs. This case study demonstrates that the choice of protein expression and separation conditions impact on the levels of HCP contamination when different IMAC systems are employed.

Oil recovery from drilling cuttings by biosurfactant from kitchen waste oil

ABSTRACT The maximum biosurfactant concentration of 5.98 g L−1 was achieved from kitchen waste oil by Pseudomonas aeruginosa. Then, biosurfactant was extracted from the broth and applied to wash oil-based drilling cuttings. Effect rules of six parameters on oil recovery were investigated separately, and the main influencing factors of concentration, pH, and temperature were screened out by Plackett-Burman design. And then the oil washing conditions were optimized by response surface method. The maximum recovery rate was predicted to be 70.48% with the relative error less than 0.006%. The results indicating promising prospect of biosurfactant application in industrial oil recovery.

In vitro efficacy of antifungal agents alone and in shampoo formulation against dandruff‐associated Malassezia spp. and Staphylococcus spp.

Dandruff is a complex skin condition characterized by unpleasant itching and flaking of the scalp. It is primarily attributed to the over colonization of Malassezia yeasts such as Malassezia globosa and Malassezia restricta. Some studies also suggest the involvement of staphylococci bacteria in dandruff disease pathogenesis. We aimed to access the effectiveness of anti-dandruff treatments by determining the efficacy of the active antifungal agents alone or in commercial shampoo formulations against Malassezia and Staphylococcus. The minimum inhibitory concentrations of three anti-dandruff shampoo antifungals (zinc pyrithione, ketoconazole and ciclopirox) and the witch hazel extract, hamamelitannin were tested against commensal Malassezia and Staphylococcus species using broth microdilution methods. In experiments simulating shampoo exposure and washing conditions on the scalp, we also tested the ability of the above agents in shampoo formulation (Head and Shoulders® (H&S), Ketomed® , Sebiprox® , Erol Healthcare Hair Shampoo® respectively) along with a generic over-the-shelf shampoo to inhibit microbial growth. Ketomed® and H&S shampoo were the most effective treatments against Malassezia in invitro assays and washing simulation experiments. Erol Healthcare Hair Shampoo® was less effective against Malassezia as it required a longer contact time to achieve growth inhibition for some species. Sebiprox® showed variable efficacy in washing and contact time experiments whereas the generic over-the-shelf shampoo was the least effective in inhibiting Malassezia and Staphylococcus growth. From these findings, it is reasonable that patients with dandruff may benefit from applying specific antifungal shampoo although results may vary with microbial species, time of contact and shampoo formulation components.

Flame Retardancy, Physiological Comfort and Durability of Casein Treated Cotton Fabrics

The present work was aimed to develop the flame retardant textiles for prevention of second-degree burn injuries from low intensity heat flux accidents. The different concentration of casein suspension was applied on cotton fabrics and their thermo-oxidative properties, flame retardant behavior as well as physiological comfort were examined. From thermo gravimetric analysis, the percentage increase in char residue indicated improvement in thermo-oxidative properties. The maximum improvement in flame retardant behavior was found in case of 30 w/v% casein suspension due to higher production of thermally stable char. Their SEM micrographs also showed the formation of stronger and coherent char with presence of local intumescence. Furthermore, for estimating small differences in burn length and burn area, the flame propagation was studied in detail using the image analysis. The lower concentration of casein below 20 w/v% was found to provide adequate flame retardancy with acceptable physiological comfort and mechanical properties. Finally, the short term durability of casein treatment was verified under the effect of washing and ageing conditions.