Water-soluble Inorganic Salts Research Articles

Ambient PM2.5 components might exacerbate bone loss among middle-aged and elderly women: evidence from a population-based cross-sectional study.

Previous studies have primarily focused on the links between fine particulate matter (PM2.5) and bone health among the general population instead of PM2.5 components and the specific population. We aimed to investigate the associations between PM2.5 components and bone health among middle-aged and elderly women. A total of 748 middle-aged and elderly women were randomly sampled from 32 streets/villages in Hubei Province. The concentrations of ambient PM2.5 and its components were extracted across various residential areas from the Tracking Air Pollution in China (TAP) dataset. Bone mineral density measurements were obtained from dual-energy X-ray absorptiometry scans of study participants. Multivariable logistic and linear models were employed to assess the relationship between PM2.5 and its components and bone loss. Per interquartile range (IQR) increase in nitrate (NO3-) and ammonium (NH4+) concentrations were associated with 1.65 [95% confidence intervals (CI): 1.13, 2.30] and 1.77 (95% CI: 1.26, 2.49) times higher odds of osteoporosis, respectively. Long-term exposure to sulfate (SO42-), NO3-, and NH4+ was negatively associated with T-scores and bone mineral density in L1-L4 lumbar vertebrae. In addition, the elderly, women who have experienced menarche after the age of 14, and postmenopausal women were more susceptible to the water-soluble inorganic salts of PM2.5. The study emphasizes the need for comprehensive policies addressing air quality, with a specific focus on vulnerable populations such as middle-aged and elderly women. Public health interventions aimed at reducing ambient PM2.5 concentrations and minimizing exposure to its harmful components are crucial in mitigating the adverse impact on skeletal health and improving the overall well-being of communities.

Insight into Secondary Inorganic Aerosol (SIA) production enhanced by domestic ozone using a machine learning technique

Taiwan has prioritized management and air pollution control of ozone in the past decade. Atmospheric ozone reacts with gaseous precursors to produce secondary inorganic aerosols (SIAs), which worsen air quality to a great extent. The present study applied a bivariate polar plot, K-means clustering, and a nonlinear autoregressive network with exogenous input neural network (NARX-NN) to identify the sources of O3 and the formation mechanism of SIAs in an urban area, aiming to facilitate the development of exposure risk assessment methods and an O3 pollution early warning system for human health protection. Results show that the present NARX-NN model could be used to capture 72 h ahead of water-soluble inorganic salts (WIS) and O3 concentrations accurately with R2 of 0.71 for NO3-, 0.72 for SO42-, 0.80 for NH4+, and 0.79 for O3 concentrations. Based on the statistical and K-means clustering analysis, the domestic high O3 hours in a year (O3 concentrations>60 ppb) account for up to 76% and 99% of the total high O3 hours in northern and southern Taiwan, respectively. Under volatile organic compounds (VOCs)-limited regime, an increase in O3 concentrations by 57.4% was found to enhance heterogeneous oxidation reaction to produce SIAs by 48.0% of NO3- and 56.6% of SO42- under prevailing northeast monsoon during winter and spring seasons. It is evident that strict control measures are still necessary for local ozone sources to maintain air quality. The source tracing framework developed in the present study is applicable for policymakers to develop early warning systems and maintain air quality during the decision-making process.

Significant impact of water-soluble organic matter on hygroscopicity of fine particles under low relative humidity condition

Uncertainties in estimating the hygroscopicity of bulk aerosols under conditions of low relative humidity (RH) or below the deliquescent RH (DRH) of aerosols remain to be significant, mainly due to the presence of water-soluble organic matter (WSOM). To quantify the contributions of WSOM to aerosol hygroscopicity and associated uncertainties, a field campaign was conducted to measure the hygroscopic growth curve (f(RH)) of bulk aerosols online, dominant chemical compositions in PM2.5 online and offline, and size distributions of the dominant chemical compositions offline during the dry and wet seasons of 2019–2020 in urban Guangzhou of south China. Based on the measured f(RH), the hygroscopicity parameter (κ) of bulk aerosols (κ-f(RH)) exhibits a logarithmic increase with increasing RH until RH reaches 69 %. Beyond this threshold, κ-f(RH) increases very slowly with further increase of RH, reaching 0.32 ± 0.04 during the dry season and 0.31 ± 0.05 during the wet season. The κ of WSOM (κ-WSOM) was further estimated to be 0.22 ± 0.03 and 0.13 ± 0.04 in the dry and wet seasons, respectively, when RH > 69 %. WSOM significantly affects κ-f(RH) by retarding the deliquescence process of aerosols and altering the mass ratio of water-soluble inorganic salts (WSIS) to WSOM within the size range of 0.4–0.9 μm, especially under low RH conditions (<60 %). The κ-f(RH) under low RH conditions was revised based on the logarithmic regression equation between RH and the ratio of measured κ-f(RH) to estimated κ-f(RH>69%). f(RH) of WSIS and WSOM were then corrected using the revised κ-f(RH) under low RH conditions, which showed 22–31 % lower values than those produced by the IMPROVE formulas.

Establishment of a Model and System for Secondary Fertilization of Nutrient Solution and Residual Liquid

At present, the nutrient solution of soilless culture is mostly configured by simply using the standard fertilizer formula, lacking the precise matching technology of nutrient solutions based on nutrient elements. It is unable to change the formula configuration according to vegetable types, different growth stages and growth needs, especially in the secondary fertilizer reuse of nutrient solution reflux. In order to make precise secondary fertilization, a model and system for secondary fertilization of nutrient solution residual liquid were established in this paper. It can be used for secondary fertilization based on nutrient ions and reused after the sterilization of the residual liquid. A nutrient solution fertilizer system based on nutrient elements was designed. The nutrient solution fertilizer system based on the online detection of ions was determined with different element compounds as the fertilizer unit. Combined with the existing hydroponic water-soluble inorganic salts, the ion concentration and its proportioning quantitative model of the nutrient solution recovery solution were established. The experimental verification and result analysis of the fertilizer model were carried out to test the accuracy and practicability of the established model. The ion concentration error obtained from the mathematical model was established as 0.0093–0.5294 mg·L−1.The precise proportioning technology of nutrient solution based on nutrient elements can realize the precise and intelligent proportioning of nutrient elements in the nutrient solution of crops and can also make full use of the nutrient solution. It also improves the efficiency of greenhouse cultivation.

Sources apportionment of water-soluble inorganic salts in CPM from coal-fired power plants with different emission control technologies

Different control technologies to reduce emissions of sulfur oxides and nitrogen oxides from coal-fired boilers have been adopted globally, leading to significant reductions in these gas emissions, especially over the past several years in China. Comparatively, little attention has been paid to the potential effects of these control technologies on particulate matter (PM) emissions, especially condensable particulate matter (CPM), which is harmful to the atmosphere and human health. In this study, we measured filterable and condensable PM emissions in five coal-fired commercial-scale boilers installed with SNCR or SCR for NOx control and wet, semidry, or dry flue gas desulfurization (FGD) for SO2 emission controls. Water-soluble ionic components in PM were analyzed. The experimental results show that the CPM accounts for 55.9% to 95.1% of total particulate matter (TPM) and is composed primarily of water-soluble SO42- and NH4+, with (NH4)2SO4 being the dominant CPM aerosols. Experimental results also reveal that the flue gas emission control technology significantly affects CPM emission from coal-fired boilers. Since the production of (NH4)2SO4-rich CPM results from the use of ammonia solution for NOx reduction, boilers emit more CPM with SNCR than with SCR because the former operates with a higher ammonia/NOx ratio than the latter. Additionally, the CPM emission is related to the FGD technology installed. Boilers installed with wet FGD emit the lowest CPM, followed by semidry and dry FGDs, because of their decreased capabilities of dissolving and absorbing water-soluble components.

Experimental study on transformation of alkali and alkaline earth metals during biomass gasification

To gain an in-depth understanding of AAEMs (alkali and alkaline earth metals) transformation during biomass gasification, a fixed-bed reactor is built to simulate the CO2 gasification at 500–900 °C. The influences of biomass species, gasification temperature, and particle size are examined. The results show that the AAEMs release follow a sequence of candlenut wood > wheat straw > corn stalk. The alkali metals mainly appear as water-soluble inorganic salts and the contents are more than 80%. K mainly occurs as KCl and KClO4. At higher temperatures, K could combine with Al and Si to form K(AlSi3)O8. For candlenut wood, a bigger particle size is beneficial to the transformation of water-soluble K to organic K. For candlenut wood with centimeter-scale, K mainly occurs as organic K in the biochar during 600–700 °C. When the gasification is carried out at 700 °C, K concentrates at the center and its content is even higher than that on the outer surface. While for biochar samples obtained from gasification at 600 and 900 °C, the K content at the center is lower than that on the outer surface due to the continuous outward transformation of K from the central biochar.

Chang impact analysis of level 3 COVID-19 alert on air pollution indicators using artificial neural network

In this study, mean monthly and diurnal variations in fine particulate matters (PM2.5), nitrate, sulfate, and gaseous precursors were investigated during the Level 3 COVID-19 alert from May 19 to July 27 in 2021. For comparison, the historical data during the identical period in 2019 and 2020 were also provided to determine the effect of the Level 3 COVID-19 alert on aerosols and gaseous pollutants concentrations in Taichung City. A machine learning model using the artificial neural network technique coupled with a kinetic model was applied to predict NOx, O3, nitrate (NO3−), and sulfate (SO42−) to investigate potential emission sources and chemical reaction mechanism. D during the Level 3 COVID-19 alert, a decrease in NOx concentration due to a decrease in traffic flow under the NOx-saturated regime was observed to enhance the secondary NO3− and O3 formation. The present models were shown to predict 80.1, 77.0, 72.6, and 67.2% concentrations of NOx, O3, NO3−, and SO42−, respectively, which could help decision-makers for pollutant emissions reduction policies development and air pollution control strategies. It is recommended that more long-term datasets, including water soluble inorganic salts (WIS), precursors including OH radicals, NH3, HNO3, and H2SO4, be provided by regulatory air quality monitoring stations to further improve the prediction model accuracy.

Sources Apportionment of Water-Soluble Inorganic Salts in Cpm from Coal-Fired Power Plants with Different Emission Control Technologies

Sources Apportionment of Water-Soluble Inorganic Salts in Cpm from Coal-Fired Power Plants with Different Emission Control Technologies

A machine learning model for predicting PM2.5 and nitrate concentrations based on long-term water-soluble inorganic salts datasets at a road site station

In this study, long-term variations in the concentrations of PM2.5, water-soluble inorganic salts (WIS), and gaseous precursors measured by a roadside air quality monitoring station were investigated from 2017 to February 2021 to examine the formation mechanism of secondary inorganic PM2.5. A new machine learning model using WIS data as input variables was further developed to predict PM2.5 and nitrate concentrations for source tracing and effective control strategy development. The results showed that a reduction in the NOx concentration under VOC-limited O3 formation regime could offset the consumption of OH and O3, causing an increase in secondary NO3− and PM2.5 formation during fall and winter seasons. A good agreement was obtained between the predicted and measured PM2.5 values, with R2, root mean square error (RMSE), and mean absolute error (MAE) values of 0.81, 6.81 μg/m3, and 5.10 μg/m3, respectively. The nitrate ([NO3−]) prediction model could predict ∼59% of the atmospheric nitrate concentration. The sensitivity analysis of the input variables in the present model further revealed that NO3− and VOC were two important pollutants dominating the variation trend of PM2.5. It is recommended that decision makers should focus more on the reduction of VOC and O3 to reduce secondary PM2.5 formation during winter in central Taiwan. Real-time measurements of the chemical composition of PM2.5, taken as the regulatory air quality monitoring items are needed in the future.

Characterization of temporal PM2.5, nitrate, and sulfate using deep learning techniques

Water-soluble inorganic salts (WIS) contribute a large fraction of PM2.5, which are responsible for the adverse effects on human health and environment. It is important to investigate the long-term variation trend of PM2.5 and WIS for exposure assessment and effective abatement strategies development. In this study, a multi-step ahead artificial neural network (MSA-ANN) and a long short-term memory fully connected (LSTM-FC) model for PM2.5, nitrate (NO3−), and sulfate (SO42−) prediction were developed to provide high temporal resolution datasets. Results show that the kinetic formation rate of HNO3 and HSO3− used as input variables can improve the accuracy of the present model for PM2.5, NO3−, and SO42− prediction. The MSA-ANN is able to predict 80–83%, 93%, and 91% of PM2.5, NO3−, and SO42−, respectively, with t+1 prediction horizon. With increasing prediction horizon to t+4 and t+8, the present model still can track the temporal variation of PM2.5, NO3−, and SO42− very well and capture the peak values during a severe pollution event. The proposed method is applicable to predict regional temporal variation trend of PM2.5, NO3−, and SO42− and fill the data gap in area with limited WIS measurement.

Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing.

The 20th and 21st century oil paintings are presenting a range of challenging conservation problems that can be distinctly different from those noted in paintings from previous centuries. These include the formation of vulnerable surface "skins" of medium and exudates on paint surfaces, efflorescence, unpredictable water and solvent sensitivity, and incidence of paint dripping which can occur within a few years after the paintings were completed. Physicochemical studies of modern oil paints and paintings in recent years have identified a range of possible causal factors for the noted sensitivity of painting surfaces to water and protic solvents, including the formation of water-soluble inorganic salts and/or the accumulation of diacids at the paint surface, which are oxidation products of the oil binder. Other studies have investigated the relationship between water sensitivity and the degree of hydrolysis of the binder, the proportions of free fatty and dicarboxylic acids formed, as well as the relative content of free metal soaps. Thus far, data indicate that the qualitative and quantitative composition of the nonpolymerized fractions of the oil binder cannot be solely or directly related to the solvent sensitivity of the paint film. Conclusions therefore indicate that the polymeric network, formed upon the curing of the oil, plays a fundamental role, suggesting that water sensitivity, at least in some cases, may be related to the poor development and/or polar nature of the formed polymeric network rather than the composition of the nonpolymerized fractions. Poorly developed polymeric networks, in combination with the migration of polar fractions, i.e., dicarboxylic and hydroxylated fatty acids toward the paint surface, can be related to other degradation phenomena, including the separation and migration of the paint binder which can lead to the presence of observable skins of medium as well as the more alarming phenomenon of liquefying or dripping oil paints. It is thus crucial to understand the molecular composition of these paints and their physicochemical behavior to aid the further development of appropriate conservation and preservation strategies, as the risks currently associated with surface cleaning treatments and other conservation procedures can be unacceptably high. This Account reviews the relationships between the degradation phenomena associated with modern oil paintings and the chemical composition of the oil binder and proposes a molecular model for the development of water sensitivity and other noted degradation phenomena. It is suggested that water sensitivity (and possibly other degradation phenomena) is a consequence of processes that take place upon curing, and in particular to the rate of formation and decomposition of alkoxyl and peroxyl radicals. These reactions are strongly dependent on the type of oil present, the ambient environmental conditions, and the chemical and physical nature of the pigments and additives present in the paint formulation. When the curing environment is oxidizing, the chemistry of peroxyl radicals dominates the reaction pathways, and oxidative decomposition of the paint film overwhelms cross-linking reactions.

Seasonal Variation and Source Analysis of Water-soluble Inorganic Salts in PM2.5 in the Southern Suburbs of Beijing

In order to study the variation of water-soluble inorganic ions in the four suburbs of Beijing using the atmospheric fine particulate matter rapid trapping system and chemical composition analysis system (RCFP-IC), we carried out measurements for nine water-soluble inorganic ions (Cl-, NO2-, NO3-, SO42-, Na+, NH4+, K+, Mg2+, Ca2+) in PM2.5 with continuous on-line observations for one year in Beijing's southern suburbs in 2016. The transport process of pollutants and the potential sources of pollutants were evaluated by combining a trajectory clustering method and potential source contribution factor analysis method (PSCF). During the observation period, the total concentration of the nine water-soluble inorganic ions was 38.6 μg ·m-3, and results showed that the concentration in winter and spring was high and in summer and autumn was low. The order of the concentration from high to low was SO42- > NO3- > NH4+ > Ca2+ > NO2- > Cl- > Na+ > K+ > Mg2+. In winter, the SO42-, NO3- and NH4+ accounted for 75.7% of the total measured water-soluble ions, followed by 72.8% in spring and 60.2% in summer. With an increase in air pollution, the concentrations of SO42-, NO3-, and NH4+ increased significantly, indicating that SO42-, NO3-, and NH4+ were closely related to the deterioration of air quality. SO42- was dominant in the formation of secondary ions compared to NO3- and NH4+; and SO42-, NO3-, and NH4+ had significant diurnal variations. The diurnal variation of the SO42- statistic (hours) was bimodal, and the peak values were at about 10:00 and 18:00. The diurnal variation of NO3- and NH4+ had single peaks, with the peak appearing at 10:00. The trend of the diurnal variation for these two ions was similar. Finally, the sources of pollution in the southern suburbs of Beijing mainly included secondary sources, coal-fired sources, and mixed sources of dust and dust. The main potential source of pollution in the southern suburbs was in the southeastern part of the observation site, while the northeastern airflow was favorable for the diffusion and dilution of pollutants.

Uneven distribution of inorganic pollutants in marine air originating from ocean-going ships

The distribution of mass, water-soluble inorganic salts and mineral elements of size-segregated aerosols (PM1, PM2.5-1 and PM10-2.5), precursor gaseous pollutants, black carbon, and nanoparticles (10–300 nm size range) at the Southern Bight of the North Sea has been studied. The concentrations of air pollutants peaked over shipping lanes, open-water anchorage areas and frequently navigated waters, due to the presence of mobile emission sources. A considerable decrease in air pollutant levels was seen when diverting from these marine areas towards remote or coastal banks. These findings showed the rapid dispersion of pollutants in the marine air. The nano-aerosol count, originating from ocean-going ships, peaked at lower average aerodynamic diameters (e.g., ≈28 nm) than those, observed from low-displacement vessels (45–50 nm, e.g., for fishing boats). The average diameter of nano-PM depended also on weather conditions, e.g., it was higher (≈50 nm) in air of higher humidity.

Novel polystyrene sulfonate–silica microspheres as a carrier of a water soluble inorganic salt (KCl) for its sustained release, via a dual-release mechanism

Polystyrene sulfonate and silica microspheres with potassium chloride encapsulated show a dual-release mechanism of K+ in an aqueous environment.

Thermal and spectroscopic analysis of organic matter degradation and humification during composting of pig slurry in different scenarios.

In this work, different analytical techniques (thermal analysis, (13)C cross-polarization magic angle spinning (CPMAS) NMR and Fourier transform infrared (FT-IR) spectroscopy) have been used to study the organic matter changes during the co-composting of pig slurry with cotton gin waste. To ensure the validity of the findings, the composting process was developed in different scenarios: under experimental pilot plant conditions, using the static pile system, and under real conditions on a pig farm, using the turning pile system. Also, the thermal stability index (R1) was determined before and after an extraction with water, to evaluate the effect of eliminating water-soluble inorganic salts on the thermal analysis. The results of the thermal methods showed the degradation of the most labile organic matter during composting; R1 increased during composting in all piles, without any influence of the presence of water-soluble inorganic ions in the sample. The NMR showed a decrease in the abundance of the carbohydrate molecules and an increase in the aliphatic materials during composting, due to a concentration effect. Also, FT-IR spectroscopy was a useful technique to study the trends of polysaccharides and nitrate, as indicators of organic matter transformations during composting.

Microwave-assisted nickel and vanadium removal from crude oil

Most crude oils contain traces of metal complexes, among which vanadium (V) and nickel (Ni) compounds are the most harmful poisons to the catalysts of fluid catalytic cracking (FCC) and hydrogenation units. These metals are proven to be extremely hard to remove, since they exist in crude oil as stable oil-soluble complexes. The microwave technology provides a new way for Ni/V removal, their removal efficiency using chemical reagents and the mechanism of microwave-assisted demetallization were studied in this paper. It was concluded that the demetallization efficiency can be highly enhanced under microwave irradiation. There is no specific structural selectivity for vanadium porphyrins during microwave treatment process. The demetallization agent — methanesulfonic acid, containing a sulfonyl acid group was found to react with VO2+ and Ni2+. Ni and V were removed from porphyrin ring without destroying the ring structure, corresponding water soluble inorganic salts were formed, thus can be successfully separated from crude oil by washing or desalting process.

Rapid Synthesis of Water-soluble NiCl2 Nanorods via Recrystallization for Super Capacitors Applications

Highly uniform NiCl2 nanorods were synthesized successfully via recrystallization and employed as electrode materials for super capacitors applications. The water-soluble Ni/NiCl2 electrode proves to show typical pseudocapacitive characteristics and delivers a very high specific capacitance of 1182.7 F g-1 at 2 A g-1. The charge storage and conversion process initiates from the chemically combination of Ni2+ and OH-, and maintains a reversible redox reaction of Ni(II) ↔ Ni(III) on the electrode. It opens a new insight into the fabrication of multifarious water-soluble inorganic salts for super capacitors applications using the ionic electro negativity parameter as the theoretical guideline.

Atmospheric dry plus wet deposition and wet-only deposition of dicarboxylic acids and inorganic compounds in a coastal suburban environment

This study investigated the chemical properties and composition sources of dicarboxylic organic acids and inorganic salts in dry plus wet deposition (DWD) and wet-only deposition at a coastal suburban area in southern Taiwan in 2008. DWD is the accumulation of dry deposition and wet deposition from the beginning of each new rain event, while wet-only deposition is the wet deposition from the beginning of each new rain event only. A total of 60 samples were collected during the period of study. The wet-only deposition samples were slightly more acidic (pH 5.01–5.50) than the DWD samples (pH 5.51–6.00). The total volume-weighted mean (VWM) equivalent ionic concentration of 784.3 ± 431.1 μeq L−1 in DWD was higher than that of 682.2 ± 392.4 μeq L−1 in wet-only deposition. In both types of deposition the major cation species were Ca2+, Na+ and NH4+, and the major anion species were HCO3−, Cl− and non-sea salt (nss) nss-SO42−. Total dicarboxylic acids contributed only 0.60% and 0.45% of the total ionic equivalent concentration in DWD and wet-only deposition, respectively, and oxalic and malonic acids were the major dicarboxylic acid species. DWD to wet-only deposition species concentration ratios (DWD/W ratios) were always higher than 1.0. DWD contained more water-soluble inorganic salts and dicarboxylic acids than wet-only deposition, with DWD/W ratios of the dust-bound species K+, Mg2+ and Ca2+ as large as 1.6–1.8 and those from photochemical species nss-SO42− and NH4+ of 1.36 and 1.29, respectively. These ratios show that the dry deposition flux of dust is greater than that of photochemical particles. In addition, the 1.81 ratio for oxalic acid shows that oxalic acid is easier to remove from the atmosphere via dry deposition than malonic and succinic acids. Probable deposition composition sources for both DWD and wet-only deposition, investigated using principal component analysis, were marine spray, photochemical inorganic products, and terrestrial origin and photochemical organic products. As the study site is close to the coast, marine spray deposits as dry deposition, and the anthropogenic dicarboxylic acids deposit together with resuspended crustal materials.

Water-soluble inorganic salt with ultrahigh specific capacitance: Ce(NO3)3 can be designed as excellent pseudocapacitor electrode

The improvement of the performance of pseudocapacitors has previously been limited to the synthesis of electrode materials with different structures and sizes. The water-soluble inorganic salts have not been explored their pseudocapacitance in aqueous electrolyte. Here, for the first time, we demonstrated that the ultrahigh specific capacitance of 2060 F/g can be obtained by the direct use of commercial Ce(NO3)3 as electrode materials in KOH electrolyte without any additional processing. As main capacitive charge-storage ions, Ce3+/Ce4+, which undergo chemical reactions and electrochemical reactions, can deliver high practical specific capacitance that is close to its theoretical value. The results challenge the view that the synthesis of advanced electrode materials with specific structures is the important step to increase the specific capacitance of inorganic pseudocapacitors.

Softening Effect of Bentonite and Redeposition of Solid Impurities on Washed Cotton Fabric

Abstract The aim of this work is to propose a contribution to obtain an improvement in the redeposition of solid impurities on cotton fabric during washing with ecological surfactants and also the enhancement of their smoothness. For that purpose, sodium bentonite was added to the detergent formulations to produce a smoothing effect while washing, to obtain what is known as “softergent”. Thus, smoothing with this product, the necessity of adding softener in the last rinse during washing is eliminated, with the savings of softeners and time and more ecological waste water. This was possible given the excellent compatibility of the bentonite with all the components of the detergent. As a water-soluble inorganic salt, bentonite is environmentally friendly. The surfactants used in the detergent formulations were the anionic sodium dodecylbenzene sulfonate (SDBS) and the two non-ionic surfactants, APG and AE with 7 m. EO, which were used separately and in mixtures of different proportions of anionic and non-ionic surfactants. The sodium bentonite (composed mainly of silicates and aluminates) was used with two types of particle size, without surface treatment and with and without ammoniumsilicone softener treatment to show the effect on their behaviour. The redeposition behaviour on the cotton fabric and the smoothness produced after washing with bentonite microparticles in the detergent formulation, depending on use of the surfactants alone or in the different proportions of anionic : non-ionic surfactants were measured. The smoothness of cotton fabrics produced by the bentonite microparticles after washing was evaluated by hand. A relationship between handle and inorganic ash contents was established. Also, the electrical double layer of the bentonites was measured in the presence of the surfactants tested.