The impact of drilling mud components on the filtration activity and survival of bivalve molluscs was investigated by exposing them to suspensions of ‘standard’ barite, finely milled barite, ilmenite and bentonite in sea water. Introduction of the components stimulated filtration activity in all four bivalves. In addition, the introduction of standard barite and ilmenite both had lethal effects, with none of the bivalves surviving the full duration of the experiments. In-vivo observations of the gill surfaces provided direct evidence of physical damage caused by the administration of barite and ilmenite. A marked difference between filtration activity and survival of animals dosed with ‘standard’ barite and ‘fine’ barite suggests that the observed effects were primarily caused by physical interference with gill function. The results also suggest that the use of fine barite in offshore drilling may provide a more favourable environmental impact profile than the use of ilmenite.

A test program was conducted at laboratory and pilot scale to assess the ability of clays used in drilling mud (calcite, bentonite and barite) to create oil-mineral aggregates and disperse crude oil under arctic conditions. Laboratory tests were performed in order to determine the most efficient conditions (type of clay, MOR (Mineral/Oil Ratio), mixing energy) for OMA (Oil Mineral Aggregate) formation. The dispersion rates of four crude oils were assessed at two salinities. Dispersion was characterized in terms of oil concentration in the water column and median OMA size. Calcite appeared to be the best candidate at a MOR of 2:5. High mixing energy was required to initiate OMA formation and low energy was then necessary to prevent the OMAs from resurfacing. Oil dispersion using Corexit 9500 was compared with oil dispersion using mineral fines.

Elevated suspended sediment concentrations (SSCs) often impact coral fertilisation success, but sediment composition can influence effect thresholds, which is problematic for accurately predicting risk. Here, we derived concentration–response thresholds and cause-effect pathways for SSCs comprising a range of realistic mineral and organic compositions on coral fertilisation success. Effect concentration thresholds (EC10: 10% fertilisation inhibition) varied markedly, with fertilisation highly sensitive to inshore organic-clay rich sediments and bentonite clay at <5 mg L−1. Mineral clays and organic matter within these sediments likely promoted flocculation of the coral sperm, which in turn reduced fertilisation. In contrast, sediments lacking these properties bound less sperm, leading to higher SSC thresholds for coral fertilisation (EC10 > 40 mg L−1). The effect thresholds for relevant sediment types were combined with in situ turbidity data from locations near dredging operations to assess the risks posed by dredging to coral fertilisation at these locations.

Aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) are highly toxic mycotoxin metabolites that are found as food pollutants, posing health risks to humans and animals. The objective of the current study is to establish a sensitive, reliable method for determining AFM₁ and OTA using high-performance liquid chromatography (HPLC) and attempting to assess the efficacy of bentonite, date pit, and chitosan nanoparticles for AFM₁ and OTA detoxification from contaminated milk. As revealed, AFM₁ was found in 65.7% of analyzed samples ranging from 4.5 to 502 ng/L, while 25.7% of examined samples contained OTA ranging from 1.45 to 301 ng/L. Furthermore, for AFM₁ and OTA. The advanced procedure was thoroughly validated by evaluating linearity (R² > 0.999), LOD (0.9615 and 0.654 ng/L), and LOQ (2.8846 and 1.963 ng/L), recovery (93–95% and 87–91%), as well as precision (≤ 1%RSD). The experimental data revealed a higher removal efficiency of bentonite and date pit than chitosan nanoparticles in the case of AFM₁ (68%, 56%, and 12%) and OTA (64%, 52%, and 10%), respectively with slight change in nutritional milk components like fat, protein, and lactose. Eventually, it is concluded that bentonite and date pit can be considered efficient adsorbing agents to extract AFM₁ and OTA from contaminated milk.

The leakage of chemical compounds in landfill leachate led to serious environment pollution, especially, the compounds termed endocrine disruptors such as bisphenol A (BPA). It is very important to study the adsorption behavior of endocrine disruptors in modified soil for predicting and evaluating the potential harm of endocrine disruptors to the soil. Bentonite-amended Chinese loess mixtures, with various proportions of bentonite, were used for the removal of BPA from an aqueous solution. A batch test was used to investigate the adsorption properties of bisphenol A on bentonite and Chinese loess mixtures. The influences of bentonite proportion, temperature, reaction time, pH, and soil-water ratios on the adsorption process were considered. The Fourier transform infrared spectra (FTIR) was used to clarify the change of functional groups before and after the adsorption of BPA on soil. The adsorption mechanism of BPA on soil was discussed preliminary. The results show that the addition of bentonite to the loess can improve the adsorption rate of BPA. The adsorption of BPA was mainly a spontaneous, exothermic, entropy decreasing physical adsorption process. The interaction between bentonite content and reaction concentration had a beneficial effect on BPA adsorption. The linear relationship between bentonite content and adsorption capacity was obtained. The results indicate that bentonite amended loess can provide a good liner for BPA.

This study evaluated the adsorption of the herbicide 2,4-D in a fixed bed adsorption system using organophilic clay obtained from the chemical modification of sodium bentonite commercialized as Fluidgel®. For this purpose, the operating conditions of the adsorption column were evaluated, such as flow rate (1, 3, and 5 mL min⁻¹) and initial pesticide concentration (10, 20, and 30 mg L⁻¹), and the operational parameters of the bed were calculated for each experimental condition. A flow rate of 1 mL min⁻¹ and initial concentration of 10 mg L⁻¹ were the operational conditions that provided the best operational results for the column, obtaining a rupture time of 1700 min, hMZT of 3.8 cm, and useful and total removal percentages of 96 and 76.6%, respectively. The mathematical models of Thomas and Yoon & Nelson were the most predictive to the breakthrough curves raised, obtaining high correlation coefficient values (R

The present study evaluates the performance of an indigenously developed ceramic ultrafiltration (UF) membrane in a lab-scale membrane bioreactor (MBR) process to treat real tannery effluent with varying organic loading (1500–6000 mg/L). UF membrane was prepared by the coating of bentonite clay on tubular clay-alumina macroporous support. The membrane surface was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, BET adsorption–desorption, contact angle measurement, and atomic force microscopy. In the side-stream MBR process, sewage sludge from a local sewage treatment plant was used as an activated sludge source with a constant sludge retention time of 30 days. Membrane filtration was performed in cross-flow mode using a single-channel membrane module. Artificial neural network (ANN) modeling tool was used to analyze the influence of various independent input variables, namely, the hydraulic retention time (4–10 h), mixed liquor suspended solid (MLSS) concentration (2–8 g/L), and influent COD concentration (1500–6000 mg/L) on COD removal (%) with feed-forward backpropagation method. Membrane study was done at a transmembrane pressure of 4.3 bar and feed flow rate of 7.5 L/min to observe the flux declination and fouling of the UF membrane with time. Average COD and BOD concentrations obtained in the treated effluent were 147.56 and 31 mg/L, respectively, and chromium concentration was < 0.1 mg/L; thus, treated effluent quality was found to be suitable for industrial recycling purposes apart from the safe environmental discharge. An in-depth study was undertaken to understand the removal mechanism in the MBR process, nature and extent of membrane fouling, changes in the morphology of the UF membrane, surface wettability, and surface topology by detailed surface characterization of the membrane pre- and post-filtration.

At present, plastic concrete is widely used in anti-seepage engineering, and its strength and hydraulic conductivity are important indexes of plastic concrete cutoff walls. The pondus hydrogenii (pH) and electrical conductivity (EC) have an important effect on the strength and hydraulic conductivity of plastic concrete cutoff walls. However, it is not clear why the pH and EC are related to the strength and permeability of these walls. For this reason, plastic concrete composed of sand, cement, water, and bentonite was taken as the research object to study the influence of different mix ratios and curing ages on the unconfined compressive strength and permeability of plastic concrete. The pH and EC of the corresponding mix ratio and curing age were measured. The effects of the pH and EC on the strength and permeability of plastic concrete were studied, and the internal reason was explored from the product type and hydration reaction degree of plastic concrete. Furthermore, the quantitative relationship between pH and EC and the strength and hydraulic conductivity of plastic concrete was established. With increasing cement content, the strength, pH, and EC of plastic concrete increase continuously, while the hydraulic conductivity decreases. With increasing curing age, the strength increases, the hydraulic conductivity decreases, and both the pH and EC show a trend of first increasing and then decreasing. The pH value and electrical conductivity can reflect the product type and hydration reaction degree of plastic concrete, further affecting its strength and hydraulic conductivity. Under different dosage and curing age conditions, the pH showed three stages, namely, 11.7–12.27, 12.27–2.5, and 12.5–12.75, and there is a good power functional relationship among the EC and strength and hydraulic conductivity at each stage.

Four artificial soils (AS) were prepared based on a mixture of humus, bentonite, kaolinite, and polyvinyl chloride (PVC), as inert matter, in the following proportion: 0%, 12.44%, 37.50%, 78.55% of humus, 10.5% of bentonite, 10.5% of kaolinite, and 78.92%, 66.26%, and 41.46% of PVC. The AS were prepared with variable content of organic matter (OM) in order to evaluate the retention of lead (II) due solely to the content of OM. The results indicated that retention capacity of Pb⁺² increases (19.74 mg/g, 20.89 mg/g, 61.61 mg/g, and 79.48 mg/g) as OM increases (0%, 1%, 5%, and 10%); however, this retention is not proportional to the OM increment. An increase of background solution concentration of 0.01 M to 0.1 M resulted in a 50% decrease in the lead retention capacity. The fitting of lead adsorption was performed by the regression coefficient (R²). All R² of the Langmuir model fit successfully to all types of AS (0.973 for 10-OM, 0.9845 for 5-OM, 0.999 for 1-OM, 0.994 for 0-OM). The adsorption kinetics also fits well to the pseudo-second-order model (R²₁₀₋OM = 0.989, R²₅₋OM = 0.999, R²₁₋OM = 0.999, and R²₀₋OM = 0.999). The thermodynamic values of the Gibbs free energy (ΔG⁰₁₀₋OM = − 10.62, ΔG⁰₅₋OM = − 11.50, ΔG⁰₁₋OM = − 14.23, and ΔG⁰₀₋OM = − 17.06) indicated that it was a spontaneous process, and the energy of the process suggests a retention mechanism by ion exchange. A soil with high content of OM does not guarantee high retention of lead, even more so when the adsorption mechanism is given by ion exchange.

In this research, the sorption behavior (kinetic, isotherm, and thermodynamic modeling) of heavy metals (Cu (II) and Fe (II)) and pigments (carotenoid and chlorophyll) onto activated bentonite clay was investigated for soybean oil under industrial (IBM) and ultrasonic bleaching method (UBM). A nonlinear fitting approach was used to determine the best-fit isotherm and kinetic models by two statistical criteria including the coefficient of determination (R²) and chi-square (χ²). The adsorption of metal ions and pigments onto activated bentonite clay under UBM was quite well by the pseudo-first-order model. In both bleaching methods, the equilibrium adsorption data follows the Toth isotherm model, presenting the sorption occurrence tends to be on a heterogeneous surface. The results indicated that the adsorption thermodynamics was endothermic in nature and the process was spontaneous between 35 and 65 °C.