Waste Bentonite Research Articles

Colloidal Properties of Polymer Amended Cyprus Bentonite for Water-Based Drilling Fluid Applications

In this work, we investigate the capability of a waste bentonite from the Polycanthos quarry in Cyprus, as a low-density solid additive to create colloids that are used in water-based drilling fluid systems (WBF) in drilling operations. Repurposing waste bentonite aligns with environmental sustainability and when properly processed can serve as a cost-effective solution to achieve the desired colloidal properties for WBF. Samples were obtained from waste stockpiles and were mechanically processed to a size < 63 μm. The material was activated with soda ash via three different methods investigating optimum soda ash percentage and curing time. Standard tests were performed for the rheological behavior and filtration properties and the results indicated that the quality of the activated clay dispersions improved slightly but the desired colloidal properties were not obtained. This can be attributed to the K+-rich clay and non-clay impurities that are inherent in the material so further amendment with xanthan gum polymer was conducted, at various concentrations. Results of this work show that with minor polymer addition, the material under investigation reaches the desired colloidal properties and qualifies according to API standards for WBF. Exploiting local waste clay material in WBF application leads to the development and sustainability of local resources thus contributing to the circular economy principle.

Thermal Recycling of Bentonite Waste as a Novel and a Low-Cost Adsorbent ‎for Heavy Metals Removal

Thermal Recycling of Bentonite Waste as a Novel and a Low-Cost Adsorbent ‎for Heavy Metals Removal

A feasibility study of kitchen waste and waste bentonite as adsorbent for P-containing wastewater treatment: performance and mechanism

A feasibility study of kitchen waste and waste bentonite as adsorbent for P-containing wastewater treatment: performance and mechanism

Production of sorptive granules from incinerated sewage sludge ash and upcycling in cement mortar

This paper describes a method to produce sorptive granules solely from solid waste. The produced granules can remove multi-toxic heavy metal(loid)s from wastewaters and be upcycled as lightweight aggregates in cement mortars. Specifically, kilogram-scale production of millimeter-sized granules was obtained via the thermal treatment of green bodies prepared from phosphorus-stripped incinerated sewage sludge ash (ISSA), peanut shell and waste bentonite at a mass ratio of 1:1:2 at 1050 °C under a N2 atmosphere. The synthesized granules with good mechanical strength (4.9 MPa) exhibited excellent adsorption capacities towards As(V), Cr(VI), Cu(II) and Pb(II) at respectively 14.11, 5.79, 14.12 and 23.52 mg/g at an initial solution pH of 3.0 via mechanisms including redox reactions, complexation, (co)precipitation, and cation exchange. Moreover, the potentially hazardous spent granules could be environmental safely reused as a partial river sand replacement in cement mortars based on the Toxicity Characteristics Leaching Procedure.

Green Extraction of Polyphenols from Waste Bentonite to Produce Functional Antioxidant Excipients for Cosmetic and Pharmaceutical Purposes: A Waste-to-Market Approach.

In an ever-growing perspective of circular economy, the development of conscious, sustainable and environmental-friendly strategies to recycle the waste products is the key point. The scope of this work was to validate the waste bentonite from the grape processing industries as a precious matrix to extract polyphenols by applying a waste-to-market approach aimed at producing novel functional excipients. The waste bentonite was recovered after the fining process and opportunely pre-treated. Subsequently, both the freeze dried and the so-called "wet" bentonites were subjected to maceration. PEG200 and Propylene Glycol were selected as solvents due to their ability to dissolve polyphenols and their wide use in the cosmetic/pharmaceutical field. The extracts were evaluated in terms of yield, density, pH after water-dilution, total phenolic (Folin-Ciocalteu) and protein (Bradford) contents, antioxidant power (DPPH), amount of some representative polyphenols (HPLC-DAD), cytocompatibility and stability. Both solvents validated the bentonite as a valuable source of polyphenols and led to colored fluids characterized by an acidic pH after water-dilution. The best extract was obtained from the wet bentonite with PEG200 and highlighted the highest phenolic content and consequently the strongest antioxidant activity. Additionally, it displayed proliferative properties and resulted almost stable over time. Hence, it might be directly used as polyphenols-enriched functional novel raw material for cosmetic and pharmaceutics purposes.

Incorporation of Bentonite Mining Waste in Ceramic Formulations for the Manufacturing of Porcelain Stoneware

Mining processes produce a massive amount of waste which, if not treated properly, can cause significant environmental and social impacts. Recently, some studies have focused on the use of mining waste as an alternative raw material. This work developed new sustainable ceramic formulations based on bentonite mining waste (BMW) for applications in porcelain stoneware. The BMW was incorporated into the ceramic masses in different percentages (0, 2.5, 5, 10, 15, 20, 25, and 40 wt.%), in partial replacement to feldspar and total to quartz. X-ray diffraction (XRD), differential thermal calorimetry (DTA), and thermogravimetry analysis (TGA) techniques were used to characterize bentonite waste. Samples (50 mm × 20 mm × 5 mm) were obtained by uniaxial pressing. Such samples were dried and sintered at 1150, 1200, and 1250 °C. The physical–mechanical properties (apparent porosity, water absorption, linear shrinkage, apparent density, and flexural strength) were evaluated for sintered samples. The phases formed after sintering treatments were characterized by XDR and scanning electron microscopy (SEM). The BMW presented a mineralogical composition suitable for use as ceramic raw material. In summary, our results presented that the new sustainable ceramic formulations sintered at 1250 °C have the potential for use in stoneware and porcelain stoneware.

Novel recycling of incinerated sewage sludge ash (ISSA) and waste bentonite as ceramsite for Pb-containing wastewater treatment: Performance and mechanism

With rapid economic growth and urbanisation, the reuse and recycling of solid wastes has become a high priority for the sustainable development of modern cities. In this study, two typical solid wastes, incinerated sewage sludge ash (ISSA) and waste bentonite, were co-valorised to produce granular adsorbents through a simple and energy-saving pelletisation/sintering process. A mixture of ISSA and bentonite at a weight ratio of 3:1 was pelletised and sintered at 700 °C. The resultant ceramsite, with good mechanical strength, could effectively remove Pb(Ⅱ) from aqueous solutions. The adsorption kinetics can be described by the pseudo-first-order (PFO) model. The results indicated that the Pb(Ⅱ) adsorption process was dominated by electrostatic attraction, precipitation, and complexation. The isothermal data exhibited a good correlation with the Freundlich model, indicating that the adsorption process was non-ideal and spontaneous. The maximum adsorption capacity was approximately 21.6 ± 0.35 mg/g at 318 K. After 5 cycles of regeneration, the adsorbent maintained good adsorption performance. Moreover, the removal rate was not greatly affected by ionic strength. These findings demonstrate that the granular adsorbent prepared with ISSA and waste bentonite can be recognised as a promising adsorbent for Pb-containing wastewater treatment.

Carbon mineralization in acidic soils amended with an organo-mineral bentonite waste

Carbon mineralization in acidic soils amended with an organo-mineral bentonite waste

Modification of chemical properties, Cu fractionation and enzymatic activities in an acid vineyard soil amended with winery wastes: A field study

The effects of adding two winery wastes, perlite waste (PW) and bentonite waste (BW), to an acid vineyard soil were assessed using some chemical and biological soil properties in a field study that lasted 18 months. The addition of PW (up to 81 Mg ha−1) had neither significant nor permanent effects on soil characteristics such as the pH, organic matter content or nutrient concentrations, the amounts of copper or zinc, or the electrical conductivity. Moreover, no persistent negative effects were found on the enzymatic activities after PW application. In contrast, soil that was amended with up to 71 Mg BW ha−1 showed increases in its soil pH values, exchangeable potassium and water soluble potassium and phosphorus contents. In addition, it caused significant increases in the electrical conductivity and water-soluble Cu. In addition, the phosphomonoesterase enzymatic activity decreased significantly (up to 28%) in response to the amendment with 71 Mg BW ha−1. These results showed that adding BW and PW to the soil may be a good agronomic practice for recycling these types of wastes. However, in the case of PW, its use as a soil amendment must be performed with caution to control its possible harmful effects.

Time evolution of the general characteristics and Cu retention capacity in an acid soil amended with a bentonite winery waste

The effect of bentonite waste added to a “poor” soil on its general characteristic and copper adsorption capacity was assessed. The soil was amended with different bentonite waste concentrations (0, 10, 20, 40 and 80 Mg ha−1) in laboratory pots, and different times of incubation of samples were tested (one day and one, four and eight months). The addition of bentonite waste increased the pH, organic matter content and phosphorus and potassium concentrations in the soil, being stable for P and K, whereas the organic matter decreased with time. Additionally, the copper sorption capacity of the soil and the energy of the Cu bonds increased with bentonite waste additions. However, the use of this type of waste in soil presented important drawbacks for waste dosages higher than 20 Mg ha−1, such as an excessive increase of the soil pH and an increase of copper in the soil solution.

A Comparative Study on the Physical Properties of Artificial Aggregates Made from Acid Clay and Dredged Soil

Artificial aggregates (AAs) were manufactured from the acid clay (waste bentonite) and dredged soil produced at a thermal power plant by sintering at 600~1200°C for 10min. And those specimens were compared with respect to their bloating ability. The aggregates of acid clay had well-developed black core and uniform macro pores. The specific gravity of the AAs of acid clay increased with sintering temperature at 600~1000°C due to densification, but dramatically decreased at 1100°C, and at this temperature, the AAs showed bloating. The specific gravity and water absorption of the aggregates of dredged soil decreased with sintering temperature at 600~1000°C, indicating that the dredged soil has the ability to enlarge the sintering temperature range, favorable for the mass production process. The specific gravity of the AAs fabricated in this research ranged 0.8~2.0 and the water absorption ranged 4~26%, which was sufficient for various applications, such as functional membranes, light weight construction, smart soil, sound absorption and insulation fields etc..

Long-lasting Effects of Bentonite on Properties of A Sandy Soil Deprived of the Humus Layer

Abstract Bentonite has been recognized as a very good material for the improvement of coarse textured soils. In microplot experiment, of a sandy soil deprived of the humus layer was enriched in 1973 with waste bentonite at the rates of 0, 3, 6 and 12 kg m-2. Until 2002, the microplots were planted with different crops and regularly enriched with mineral and organic fertilizers. Since 2003, the microplots were left barren. In 2009, determinations of several features of the soils (in 5-30, 30-55 and 55-80 cm layers) showed that the historical amendment of the sandy soil with bentonite (especially its highest dose) ensured significantly higher contents of water, organic C, clay, silt and a sand fraction with particle diameter &lt;0.1 mm in 5-30 cm layer. Proportions of non-dispersible clay in the total clay of bentonite soils in the two upper soil layers were significantly lower than those of the control soil. A significant increase in the penetrometer resistance was observed in 40-58 cm layers of the control soil and the soil with 3 kg m-2 bentonite amendment, contrary to the soils with two highest bentonite doses.

Cyprodinil retention on mixtures of soil and solid wastes from wineries. Effects of waste dose and ageing.

In spite of its wide-world economic relevance, wine production generates a huge amount of waste that threatens the environment. A batch experiment was designed to assess the effect of the amendment of an agricultural soil with two winery wastes (perlite and bentonite wastes) in the immobilization of cyprodinil. Waste addition (0, 10, 20, 40, and 80 Mg ha(-1)) and different times of incubation of soil-waste mixtures (1, 30, and 120 days) were tested. The addition of wastes improved the soil's ability to immobilize cyprodinil, which was significantly correlated to total C content in soil-waste mixtures. Longer incubation times decreased the cyprodinil sorption possibly due to the mineralization of organic matter but also as a consequence of the high pH values reached after bentonite waste addition (up to 10.0). Cyprodinil desorption increased as the amount of waste added to soil, and the incubation time increased. The use of these winery wastes contributes to a more sustainable agriculture preventing fungicide mobilization to groundwater.

Assessment of strontium immobilization in cement–bentonite matrices

The feasibility of immobilizing strontium in cement–bentonite matrices was investigated by studying the effect of mineralogical phase development on mechanical and containment performances. Within this context, the chemical composition and physical properties of bentonite were determined. Different cement–bentonite waste matrices were prepared and analyzed using XRD technique to trace the changes in phases during the curing period. The mechanical performance of these matrices was evaluated by measuring the compressive strength throughout their curing period and the containment performance was determined by conducting long-term static leaching test then the experimental results were checked against some regulatory limits. The results indicated that the presence of strontium and bentonite did not lead to formation of new hydrated phases. The mechanical performance of the matrices is acceptable and the enhanced compressive strength was attributed to the progression in the formation of cement hydrated phases and the pozzolanic reaction between bentonite and lime in cement–bentonite matrices. The speciation data and phase structures analysis indicated that Sr2+ containment in cement might be due to Ca substitution in Ettringite structure and cations exchange on Montmorillonite lattice. The mathematical analysis of the long-term leaching results indicated that strontium leaching resulted from a combination of first order reaction and diffusion mechanisms.

Application of XPS method in the research into Ni ion-modified montmorillonite as a SO2 sorbent

A series of montmorillonites with adsorbed nickel ions was prepared through adsorption of nitrates from water solutions; there were four methods adopted. The surface of the sample under modification was investigated with the method of argon adsorption and XPS (X-ray photoelectron spectroscopy). SO2 was investigated on nickel-modified montmorillonites. Nickel cations were adsorbed on the montmorillonite surface as Ni2+ in Ni(OH)2 or NiO. Montmorillonite — after nickel adsorption — adsorbs SO2 physically. An addition of Mont–Ni to hard coal in a ratio 1:500 reduces SO2 emissions in the combustion process by 75–85%. Waste bentonite can be utilized for reducing SO2 emissions after processing.

Quaternary herbicides retention by the amendment of acid soils with a bentonite-based waste from wineries

The agronomic utility of a solid waste, waste bentonite (WB), from wine companies was assessed. In this sense, the natural characteristics of the waste were measured, followed by the monitoring of its effects on the adsorption/desorption behaviour of three quaternary herbicides in acid soils after the addition of increasing levels of waste. This was done with the intention of studying the effect of the added organic matter on their adsorption. The high content in C (294 g kg −1), N (28 g kg −1), P (584 mg kg −1) and K (108 g kg −1) of WB turned it into an appropriate amendment to increase soil fertility, solving at the same time its disposal. WB also reduced the potential Cu phytotoxicity due to a change in Cu distribution towards less soluble fractions. The adsorption of the herbicides paraquat, diquat and difenzoquat by acid soils amended with different ratios of WB was measured. In all cases, Langmuir equation was fitted to the data. Paraquat (PQ) and diquat (DQ) were adsorbed and retained more strongly than difenzoquat (DFQ) in the acid soil studied. However, the lowest retention of DFQ in an acid soil can be increased by amendment with organic matter through a solid waste from wineries, and it is enough for duplicate retention a dosage rate of 10 t/ha. Anyway, detritivores ecology can still be affected. Detritivores are the organisms that consume organic material, and in doing so contribute to decomposition and the recycling of nutrients. The term can also be applied to certain bottom-feeders in wet environments, which play a crucial role in benthic ecosystems, forming essential food chains and participating in the nitrogen cycle.

Treatment of an Acid Soil with Bentonite Used for Wine Fining: Effects on Soil Properties and the Growth of Lolium multiflorum

When used to fine wines, bentonite acquires a protein load that makes it a potentially useful fertilizer. Other properties of bentonite are also potentially useful for soil amendment. In the work described in this paper, waste bentonite from a winery was applied to an acid soil, and its effects on soil properties and on the growth of Lolium multiflorum were evaluated. Soil N, K, and P contents all increased, as did pH and cation exchange capacity. Biomass production increased as the dose of bentonite increased up to 5 g kg(-1), decreasing at larger doses (possibly as a result of falling potassium/magnesium ratio and increasing electrical conductivity). Environmental drawbacks of waste bentonite include its high soluble copper content, although its conversion in the soil to less soluble forms reduces its potential phytotoxicity. The copper, manganese, and zinc contents of the ryegrass crop were low.

Co‐composting of Acid Waste Bentonites and their Effects on Soil Properties and Crop Biomass

Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.

Effects of recycled bentonite addition on soil properties, plant growth and nutrient uptake in a tropical sandy soil

The only way to increase the low CEC of sandy tropical soils over the long term is to apply high CEC materials such as 2:1 clay minerals. Acid activated bentonite is used in Thailand in the vegetable oil industry during the clarification process. The waste bentonite is discarded afterwards. The aim of the study was to compare the effects of the addition of these oil bentonites (OB) with the addition of cation beneficiated bentonite (BB) on soil properties and plant growth. Palm, rice and soybean OB, and bentonite beneficiated with calcium, magnesium, and potassium were applied at rates between 5 and 40 t ha−1 to an Arenic Acrisol. Three consecutive crops of sorghum were grown in pots. Biomass and plant nutrient content were determined at each growth phase, and selective soil properties were measured at the start and the end of the study. Beneficiated bentonite was not water repellent, but the addition of OB resulted in soil water repellency. The application of bentonite at the rate of 40 t ha−1 increased the cation exchange capacity (CEC) from 0.6 cmolc kg-1 in the control to 1.9 and 0.7 cmolc kg−1 in the BB and OB, respectiveley. The lower value of the CEC for OB compared to BB was probably due to the activation process and oil coating. OB applications at rates higher than 20 t ha−1 did not increase biomass, and biomass decreased with increasing water repellency. The other treatments produced a higher biomass than the control. However biomass was below potential because of widespread nitrogen deficiency. Exchangeable K was exhausted in two crops, whatever the initial level, stressing the issue of K management in this soil type. Soybean OB is a promising material for soil chemical properties and biomass production, probably because of its low oil content.

The qualifications of bentonite as a soil sealant

Wyoming bentonites have been used as liners to impound solid and liquid waste for several decades. The information in the scientific and engineering literature dealing exclusively with bentonites has been rather scant to this date. There is no shortage of information on clays in general. The bentonite producers are probably the ones which have the most data and experience with bentonite liners, but many keep their data confidential. The purpose of this paper is to assist the engineer who designs liners in his approach, and to avail some of the data on bentonite—waste interaction which the author has collected over a period of 10 years. Bentonites are applicable in many stressed situations, if the engineer and the contractor know how to deal with it and understand the limitations of the material. A bentonite can degrade in its swelling ability due to organic and inorganic contaminants, but it can also be rejuvenated by addition of sodium carbonate in clean water, although its swell will not be as high as initially. This paper presents an overview of the data collected during the author's activity in the bentonite business, and of published data and descriptions of bentonite liner practices in the United States.