Clay Type Research Articles

Effect of the addition of organic wastes (cork powder, nut shell, coffee grounds and paper sludge) in clays to obtain expanded lightweight aggregates

Four organic solid wastes (coffee grounds, ground nut shell, paper money sewage sludge and cork powder) have been investigated as bloating inducing agents in lightweight aggregate (LWA) manufacturing when mixed in small proportions (2.5wt.%) with three types of clays. The pellets obtained were fired in a rotary kiln at the maximum feasible temperature for 4min. A similar impact was observed both in the working conditions and in the properties of the LWAs, showing that the differences between said residues are not as decisive as those of the clays to which they are added. The organic wastes have played a crucial role in achieving reducing conditions inside the aggregate. Thus, their addition has led to substantial improvements both from an operational point of view, lowering the working temperature, and from a technological perspective, favoring bloating and the development of a highly porous and lightweight structure. Leachate studies have shown that the LWAs meet the regulatory limits. The outcomes of this investigation show that, in line with the precepts of the Circular Economy, the recovery of organic wastes of different nature can have a place in the production of environmentally friendly LWAs.

Effects of sodium adsorption ratio and electrolyte concentration on soil saturated hydraulic conductivity

Sodium adsorption ratio (SAR) and electrolyte concentration (EC) can significantly affect water movement in soil. However, the theoretical mechanisms behind it are rarely studied. In the present study, an analytical function between electrostatic repulsive pressure (PEDL) and SAR/EC was derived in Na-Ca mixed electrolyte solutions or soil water. Soil water SAR and EC controls PEDL through surface potential and midpoint potential between two adjacent soil particles, which consequently influences the saturated soil hydraulic conductivity (Ks). Theoretical calculations show that the PEDL decreases with increasing EC and increases with increasing SAR, and the reduction in Ks is correlated with the repulsive PEDL. Five soils of different dominant clay minerals, specifically kaolinite (K), illite (I) and montmorillonite (M), were used to investigate the relationship between PEDL and change of Ks. The soils were packed in columns and leached with a serial of solutions (constant EC values of 0.5, 1, and 2 ds m−1, respectively) with increasing SAR from 0 to infinity. Our study showed that the Ks decreases with increasing PEDL. At the inflection point of the percent of Ks reduction (Kred) vs. PEDL curve, the critical PEDL values are 8.358 ∼ 8.569 atm and Kred > 92% for the Mungana soil (M), Yarrandoo soil (M, K) and Dunholm soil (M), while the average critical PEDL value is about 12.34 atm and Kred is only ∼51.75% for the Urrbrae soil (I) and Timberlea soil (K). For a given soil, the PEDL is the determinant factor, while other factors such as soil texture and clay type can also affect Ks.

Hydrate formation and dissociation characteristics in clayey silt sediment

The geological occurrence of natural gas hydrates in clayey silt sediments has been extensively confirmed. Compared with sandy sediments, clayey silt is characterized by a large specific surface area, high capillary pressure, and high bound water content, which leads to distinct characteristics of hydrate formation and dissociation. The formation and dissociation of methane hydrates in clayey silt sediments with illite or montmorillonite were experimentally investigated. It was determined that an increase in the water content of silt and illite-silt sediments from ~9.47% to ~28.41% caused a decrease in the water-to-hydrate conversion ratio owing to the formation of a hydrate film between water and CH4 gas. However, in montmorillonite-silt sediments, the water-to-hydrate conversion rate increased between 9.47% and 18.94% of water saturation and decreased between 18.94% and 28.41% of water saturation under the combined effects of weakly bound water content and capillary pressure. In the hydrate dissociation experiment, the temperature of sediments with ~9.47% water content decreased more, which was caused by the smaller specific heat capacity of sediments with lower water content. Meanwhile, the temperature drops below the freezing point during the hydrate dissociation process, which is caused by the strong inhibition of hydrate phase equilibrium by montmorillonite. This study demonstrates the effects of clay type and water content on hydrate formation and dissociation, which is helpful for understanding the production behavior of clayey silt hydrate reservoirs.

Technical Assessment of Secondary Sedimentation Process in Copper Sulphide Tailings with the Presence of Clays, in Continental and Sea Water

Recovery of process water for recirculation is crucial, as the cost of adding additional fresh water is an economic constraint that is often prohibitive. Solid–liquid separation is a key process in the recovery of water resources. Therefore, research is needed to understand how fine particles, particularly quartz, kaolinite and sodium bentonite, impact the optimal separation process. In the present work, the effect of the presence of these clays in the solid–liquid separation of synthetic copper sulfide tailings is evaluated, quantifying the impact on the separation efficiency, considering the average settling rate and the turbidity of the supernatant. The physicochemical variables that control the suspension were monitored and the observed trends were explained by variations in properties such as zeta potential and pH. The characterization and quantification of the impact of the clays in the operation will allow us to lay the foundation for the development of a novel approach for the secondary treatment of the cloudy supernatant water of the thickeners. After the study, disparate effects on sedimentation efficiency could be distinguished depending on the type of clay and the water in which it is immersed. While in the case of tailings with the presence of kaolinite clays it is seen that the higher sedimentation efficiency occurs in the case of flocculation in distilled water, the salinity or presence of cationic coagulants is detrimental to it. In the case of tailings with the presence of bentonite clays, the sedimentation efficiency increases as there is a higher concentration of cationic salts (coagulation-synthetic sea water). In contrast, in the case of distilled water, the flocculation efficiency is very low, so it is recommended to add a cationic additive, which is supported by an associated low economic cost. In the case of tailings with the presence of ultrafine quartz content, a clear effect in the increase or decrease of sedimentation efficiency cannot be distinguished with the addition of flocculants, coagulants, or when working in sea water. Overall, the results suggest the convenience of splitting thickening and clarification as two distinct unit processes that may be treated using flocculant and salts, according to the fine mineral contents.

Microstructural Analysis of the Reactivity Parameters of Calcined Clays

Four (04) different types of clays from Burkina Faso were studied for their potential applications in the production of calcined clays as substitution materials for Portland cement. The study aimed at analyzing the factors affecting their reactivity. The untreated clays were subjected to various tests to highlight the intrinsic properties that can influence their reactivity. After the treatment by calcination, the clays were subjected to various pozzolanicity tests and microstructural analysis in order to evaluate their influence on the microstructure of the cement paste. The results showed that the reactivity of calcined clays is strongly related to the intrinsic properties of the raw clays, such as the content and the structure of kaolinite: disordered kaolinite reacts better than ordered kaolinite. After the calcination, the reactivity depends on the amorphous phase (amorphous content) of the clays, which influences the strength activity index. This study established a correlation between different parameters to easily identify the main properties of calcined clays that can influence their pozzolanic reactivity. All the results showed that the kaolinite content is a determining factor in the reactivity of clays before calcination. However, the study showed that the amorphous content of kaolinite is the determining parameter of the reactivity of calcined clays, as calcination can lead to the recrystallization of kaolinite.

Wound Healing Properties and Structural Analysis of Four Geographical Areas’ Natural Clays

Clays are fine particle materials that harden after drying. The difference in their structure is the key to their efficacy and their subsequent application. The current study aims to evaluate the wound healing property of four countries (C1:Iraq, C2:Turkey, C3:Azerbaijan and C4:Russia) clay samples by excision model using Sprague dawley rats also the chemical analysis of the samples was performed using X-ray diffraction (XRD) and X-ray Fluorescence (XRF) methods. Results revealed that the best wound healing activities were given by C1, C3, C4 and C2 respectively with healing percentages (76%, 71%, 62%, and 60%), respectively. XRD results revealed the presence of Calcium carbonate and CalciumMagnesium carbonate in C1, Dolomite and Calcium-Magnesium carbonate in C2, Cobalt Tantalum Sulfide in C3, Finally Quartz and Silicon Oxide in C4. On the other hand, XRF analysis showed the appearance of different major and trace elements with different quantities in each clay type. We conclude that different countries clays enclose wound healing property with diverse ranges and this diversity is due to their chemical and mineral structures.

X- Ray Diffraction Studies of Patti Claystone Member of the Campano-Maastrichtian Patti Formation, Southern Bida Basin, North Central Nigeria

X-ray diffraction and field studies were carried out on the Patti Clay Member of the Patti Formation in the southern Bida Basin. The studies involved field collection of samples and XRD laboratory analysis of clay samples in order to determine the dominant clay type, subordinate associated minerals, geologic processes and paleoenvironment of deposition. Field study involved standard litho-description by noting textural properties, facies type, fossil presence, structure and diagenetic effect. Laboratory XRD analysis procedure included sample grinding, XRD recording condition, selection and measurement of reference minerals, quantification of clay minerals using XRD processing software, XPert-Highscore Plus to generate results indicating clay mineral type and other minerals peaks. Lithostratigraphic section is dominated by the alternation of sandstone and claystone layers. The sedimentary structures are planar parallel and cross bedding in nature. The sandstone at Ahoko and along Lokoja-Abuja highway is characterized by liesegang ring and bioturbation structures. XRD results indicated that the Patti Clay Members are dominated by kaolinite with subordinate illite, montmorillonite and zincite in rare cases. The clay members were suggested to be deposited by moderate to low energy of transportation, moderate to low rate of deposition through prograding mechanism in a marginal marine setting. The kaolinite clay was formed by meteoric water reaction with the shallow-seated clay members through leaching of K+, Na+ and silica ions with resultant kaolinite stable at adequate pH that was not acidic.

The use of tannery waste in the preparation of clay roof tiles

Dried tannery waste (TW) powder was added in weight percentages ranging from 0 to 35% to replace the raw mix used for the preparation of roof tiles. This raw mix is composed of three different types of clays, feldspar, and grog. The samples were prepared by 15.6% mixing with water and molding in cuboid steel molds, the amount of mixing water being deduced from plasticity measurements. The dry samples were tested for linear shrinkage and mechanical strength. Firing was carried out at temperatures ranging from 1000 °C to 1150 °C in a muffle furnace following a pre-determined heating schedule. The fired samples were tested for sintering characteristics, efflorescence, frost resistance and mechanical strength. The results proved that it was possible to substitute up to 10% of the original mix by tannery waste powder to obtain roof tile samples on firing at 1100 °C abiding by ASTM C 1167 Standards for grades 2 and 3 roof tiles.

Factors Affecting Shrinkage Crack Development in Clay Soils: An Experimental Study

ABSTRACT Clay soils are widely used in constructing embankment dams, levees, highway embankments, sanitary landfills, and hydraulic barriers where they are compacted at maximum dry density and optimum water content. These structures are exposed to many cycles of wetting and drying during their service life, resulting in volume changes and developing shrinkage cracks. This study investigated the effect of density, water content, drying temperature, layer thickness, plasticity index, and multiple wetting and drying cycles on shrinkage crack parameters (length, aperture, and area). Five samples each of low-plasticity clay, medium-plasticity clay, and high-plasticity clay at water contents on both sides of optimum water content were compacted and then oven dried at temperatures of 10°C, 20°C, 30°C, 40°C, and 50°C. Upon complete drying, crack length, aperture, and area were digitally measured. Additionally, we saturated uncompacted clay layers of varying thicknesses (5, 7, 10, 20, and 30 mm) of the three clay types and oven dried them at the listed temperatures to investigate the effect of layer thickness on shrinkage crack parameters. The length, aperture, and area of the cracks were correlated with the influencing factors. Among the compacted samples, only high-plasticity clay samples developed shrinkage cracks, exhibiting an increase in crack length, aperture, and area with an increase in dry density and water content. For the uncompacted samples, crack length and crack area decreased with increasing layer thickness, whereas crack aperture increased.

Vitrification rate and estimation of the optimum firing conditions of ceramic materials from raw clays: A review

The present work is a review concerning the previous investigations on the vitrification behaviour of clays containing kaolinite, feldspars, muscovite (illite/sericite) and pyrophyllite. These clays are silico-aluminous and have interesting properties as raw materials for structural ceramics. The mineralogical and chemical composition were determined. Then, the vitrification in these clay samples using pressed bodies was investigated by few researchers in the temperature range 800–1350 °C with 0.5–5.5 h of soaking times. The effect of heat treatments on the degree of vitrification in these clays was characterized by bulk densities of the ceramic bodies at the fired stage. It was found some variations of bulk density values for all these clays fired in the range 1000–1150 °C, with marked decreases of the values obtained at 1200 °C and 1300 °C. A first order reaction kinetics was applied to the analysis of vitrification of the ceramic bodies under isothermal heating. The method is based on experimental data of bulk densities, being proposed for the estimation of the relative degree of vitrification resulting from different firing schedules. The analysis considered the temperature dependence of the rate of vitrification following Arrhenius behaviour. Thus, the vitrification activation energy can be obtained. The activation energies for the physical process of vitrification in these clays ranged from 45 to 151 kJ/mol. The relative rates of vitrification or degree of vitrification attained during heating and soaking were calculated. The results suggested that the contribution of vitrification due to heating in all these clays was relatively small compared to the vitrification during soaking. However, it was evidenced that the influence of the particle sizes in the thermal behaviour of these clays cannot be neglected. The vitrification rate equations, as deduced in these previous studies, can be useful tools to estimate the optimum firing conditions of these clays, allowing the extension of this method to other clay types.

Tl(I) adsorption behavior on K-illite and on humic acids

Cation sorption on clays and on humic acids (HA) has been extensively documented in scientific literature. Both are important components of natural environments, especially in soils, and therefore, innate competitors in the retention of metallic cations. The aim of this work was to investigate the sorption behavior of thallium (I) on a 2:1 type clay (IMt-2 illite, from silver Hill, Montana), and to compare it with its sorption behavior on HA. For this, a total of nine sorption isotherms of thallium on illite and/or HA were conducted at different pH values (3, 7 and 9). The sorption mechanism on illite was investigated by designing a novel cation exchange sorption model that incorporates an additional surface complexation mechanism (2pKa/3CE), where selectivity coefficients for 3 different types of exchange sites and a surface complexation constant for a pH-dependent site (≡SOH) at illite particle edges were obtained. In the case of Tl complexation by HA, investigation of the mechanism involved was done using the NICA-Donnan model.Sorption to illite showed increasing Tl+ uptake upon increasing pH from 3 to 9 by approximately one order of magnitude. Tl+ sorption on HA was also highly pH dependent, but slightly lower than on illite, although at low pH Tl+ complexation on HA was negligible.Geochemical sorption modeling on illite suggests that at very low Tl+ concentrations cation exchange Frayed Edge Sites were dominant at all pH values, after which at pH 3 and 7 the other interlayer cation exchange sites became the major contributors to sorption; while at pH 9 surface complexation of Tl(I) on the edge sites predominated, confirming the important variable-charge nature of illite and the strong competition that protons exert for binding of Tl(I) on these sites. In the case of modeling the Tl(I) binding to HA, complexation with the phenolic groups or high affinity sites present at the HA surfaces was predicted to be dominant, although at pH 7, the electrostatic component was dominant at the higher Tl+ concentration interval. The findings in this work contribute to further the understanding of two crucial geochemical mechanisms of Tl(I) retention in contaminated soils.

Flocculation of Clay-Based Tailings: Differences of Kaolin and Sodium Montmorillonite in Salt Medium.

Complex gangues and low-quality waters are a concern for the mining industries, particularly in water shortage areas, where the closure of hydric circuits and reduction in water use are essential to maintain the economic and environmental sustainability of mineral processing. This study analyzes the phenomena involved in the water recovery stage, such as sedimentation of clay-based tailings flocculated with anionic polyelectrolyte in industrial water and seawater. Flocculation–sedimentation batch tests were performed to ascertain the aggregate size distribution, the hindered settling rate, and the structure of flocs expressed through their fractal dimension and density. The aggregates’ properties were characterized by the Focused Beam Reflectance Measurement (FBRM) and Particle Vision Microscope (PVM) techniques. The impact of the type of water depends on the type of clay that constitutes the suspension. For quartz/kaolin, the highest performance was obtained in industrial water, with bigger aggregates and faster settling rates. However, the tailings composed of quartz/Na-montmorillonite reversed this trend. The type of water impacted the efficiency of primary-particle aggregation. The trials in industrial water generated a portion of non-flocculated particles, which was observed through a bimodal distribution in the unweighted chord-length distribution. This behavior was not observed in seawater, where a perceptible fraction of non-flocculated particles was not found. The additional cationic bonds that offer seawater favor finer primary-particle agglomeration for all tailings types.

Study of Molybdenite Floatability: Effect of Clays and Seawater.

Current challenges in froth flotation are the presence of complex gangues and the use of low-quality waters, such as seawater. In this scenario, the recovery of molybdenum minerals is difficult, mainly due to the hydrophobic faces’ physicochemical changes. In the present study, the natural floatability of pure molybdenite was analyzed by using microflotation assays, and hydrophobicity was measured by performing contact-angle measurements. The impact of two clays, kaolin (non-swelling) and Na-montmorillonite (swelling), was studied. The behavior in freshwater and seawater at pH 8 was compared, considering the current condition of the Cu/Mo mining industries, which use seawater in their operations. The presence of clays lowered the natural floatability of molybdenite precisely because they adhere to the surface and reduce its contact angle. However, the intensity with which they cause this phenomenon depends on the type of water and clay. Kaolin strongly adheres to the valuable mineral in both freshwater and seawater. For its part, Na-montmorillonite does it with greater intensity in a saline medium, but in freshwater, a high concentration of phyllosilicate is required to reduce the hydrophobicity of molybdenite. The clays’ adherence was validated by scanning electron microscopy (SEM) analysis.

Engineering Properties and Slope Inventory of Clayey Soil from the Trusmadi Formation in Bundu Tuhan, Sabah

The study area in Bundu Tuhan mainly consists of the metasedimentary rock of the Trusmadi Formation. Trusmadi Formation aged Palaeocene to Middle Eocene made up of interbedded dark grey shale and thin sandstone that shows the characteristics of deep marine sediment. Shale bed also known as phyllite unit is the major rock unit in Trusmadi Formation that is usually weathered and produced clayey soil. Clayey soil is often acknowledged as problematic soil due to its properties that tend to hold water highly compared to sandy soil, which will cause further engineering problems due to the soil creeping. The study area is prone to landslide activity, especially in the Trusmadi Formation’s slopes. Hence, this paper aims to determine the engineering properties of clayey soil from the Trusmadi Formation. Two slopes were also selected for laboratory analysis and slope inventory. The results of the analysis show that both samples are poorly sorted materials which are classified as sandy and silty clay soil and silty clay soil. The moisture content is 25.98% to 37.10%, specific gravity ranged from 2.52 to 2.57, and plasticity index ranged from 21.68% to 23.91%. The soil has inactive to a normal type of clay (0.59 to 0.97) with a very high swelling capacity (9.29% to 11.43%). The maximum dry density (MDD) ranged from 1.44 to 1.53 and optimum moisture content (OMC) of 25.47% to 25.67%. Also, both samples are classified as impermeable soil with a K value ranging from 1.74x10−8 m/s to 2.45x10−8 m/s. While, based on the slope inventory inspection, both slopes were comprised of metagreywacke, where the first slope was an embankment slope, and the second slope was a cut slope. The first slope has poor vegetation cover which leads to moderate erosion and instability that further caused failure which is rotational debris slide. As for the second slope with average vegetation cover, there is only minor erosion and instability present on the slope, and this slope also shows slow soil movement that indicates soil creep.

Rumen Fermentation of Feed Mixtures Supplemented with Clay Minerals in a Semicontinuous In Vitro System.

Simple SummaryMineral clays are included in the diets of ruminants to maintain health and improve productive performances. The inclusion of several types of mineral clay (zeolite, Z; bentonite, B; and sepiolite, S) in diets with different concentrate-to-forage proportions (65:35, HC, and 35:65, HF) was tested in vitro. In HC diets, the effect of Z manifested in a higher pH in the first part of fermentation, which can be related to a more stable rumen environment. The extent of substrate fermentation was lowest with S when added to the HC diet but was lowest with B when added to the HF diet. The response of the rumen environmental conditions and the extent of fermentation depends on the interaction between the type of clay and the proportion of concentrate and forage in an animal’s diet.Interest in using clays in the diets of ruminants to improve health and performance is increasing. The microbial fermentation of 65:35 (HC) or 35:65 (HF) concentrate:forage feeds, alone or with zeolite (Z), bentonite (B), or sepiolite (S), was studied in an in vitro semicontinuous culture system. The medium pH was allowed to drop for the first 6 h and was gradually buffered thereafter. For the HC diet, the medium pH was higher with Z throughout incubation (p < 0.05). Similar results were observed for the HF diet, but with lower differences between the additives. Throughout incubation, the volume of gas produced was higher with HC than HF (p < 0.05). The gas volume with S was the lowest (p < 0.05) for HC, whereas for HF it was lowest with B from 8 h onwards (p < 0.05). No treatment differences (p > 0.05) were observed in dry matter disappearance, microbial mass, or volatile fatty acids. However, the inclusion of B in HC reduced the ammonia concentration at 6 and 12 h with respect to C (p < 0.05). The inclusion of zeolite as an additive in the diets of ruminants stabilizes the rumen environment during the first stages of fermentation in terms of pH and ammonia concentration, especially in high-concentrate diets. The buffering effect of bentonite and sepiolite was lower, and both might reduce ruminal microbial fermentation, depending on the concentrate proportion.

Formation efficiency of soil organic matter from plant litter is governed by clay mineral type more than plant litter quality

Plant litters incorporated in soils are decomposed by microorganisms and partially transformed into soil organic matter (SOM) through mineral-organic association and physical protection in soil aggregates. Few studies have linked the effects of clay mineralogy and plant litter quality on controlling the formation efficiency of SOM. Using model soils, the objectives of this study were (1) to determine the effects of clay mineral type and plant litter quality on soil respiration dynamics, and formation efficiency of SOM, physical fractions, and chemical and microbial compositions of SOM at the end of a 120-day incubation; (2) to unravel SOM protection mechanisms and extents by specific clay minerals; and (3) to understand the key role of clay minerals relative to plant litter quality in controlling SOM formation. The changes in X-ray diffraction peak intensity (in terms of peak height) of the clay minerals during incubation and after H2O2 treatment provided evidence for surface adsorption by vermiculite and pore entrapment by kaolinite and illite assemblages. The SOM protection extent parameter, defined based on accumulative soil respiration dynamics, explained well the variation of the formation efficiency of mineral associated SOM (MAOM) and, to a lesser extent, that of occluded particulate SOM (oPOM) in aggregates. 90–96% of plant litter-derived C was protected in the vermiculite material and 33–60% in the pure kaolinite and illite materials. The pure vermiculite material showed the greatest fractions of MAOM and oPOM, the highest relative abundances of O–alkyls and anomeric from carbohydrates in the MAOM fraction. < 1% of plant litter-derived C was transformed into microbial biomass and residues, and fungal residues only were associated with the pure vermiculite material. These results suggested that plant litter incorporated into the soil was decomposed mainly through the ex vivo modification pathway and transformed into SOM through both mineral-organic association and physical protection pathways. Plant litter-derived C was likely protected through mineral-organic association from the earlier stages of decomposition by vermiculite than kaolinite and illite, resulting in more plant carbohydrates associated with vermiculite. Therefore, clay minerals determined SOM formation pathways and played a greater role in controlling SOM formation efficiency than plant litter quality.

Application of nanocomposite polyelectrolytes for the removal of antibiotics as emerging pollutants in water

In this work, nanocomposite polyelectrolytes (NCPs) based on alkylated chitosan macromonomers, ionic monomers, and 2D nanofillers of montmorillonite clay types were used to eliminate emerging contaminants, such as amoxicillin (AMX), tetracycline (TET), and ciprofloxacin (CIP), in water. For the removal studies, the effects of pH, ionic strength, amount of adsorbent, and kinetic and isothermic processes were studied. Removal percentages of 65.0, 81.4, and 76.7 were obtained at pH 9.0, 11.0, and 11.0 for CIP, TET, and AMX, respectively. It was also demonstrated that as the ionic strength increased, the elimination percentage decreased due to competition between sodium and chloride ions for the active sites on the adsorbent. Higher adsorption was obtained at an adsorbent dose of 0.03 g for CIP, AMX and 0.02 g for TET. The adsorption kinetics showed that both the pseudo-first-order model and pseudo-second-order model described the adsorption process, and the maximum adsorption capacity was at 30 min due to the availability of active sites present in the NCPs. Regarding the maximum retention adhesion capacity, the Langmuir isotherm was described as measuring values of 58.6, 291.7, and 97.6 mg g−1 for CIP, TET, and AMX at 298 K, respectively.

ANALISIS KAPASITAS DUKUNG FONDASI GEDUNG PELAYANAN UMUM DAN KEMAHASISWAAN POLITEKNIK KESEHATAN GORONTALO BERDASARKAN DATA SONDIR

The Research objectives are to achieve the foundation support capacity of the wells by referring to the sample of sondir data research conducted by the UNG laboratory. It is located in Moodu village, East city district, Gorontalo city. The research method used quantitative methods by recalculating the burden that can be borne by the foundation of the well.the soil conditions in Gorontalo Province, especially Gorontalo, are of clay type soil. In this study, the secondary data was take from quantitative methods where the relevant agencies concern to the form of sondir data. To process it, the writer uses 2 analytical equations to calculate the bearing capacity of the well foundation. Through put processing, it will get some results that usefull as a reference for the construction of the building. Then, it makes the results are more accurate. Based on the evaluation results, the construction of this building at point 1 with a depth of 2.80 m and a diameter of 1.20 m is 209.67 tons - 219.23 tons, while at point 2 with a depth of 2.80 m and a diameter of 1.20 m is 186.79 tons - 198.23 tons.

Solid Acid Catalysts for the Hock Cleavage of Hydroperoxides

The oxidation of cumene and following cleavage of cumene hydroperoxide (CHP) with sulfuric acid (Hock rearrangement) is still, by far, the dominant synthetic route to produce phenol. In 2020, the global phenol market reached a value of 23.3 billion US$ with a projected compound annual growth rate of 3.4% for 2020–2025. From ecological and economical viewpoints, the key step of this process is the cleavage of CHP. One sought-after way to likewise reduce energy consumption and waste production of the process is to substitute sulfuric acid with heterogeneous catalysts. Different types of zeolites, silicon-based clays, heteropoly acids, and ion exchange resins have been investigated and tested in various studies. For every type of these solid acid catalysts, several materials were found that show high yield and selectivity to phenol. In this mini-review, first a brief introduction and overview on the Hock process is given. Next, the mechanism, kinetics, and safety aspects are summarized and discussed. Following, the different types of heterogeneous catalysts and their performance as catalyst in the Hock process are illustrated. Finally, the different approaches to substitute sulfuric acid in the synthetic route to produce phenol are briefly concluded and a short outlook is given.

The Effect of Freeze-Thaw Cycling and the Initial Mass of Water on the Unfrozen Water Content of Calcium Bentonites Modified by Copper Ions

This research was conducted with the use of the DSC method; it involved the examination of the unfrozen water content in two model (source) calcium bentonites (≥75% smectite), after one to three freeze-thaw cycles in the natural state, as well as after the ion exchange for a potentially toxic element (Cu2+). The freeze-thaw cycles do not affect the unfrozen water content at a given negative temperature in a statistically significant manner. However, a statistically significant influence of temperature, the initial mass of the water, and the clay type on the change of the unfrozen water content was found. Moreover, the empirical models of predicting the unfrozen water in the bentonite after the exchange for Cu2+ ion were created, for which the parameter was the mass of the water and the mass of the dry soil, at the temperature of −2 °C.