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Natural zeolite is commonly used as an adsorbent for road dust suppression due to its excellent moisture absorption properties. However, during the formation process, natural zeolite tends to accumulate some zeolite water, organic impurities, and metal cations that occupy the pore channels and cavities, thereby blocking the passage of water molecules and hindering their adsorption. This study aims to improve the weak moisture absorption rate and capacity of dust suppression asphalt mixtures caused by clogged pores and impurities in natural zeolite. To achieve this different concentrations of salt solutions (NH4Cl, NaCl, MgCl2, and CaCl2) are used as modifiers for the treatment of natural zeolite. Scanning electron microscopy and Fourier transform infrared spectroscopy are used to study the interface and functional group changes between the modified zeolite substrate and asphalt mixture. The nitrogen adsorption/desorption curves of asphalt mixtures with different dosages were obtained using a nitrogen adsorption instrument. Based on this, parameters such as the specific surface area and adsorption pore volume of natural zeolite and modified zeolite asphalt mixtures were calculated using the BET and BJH methods. A macroscopic dust suppression test was further conducted to evaluate the dust suppression effect of the modified zeolite asphalt mixture on PM10. The results show that the moisture absorption rate and capacity of the modified zeolite are significantly improved. 20wt.%CaCl2 modification performs the best, and the moisture absorption capacity of the modified zeolite can reach up 10 times that of natural zeolite. Compared to the natural zeolite asphalt mixture, the specific surface area of the modified zeolite asphalt mixture is increased by 16.52%, and the adsorption pore volume is increased by 44.9%. The addition of modified zeolite powder significantly improves the dust suppression performance of the asphalt mixture. When the dosage of modified zeolite powder reaches 80%, the dust suppression effect reaches its peak, with an improvement of 16.34%. [ABSTRACT FROM AUTHOR]

Considering that industrial wastes such as granulated blast furnace slag (GBFS) and fly ash (FA) will be released less or more in the future, developing geopolymer composites with natural pozzolans is a critical issue today. In this study, geopolymer composites with different SS (sodium silicate)/SH (sodium hydroxide) rates (2.0, 2.5 and 3.0) were produced by NZ reinforcement at 5%, 10% and 15%, and their physicomechanical, transport, high-temperature resistance, microstructure, carbon footprint and cost features were investigated. Geopolymer composites had been heat-cured for 8 h at 80 °C. The porosity of geopolymer composites varies between 5.2 and 7.2%, while their water absorption is between 3.4 and 6.9%. The dry unit weight of all geopolymer composites is less than 2300 kg/m3. The compressive strength of the geopolymer composite with an SS/SH rate of 3 and an NZ rate of 5% was about 75 MPa, and the compressive strength of the geopolymer composite with an SS/SH rate of 2 and an NZ rate of 15% was about 40 MPa. The capillary water absorption value of geopolymer composites is generally less than 1 kg/m2. While the compressive strength of geopolymer composites exposed to 600 °C ranged from 21.2 to 40.5 MPa, using 5% and 10% NZ generally improved the high-temperature resistance. The carbon emission of geopolymer composites was between 391.4 and 400.8 kgCO2/kg, while the cost increased only slightly with increasing NZ content. As a result, NZ content of 10% when the SS/SH rate is 2.5 and NZ content of 5% when the SS/SH rate is 3 improves many features of geopolymer composites. [ABSTRACT FROM AUTHOR]

BACKGROUND: Developing robust technologies to remove emerging pollutants from water is urgent since conventional treatments are not technically prepared to remove them. This paper investigated the ibuprofen (IBU) adsorption capacity onto natural zeolite (NZ) and hydrothermally modified zeolite in an acidic medium followed by impregnation with the cationic surfactant cetyltrimethylammonium bromide (CTAB) (MZHT‐CTAB). The materials characterization included scanning electron microscopy (SEM), X‐ray diffraction (XRD), atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG), N2 adsorption/desorption isotherm (BET), Zeta Potential (ZP), and Point of Zero Charge (pHPZC). The adsorptive capacity studies were carried out by varying the pH solution, a kinetic study at three concentrations (25, 50, and 100 mg L−1), and the contaminant concentration influence (5–100 mg L−1). RESULTS: The results showed that the MZHT‐CTAB obtained both the highest removal efficiency (~ 37%) and the highest adsorption capacity (~ 14 mg g−1) at pH 5.0. The Pseudo Second‐Order (PSO) model, which showed the best fit to the experimental data, is significant as it indicates the reliability of our results. The maximum adsorption capacity for the concentration of 100 mg L−1 was 11.93 mg g−1. According to Giles's classification, the isotherm was classified as S‐3 type, indicating the competition between the adsorbate and water molecules for the active sites on the adsorbent surface. CONCLUSION: The adsorption studies demonstrate that the novel adsorbent (MZHT‐CTAB) is highly effective in removing IBU, presenting a significant removal capacity and feasibility. This promising result contributes to the ongoing search for alternative materials for water treatment. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The present study aims to investigate how the use of high‐range water reducer (HRWR) and variations in water/cement (W/C) ratio affect the properties of self‐consolidating concrete (SCC) while taking into account different proportions of polypropylene fibers (PF) and natural zeolite (NZ). A total of 28 samples were cast and analyzed. PF fractions ranging from 0% to 1.5% by weight were added, along with a substitution of 10% NZ for cement (50 kg/m3). Four W/C ratios (0.30, 0.35, 0.40, and 0.45) were tested, in addition to seven HRWR contents ranging from 5 to 6.5 kg/m3. Various tests were conducted to assess slump, T500, V‐funnel, L‐box, modulus of elasticity, and compressive, tensile, and flexural strengths. Novel models were developed to predict the properties of hardened concrete based on W/C, HRWR, PF, and NZ content. Findings indicated that optimal performance of PF‐reinforced SCC with NZ was achieved when up to 0.75% PF was combined with an HRWR content equivalent to 1.25% of the cement fraction and NZ ratio. Furthermore, the proposed models offer accurate predictions of both fresh and hardened‐state properties of PF‐reinforced SCC with NZ based on W/C and HRWR ratios. [ABSTRACT FROM AUTHOR]

In the framework of a circular economy, wastewater treatment should be oriented toward processes that allow the recovery of the resources present in the wastewater while ensuring good effluent quality. Nitrogen recovery is usually carried out in streams concentrated in this nutrient because these high concentrations facilitate nitrogen valorization. On the other hand, the mainstream of a wastewater treatment plant (WWTP) has a high potential for nitrogen recovery, but it is not usually considered because it is hard to manage due to its low nitrogen concentration. To solve this problem and facilitate the recovery of nitrogen in the mainstream, this work proposes ion exchange with zeolites as a stage of ammonium concentration, to provide a nitrogen-concentrated stream that could be valorized by another technology, while obtaining a nitrogen-free effluent. The working stream, the permeate of an AnMBR process in the mainstream, has suitable characteristics to be treated in an ion exchange column (free of suspended solids and with very low organic matter content). To this end, the effect of the working flow rate (17.5 to 4.4 BV/h) and the ammonium concentration (54 to 17 mg NH4-N/L) on the adsorption capacity of the zeolite in the loading phase was evaluated. The adsorption curves were fitted to three mathematical models: Thomas, Bohart–Adams, and Yoon–Nelson. The effect of the regeneration flow rate (from 8.7 to 2.2 BV/h) and the regenerant concentration (NaOH at 0.2, 0.1, and 0.05 M) on regeneration capacity and efficiency were also studied. A novel control strategy based on effluent conductivity was used in both phases to control the duration of the adsorption and regeneration phases. [ABSTRACT FROM AUTHOR]

The removal of Sunset Yellow (E110) on natural zeolite and zeolite modified with the cationic surfactant cetyl pyridinium chloride (CPC) was studied using the adsorption method. The structural characteristics of the surfactant-modified zeolite (SMZ-CPC) were investigated using X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, and the scanning electron microscopy (SEM) images. The effect of different parameters on the adsorption process, such as equilibration time and amount of adsorbent at 298 K, were determined using UV–Vis spectroscopy. The maximum dye removal percentage on SMZ-CPC was obtained with 0.08 g of adsorbent in 30 min. The results show that the zeolite modified with CPC surfactant (SMZ) has a higher adsorption capacity for Sunset Yellow than the unmodified zeolite (natural form). The experimental adsorption data were nonlinearly analyzed using isotherm equations such as Langmuir, Freundlich, Temkin, Langmuir-Freundlich (or Sips), and Extended Langmuir (EL). The experimental data were better fitted with the Sips isotherm. The adsorption kinetic data were analyzed using eight models in nonlinear forms: the pseudo-first-order (PFO), pseudo-second-order (PSO), integrated kinetic Langmuir (IKL), Elovich, intraparticle diffusion (IPD), mixed order rate equation (MOE), fractal-like pseudo-first-order (FL-PFO) and fractal-like pseudo-second-order (FL-PSO). According to the results of the coefficient of determination (R2), Elovich kinetic model well expressed E110 adsorption onto SMZ-CPC. Most of the dye removal takes place in less than 5 min and the maximum adsorption capacity is 5.06 mg/g. The results of this study show that zeolite modified with cationic surfactant is an effective adsorbent for removal anionic dyes from an aqueous solution. [ABSTRACT FROM AUTHOR]

Considering the increasing need for optimal use of water resources, using types of waste water instead of part of the water for making concrete and also reducing the use of potable water in concrete is particularly important, especially in developing countries. Accordingly, this study aimed to investigate and reinforce using greywater as a potential alternative to mixing water in concrete. The specimens' fresh, hardened, and durable properties from 14 concrete mix designs containing six mixing water types, three natural zeolite levels (0, 10, and 20%), and two silica fume levels (0 and 8%) were tested to achieve that. Mixing waters in this study consisted of distilled water, raw greywater, diluted greywater (50% greywater, 50% distilled water), simulations of greywater's salt and organic pollutants, and synthetic greywater. The results showed that raw greywater reduced average compressive strength by 8%, while diluted greywater caused a 1.5% increase instead. Mixing water standards requirements were satisfied on both raw and diluted greywater cases. The results also showed that the impact of greywater on the durability properties of concrete was non-critical in most cases, while diluted greywater, even slightly (4%), improved bulk electrical resistance (RCPT). The test results of synthetic waters showed that reducing chemically active salts and/or organic pollution in greywater can effectively increase the performance of the produced concrete. Using 8% silica fume as cement replacement improved the compressive strength of greywater-made concrete by up to 16% and reduced the cracks and porosity of the specimens based on SEM images. On the other hand, using 20% natural zeolite as cement replacement increased surface (using Wenner probes) and bulk chloride ion penetration by 36 and 78%, respectively. Based on these results, silica fume and natural zeolite replacement are impressive tools to reinforce greywater-made green concrete so that it can properly rival and even replace regular concrete even when using more polluted greywater. Furthermore, these replacements can be great potential alternatives to wastewater dilution or treatments. [ABSTRACT FROM AUTHOR]

Abstract The removal of Sunset Yellow (E110) on natural zeolite and zeolite modified with the cationic surfactant cetyl pyridinium chloride (CPC) was studied using the adsorption method. The structural characteristics of the surfactant-modified zeolite (SMZ-CPC) were investigated using X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, and the scanning electron microscopy (SEM) images. The effect of different parameters on the adsorption process, such as equilibration time and amount of adsorbent at 298 K, were determined using UV–Vis spectroscopy. The maximum dye removal percentage on SMZ-CPC was obtained with 0.08 g of adsorbent in 30 min. The results show that the zeolite modified with CPC surfactant (SMZ) has a higher adsorption capacity for Sunset Yellow than the unmodified zeolite (natural form). The experimental adsorption data were nonlinearly analyzed using isotherm equations such as Langmuir, Freundlich, Temkin, Langmuir-Freundlich (or Sips), and Extended Langmuir (EL). The experimental data were better fitted with the Sips isotherm. The adsorption kinetic data were analyzed using eight models in nonlinear forms: the pseudo-first-order (PFO), pseudo-second-order (PSO), integrated kinetic Langmuir (IKL), Elovich, intraparticle diffusion (IPD), mixed order rate equation (MOE), fractal-like pseudo-first-order (FL-PFO) and fractal-like pseudo-second-order (FL-PSO). According to the results of the coefficient of determination (R 2), Elovich kinetic model well expressed E110 adsorption onto SMZ-CPC. Most of the dye removal takes place in less than 5 min and the maximum adsorption capacity is 5.06 mg/g. The results of this study show that zeolite modified with cationic surfactant is an effective adsorbent for removal anionic dyes from an aqueous solution.

This novel research presents an investigation on petroleum products dehydration using the adsorption method by low-cost adsorbents. To investigate the performance of proposed process intended to separate emulsified water, synthetic stabilized water emulsions in different petroleum products (Gasoline, Kerosene, and Gas oil) which equal 300, 600, and 800 ppm were prepared. Afterwards, under batch conditions, natural zeolite and activated carbon as economic adsorbents were utilized for the dehydration process. The characteristics of adsorbent was examined using SEM and XRD analysis. The obtained results from BET analysis also depicted that the specific surface area of activated carbon was considerably more than that of zeolite. Results showed that both zeolites and activated carbon can effectively purify petroleum products from undesirable emulsified water. The comparison of the adsorbents' efficiency indicated that activated carbon has a higher affinity than zeolite for water in gasoline and gas oil, however, they had almost the same adsorption capacity in kerosene dehydration. The maximum water removal percentage of gas oil, kerosene and gasoline using zeolite was 84.84, 92.17, and 88.64, respectively. Dehydration by activated carbon also led to 86.44, 93.43 and 90.2 per cent water removal from gas oil, kerosene and gasoline, respectively. [ABSTRACT FROM AUTHOR]

In recent years, researchers are looking for ways to reduce the amount of sulfur in kerosene. Therefore, desulfurization of kerosene is considered an important commercial and environmental process. Among the hard and complicated methods available for the desulfurization process, natural zeolites can be a suitable alternative for the desulfurization of oil products due to their economic efficiency, biocompatibility, and natural abundance of oil reserves. In this research, natural zeolite (clinoptilolite) was modified with CuO nanoparticles and used as adsorbent for desulfurization of kerosene. The effect of important parameters such as adsorbent dose, pH of solution and initial adsorbate concentration were investigated. Results indicated the optimum conditions as follows: dose of adsorbent 2 g, pH 10 and the adsorbate dose 200 ppm. Results showed that the modified adsorbent is a suitable, low-cost and good efficiency for the desulfurization process of kerosene. [ABSTRACT FROM AUTHOR]

This study aims to produce diisopropyl ether (DIPE) via isopropanol dehydration using cobalt-phosphate-supported natural zeolite catalysts. The catalytic activities of the zeolite/CoO and zeolite/Co(H2PO4)2 were compared. The as-prepared catalysts were assessed using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and N2 adsorption-desorption. Surface acidity was determined using the gravimetric method with pyridine as the probe. The results of this study showed that natural zeolite was favorably impregnated by CoO and Co(H2PO4)2 species. The impregnation process affected the textural and acidic features of the catalysts. The zeolite/Co(H2PO4)2 catalyst with a loading of 8 mEq.g-1 exhibited the highest surface acidity of 1.827 mmol.g-1. This catalyst also promoted the highest catalytic activity towards isopropanol dehydration, with an isopropanol conversion of 66.19%, DIPE selectivity, and yield of 46.72% and 34.99%, respectively. The cobalt phosphate species promoted higher catalytic activity for isopropanol dehydration than the CoO species. This study demonstrated the potential of cobalt phosphate-supported natural zeolite catalysts for DIPE production with adequate performance. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Plastics, once regarded as a revolutionary material shaping modern society, now pose an unprecedented threat to our environment. Household solid waste sorting stations produce several fractions, one of which contains a high concentration of Low-Density Polyethylene (LDPE) film waste (packaging, sunscreen film, etc.). This fraction is difficult to recycle because it contains quite a lot of impurities. Usually, it is sent to cement factories that burn it together with other fuels. However, with some processing techniques such as catalytic pyrolysis, this fraction could be valorized. In this paper, experiments were carried out in batches at a laboratory-scale installation, with a processing capacity of 1–3 kg of waste. A pyrolysis reactor was connected to a distillation column, enabling separation of the fractions. The gaseous and liquid fractions were characterized by GC-FID-TCD (gases) and GC-MS (liquids) analysis. Natural catalysts such as bentonite or clinoptilolite were studied and used in the melting of plastic mass to simplify the process as much as possible. To test the activity of the catalysts, the pyrolysis of LDPE granules was initially studied. It was found that natural zeolites are much more active than bentonite and that a minimum concentration of 5–10% is needed to have a positive effect on the composition of the fractions (increasing the weight of the light fractions (C1–C6, C6–C10, and C11–C13) in relation to the heavy fractions (C13–C20 and C20+). Catalytic pyrolysis gives a completely different distribution of light hydrocarbons. The best catalyst selected from LDPE lab experiments was then tested upon the pyrolysis of plastic film waste obtained by a waste treatment plant. The research objective reported in this paper was to obtain a fraction of combustible gases in the largest possible proportion, which can be much more easily exploited by burning in an engine that drives an electric generator. [ABSTRACT FROM AUTHOR]

The present study reports the surfactant modification of Bolivian natural zeolite with hexadecyltrimethylammonium bromide (HTDMA-Br) for the adsorption of hexavalent chromium Cr (VI) anions from water. The surfactant-modified natural zeolite was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms, and Fourier-transform infrared spectroscopy (FTIR) to analyze the effect of its modification with HTDMA-Br and to verify its charge on the zeolite surface. We report a maximum adsorption capacity of 17 mg/g of Cr (VI) anions, surpassing the findings of some of the previous investigations on surfactant-modified natural zeolites of different geological origins. The analysis of the equilibrium data described the Cr (VI) anions adsorption by Langmuir isotherm and the pseudo second-order kinetic model. In addition, thermodynamics revealed an exothermic adsorption. Furthermore, anion exchange, electrostatic attraction, and chemical reduction were indicated to be dominating sorption mechanisms by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) characterization techniques. [ABSTRACT FROM AUTHOR]

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Understanding the thermal properties of zeolites is crucial for their industrial applications. This study explores the thermal stability and dehydration process of clinoptilolite using high-temperature X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Clinoptilolite's thermal decomposition was monitored from 25 °C to 1200 °C, with results analyzed based on its crystal structure. Principal components analysis (PCA) of the DRIFT spectra indicated progressive water removal and dehydration upon heating, leading to the formation of hydrogen bonds. Thermogravimetric analysis (TGA) revealed a two-step endothermic weight loss: initially, physically adsorbed water was lost up to 100 °C, followed by the removal of tightly bound water and hydroxyl groups until 800 °C. Clinoptilolite remained the dominant phase up to 800 °C, after which albite and cristobalite took over. Rietveld refinement showed that the sample initially contained 70% clinoptilolite, 24% albite, and 6% cristobalite. Above 800 °C, clinoptilolite disappeared, leaving 93% albite and 7% cristobalite. FT-IR spectra changes due to water loss were evident: drying of adsorbed water occurred up to 75 °C and minimal changes were observed from 75 °C to 135 °C, followed by further dehydration until 240 °C. Complete dehydration was confirmed by the disappearance of OH stretching vibration bands by 395 °C, consistent with TGA findings. [ABSTRACT FROM AUTHOR]

Enhancing food preservation and safety using environmentally friendly techniques is urgently needed. The aim of this study was to develop food packaging films using biodegradable poly-L-lactic acid (PLA) as biopolymer and carvacrol (CV) essential oil as an antioxidant/antibacterial agent for the replacement of chemical additives. CV was adsorbed onto natural zeolite (NZ) via a new vacuum adsorption method. The novel nanohybrid CV@NZ with a high CV content contained 61.7%wt. CV. Pure NZ and the CV@NZ nanohybrid were successfully dispersed in a PLA/triethyl citrate (TEC) matrix via a melt extrusion process to obtain PLA/TEC/xCV@NZ and PLA/TEC/xNZ nanocomposite films with 5, 10, and 15%wt CV@NZ or pure NZ content. The optimum resulting film PLA/TEC/10CV@NZ contained 10%wt. CV@NZ and exhibited self-healable properties, 22% higher tensile strength, 40% higher elongation at break, 45% higher water barrier, and 40% higher oxygen barrier than the pure PLA/TEC matrix. This film also had a high CV release content, high CV control release rate as well as 2.15 mg/L half maximal effective concentration (EC50) and 0.27 mm and 0.16 mm inhibition zones against Staphylococcus aureus and Salmonella enterica ssp. enterica serovar Typhimurium, respectively. This film not only succeeded in extending the shelf life of fresh minced pork, as shown by the total viable count measurements in four days but also prevented the lipid oxidation of fresh minced pork and provided higher nutritional values of the minced meat, as revealed by the heme iron content determination. It also had much better and acceptable sensory characteristics than the commercial packaging paper. [ABSTRACT FROM AUTHOR]

The design of blended cement with less clinker follows current construction material trends. This technique promotes energy efficiency, resource conservation, and CO2 reduction. This study proposes eco-friendly cement production methods that preserve concrete quality. To determine its potential for cement manufacture, Jordanian natural zeolite from almafrak (Amman, Jourdan) is tested for physical, chemical, and microstructural properties. Accordingly, the British standard mandates 6%, 10%, and 15% natural zeolite instead of clinker. The zeolite cement's chemical composition, physical properties, and microstructure were analyzed. With 6-15% natural zeolite replaced, zeolite cement has 23.29-25.99% silicon oxide, 4.92-6.22% aluminium oxide, 5.33-6.09% iron oxide, and 55.92-49.78% calcium oxide. The specific gravity of zeolite cement decreases by 5% when applied 15% natural zeolite. Zeolite cement had autoclave soundness of 0.1-0.17, fineness of 4930-5380 cm2/kg, initial setting time of 125-130 minutes, final setting time of 225-285 minutes, specific gravity of 3.04-2.97, and loss on ignition of 3.71-5. The compressive strength of blended cement with 6%, 10%, and 15% natural zeolite replacement is 20.48, 14.24, and 11.25 MPa after 2 days, respectively. Compressive strength is 35.8 MPa, 36 MPa, and 37.6 MPa after 28 days. Zeocement's fibrous substance, created by zeolite minerals and calcium hydroxide during hydration, makes it compact and consistent. This fibro structure improves interfacial connections, reducing microcracks, strengthening structural integrity, and making Portland cement mixtures more durable. [ABSTRACT FROM AUTHOR]

Zeolitic materials enriched in phosphorus and nitrogen, with a pronounced content for this last element, were obtained from natural clinoptilolite (CLI) treated with ammonium hydrogenphosphate (DAP) and urea. The interaction of phosphorus and nitrogen species retained on CLI was analyzed using different research methods. FTIR spectra showed the presence of NH4+, PO43− and urea on CLI. The retention of ammonium involves both ion-exchange in clinoptilolite, and adsorption. Phosphate is retained by adsorption, and it can be incorporated into an electrical double layer with accompanying cations including NH4+. The FTIR bands of the amino group of urea appear to be shifted relative to their location in the urea spectrum. This is associated with weakening of N–H bond from amino group due to its interaction with the clinoptilolite framework via hydrogen bonding. The urea is arranged on the zeolite surface, which is consistent with SEM observations and elemental (N and P) mapping by STEM. As a result, the surface area and micropore volume of these materials, treated with DAP and urea, decrease with respect to those modified with DAP alone. Accordingly, the release studies showed that the subsequent delivery of phosphorus species occurs in a delayed mode. These materials have great potential to be used as slow-release nutrient fertilizers for crop plants. They have a significant amount of nitrogen available on their surface, allowing plants to easily assimilate it early in their growing cycle. Zeolitic matrix leads to obtain materials at low-cost for massive applications, efficient use of nutrients and environmental benefits. [ABSTRACT FROM AUTHOR]

Rice husk is a type of agricultural waste that generated from rice production activities. The number continues to increase in line with the increasing food needs of the people in Indonesia. This study aims to determine the effect of the addition of natural zeolite as a catalyst and to determine the effect of natural zeolite mass percentage variation in the mixture on rice husk waste catalytic combustion by using the thermo gravimetric analysis method. The results of this study show that there is an effect of adding natural zeolite catalysts with the mass percentage of natural zeolite variations on the combustion characteristics and activation energy of each mixture. Increasing the mass percentage of natural zeolite catalysts can affect the reaction process become faster and minimize the effort required, but it was found that if the amount of natural zeolite catalyst is too much, it only adds to the heating load which causes slower reaction. The mixture of rice husks with 10% natural zeolite catalyst is the most optimal mixture because it has the lowest required activation energy value and the combustion reaction phases are achieved at a lower temperature than 5% and 15% mass percentage variations. [ABSTRACT FROM AUTHOR]

Zeolites of natural origin are materials exhibiting many positive effects on the human body. Silver-modified zeolites have already been introduced as bactericidal agents, although studies dealing with their toxicity are insufficient. This work describes the synthesis of activated and silver-loaded Bulgarian zeolite using a simple wet impregnation method. Morphological characteristics and compositions of natural zeolite, activated zeolite, and Ag-nanocomposites were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Silver loading is approximately 13 wt. %, with mean Ag particle size around 19 nm. Analyses of the samples included antioxidant activity assays based on ABTS radical scavenging ability and in vitro cytotoxicity tests with human normal fibroblasts and three adenocarcinoma cell lines. The experiments were performed with natural, activated, and Ag-modified zeolite in comparison to two commercial food supplements. Our results indicated moderate antioxidant activity of the tested samples. Silver-modified zeolite demonstrated cytotoxic effects against both tumor cells and normal fibroblasts, but the detected levels of inhibition were stronger against the adenocarcinoma cells, suggesting anti-tumor potential. The present article indicates a new aspect of Bulgarian natural zeolite and Ag-loaded zeolite biological activity. It highlights the need for detailed toxicity evaluations of Ag-nanocomposites prior to healthcare applications. [ABSTRACT FROM AUTHOR]

Natural zeolite is commonly used as an adsorbent for road dust suppression due to its excellent moisture absorption properties. However, during the formation process, natural zeolite tends to accumulate some zeolite water, organic impurities, and metal cations that occupy the pore channels and cavities, thereby blocking the passage of water molecules and hindering their adsorption. This study aims to improve the weak moisture absorption rate and capacity of dust suppression asphalt mixtures caused by clogged pores and impurities in natural zeolite. To achieve this different concentrations of salt solutions (NH4Cl, NaCl, MgCl2, and CaCl2) are used as modifiers for the treatment of natural zeolite. Scanning electron microscopy and Fourier transform infrared spectroscopy are used to study the interface and functional group changes between the modified zeolite substrate and asphalt mixture. The nitrogen adsorption/desorption curves of asphalt mixtures with different dosages were obtained using a nitrogen adsorption instrument. Based on this, parameters such as the specific surface area and adsorption pore volume of natural zeolite and modified zeolite asphalt mixtures were calculated using the BET and BJH methods. A macroscopic dust suppression test was further conducted to evaluate the dust suppression effect of the modified zeolite asphalt mixture on PM10. The results show that the moisture absorption rate and capacity of the modified zeolite are significantly improved. 20wt.%CaCl2 modification performs the best, and the moisture absorption capacity of the modified zeolite can reach up 10 times that of natural zeolite. Compared to the natural zeolite asphalt mixture, the specific surface area of the modified zeolite asphalt mixture is increased by 16.52%, and the adsorption pore volume is increased by 44.9%. The addition of modified zeolite powder significantly improves the dust suppression performance of the asphalt mixture. When the dosage of modified zeolite powder reaches 80%, the dust suppression effect reaches its peak, with an improvement of 16.34%.

Research has been carried out on making biodiesel from palm oil using natural zeolite catalysts impregnated with metal oxides such as zinc oxide and titanium oxide. This research aims to produce biodiesel using natural zeolite and ZnO-TiO2/NZ catalysts. The catalysts were analyzed using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscope (SEM), and Brunauer-Emmet-Teller (BET). The catalyst was tested in the transesterification reaction to produce biodiesel. The mole oil and methanol ratio varied from 1:15, 1:18, and 1:20. In addition, the biodiesel product was analyzed using Gas Chromatography-Mass Spectroscopy (GC-MS). The results showed the optimum condition for converting triglycerides to 1:18 variation of oil:methanol was 60.53%using a ZnO-TiO2/NZ catalyst. The ZnO-TiO2/NZ catalyst is very promising for use as a catalyst for converting palm oils into biodiesel.

In a previous study, the larger size of synthetic zeolite particles was highlighted as better choice for electrocoagulation combined with zeolite (ECZ). This choice resulted in a smaller rise in pH and temperature, a more significant decline in turbidity as well as chemical oxygen demand (COD), and lower electrode wastage, but with greater damage to the electrode surface. The focus of this study was to determine whether natural zeolite of three different particle sizes has the same effect on the ECZ process. The Taguchi method L9 was employed in planning the experiments, with particle sizes of natural zeolite ranging up to 600 μm, three different electrode materials (carbon steel, aluminium alloy, and sacrificial zinc anode), current density in the range of 0.003–0.018 A cm−2, and contact time in the range 10–30 min. The Taguchi optimisation results revealed a more significant decrease in COD and turbidity with the smallest particle size of natural zeolite used (90 µm) and with Al electrodes. Evidently, the zeolite particle size, together with the zeolite composition, had a significant influence on the reduction in COD and turbidity. Anode consumption ranged from 0.0172 to 0.6469 g, with minor cathode consumption evident on all electrode materials. Optical microscopy analysis indicated significant corrosion of the anodes, particularly with the largest natural zeolite particle size of 160–600 µm, while minor corrosion damage was also observed on the cathodes.

The industrial production of biogas, syngas, and hydrogen often relies on costly synthetic adsorbents and catalysts. However, natural zeolites (NZs) offer a cost-effective alternative, potentially enhancing reaction speeds as adsorbents, membranes, and catalysts. Despite their availability, the utilization of NZs and modified NZs in gas production and purification is underreported. This study aims to systematically review recent advancements in NZ modification techniques to optimize their role in generating, purifying, and enhancing biogas, syngas, and hydrogen. Bibliometric techniques were employed to analyze various NZ properties, including Si/Al ratio, surface area, microporosity, morphology, crystallinity, ion exchange capacity, and stability. Five primary modification methods—ion exchange, acid-base treatment, surface treatment, surfactant treatment, and plasma-assisted treatment—were assessed for their effects on improving gas production and purity. Key findings suggest that acid treatment, calcination, ion exchange impregnation, and coating can enhance critical factors such as Si/Al ratio and ion exchange capacity. However, achieving high selectivity across multiple gas combinations remains challenging due to the variable composition of biogas and syngas. Moreover, the sustainability and cost-effectiveness of NZ activation methods, along with the commercial viability of using modified NZs, require further investigation. This study offers valuable insights into NZ potential, guiding future research toward more efficient and sustainable energy production.

The use of natural zeolite clinoptilolite in preparing photocatalysts and its function in photocatalysis are discussed in this review. The importance of advanced oxidation processes (AOPs) and the potential of heterogeneous photocatalysis in removing environmental pollutants are emphasized. The review focuses on the synergistic effects of clinoptilolite with semiconductors (TiO2, ZnO, CuO, SnO2, and NiO) to prepare stable and active photocatalysts, highlighting recent advancements in this field. It explores clinoptilolite's structural characteristics, highlighting its microporous nature, adaptable framework, and improved textural properties due to acid and alkali treatments. Particle size, crystal phase, and calcination temperature are three key synthesis parameters that affect photocatalytic activity and are highlighted in the discussion of these parameters and their methods. A discussion is held regarding the processes and mechanisms of photocatalytic degradation of different organic compounds under varying irradiation conditions, including UV, visible, and ambient sunlight. Clinoptilolite is vital in improving supported semiconductor oxides' photocatalytic efficiencies, which aid in pollutant degradation and environmental remediation. [ABSTRACT FROM AUTHOR]

Research has been carried out on making biodiesel from palm oil using natural zeolite catalysts impregnated with metal oxides such as zinc oxide and titanium oxide. This research aims to produce biodiesel using natural zeolite and ZnO-TiO2/NZ catalysts. The catalysts were analyzed using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscope (SEM), and Brunauer-Emmet-Teller (BET). The catalyst was tested in the transesterification reaction to produce biodiesel. The oil and methanol mole ratio varied from 1:15, 1:18, and 1:20. In addition, the biodiesel product was analyzed using Gas Chromatography-Mass Spectroscopy (GC-MS). The results showed the optimum condition for converting triglycerides to 1:18 variation of oil:methanol mole ratio was 60.53% using a ZnO-TiO2/NZ catalyst. The ZnO-TiO2/NZ catalyst is very promising for use as a catalyst for converting palm oils into biodiesel. [ABSTRACT FROM AUTHOR]

The types and contents of minerals contained in natural zeolites vary depending on the production conditions. As a result, the adsorption properties of natural zeolites also vary depending on the production area. To utilize natural zeolites as adsorbents in various fields, it is crucial to identify the adsorption properties based on the type and content of minerals they contain. Therefore, this study aimed to analyze the adsorption characteristics of Cs and Sr using six types of natural zeolites from Mongolia (M-1, M-2, M-3, M-4, M-5, and M-6) to determine their potential as radioactive waste treatment agents. The experiments conducted showed that the adsorption equilibrium for Cs and Sr was reached within 4 and 8 h., respectively. Among the six samples, M-2 and M-6 exhibited relatively high adsorption rates, with Cs adsorption rates of 80% and 84%, and Sr adsorption rates of approximately 18% and 21%. Furthermore, the single-component isothermal adsorption experiments demonstrated that all six samples followed the Langmuir model. The maximum adsorptions of Cs was highest in M-2 (154.7 mg/g), M-4 (148.8 mg/g), and M-6 (150.2 mg/g) respectively. Additionally, the maximum adsorptions of Sr for M-2 and M-6 were 29.66 and 33.67 mg/g, respectively. It was observed that the natural zeolite with a higher content of 8-ring in the framework and higher CEC exhibited greater selectivity for Cs compared to the other six natural zeolites. Therefore, the maximum adsorption of Cs was attributed to the high total content of 8-rings in the natural zeolite framework, as well as the cation exchange capacity (CEC). [ABSTRACT FROM AUTHOR]

To improve the heat extraction efficiency from the wellbore fluids to the stratum in the geothermal well, thermal insulation cement, which is prepared by alkali-excited straw ash-natural zeolite, was based on the orthogonal test. The properties of thermal insulation cement, such as compressive strength, thermal conductivity and fluidity, were tested, and the comprehensive evaluation and range analysis of thermal insulation cement were carried out by using analytic hierarchy process (AHP) as a macro reference index. The results show that the alkali equivalent of natural zeolite and water glass are the two biggest factors affecting the properties of cement. The compressive strength of the optimal mixture at 38 °C and 60 °C for 8 h is 9.26 MPa and 24.46 MPa, respectively, and the thermal conductivity reduction rates at 30 °C, 60 °C and 90 °C are 42.41%, 50.29% and 54.03%, respectively. The initial consistency of the optimal mixture is 13.9 BC and the consistency time is 123 min, which can be used for engineering cementing. In addition, the thickening time of cement can be adjusted according to water-reducing agent and retarder to meet the actual construction requirements of cementing. [ABSTRACT FROM AUTHOR]

Adsorptive, catalytic, and antibacterial properties of clinoptilolite-rich tuffs (ZT) are presented here. ZT transformed into Fe-containing ZT (Fe-ZT) removes various organic and inorganic anions from water. Fe-ZT, which contains selenium, is beneficial for growing Pleurotus ostreatus mushrooms. The fungi convert inorganic Se from Fe-ZT into a more useful organically bonded form. ZT and Fe-ZT as supplements retain nitrogen and potassium in sandy, silty loam and silty clay soils. ZT shows an affinity toward toxic metal cations, which are essential for cleaning contaminated water. The adsorption of atenolol, acetylsalicylic, and salicylic acid onto M-ZT (M–Cu2+, Mn2+, Ni2+, or Zn2+) from water solutions suggests that both the natures of M and pharmaceuticals have a significant impact on the adsorption mechanism and determine the adsorption capability of the ZT. ZT is an excellent carrier for ultrafine (2–5 nm) nano oxide particles, which have been shown to have catalytic activity in different chemical processes and photodegradation reactions of organic pollutants. ZT can also be transformed into SO4-SnO2-ZT, which is catalytically active as a solid acid. M-ZT is an effective carrier of valuable bacteria. Ag-ZT possesses beneficial bactericidal activity in disinfecting water and soil remediation. [ABSTRACT FROM AUTHOR]

In this study, natural clinoptilolite was treated with HCl, HNO3, and C2H2O4 at various concentrations (0.1, 0.5, and 1.0 M) at different temperatures (60, 70, and 80 °C) and treatment times (2, 3, and 4 h). The hydrogen adsorption capacity of natural clinoptilolite increased from 0.446 to 3.255 mmol/g after treating with 0.5 M HNO3 at 80 °C for 2 h. The correlation of the newly produced textural and structural properties with hydrogen adsorption ability is explained by characterizing the modified clinoptilolites using X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and temperature programmed desorption of ammonia (NH3-TPD) measurements. The results show that the hydrogen adsorption capacity of modified clinoptilolites is associated with both the quantity and strength of the strong acid sites, in addition to the enhanced surface area and micropore volume. The hydrogen adsorption data for natural and acid-treated clinoptilolite samples at 77 K obeyed the Freundlich isotherm model. [ABSTRACT FROM AUTHOR]

In a previous study, the larger size of synthetic zeolite particles was highlighted as better choice for electrocoagulation combined with zeolite (ECZ). This choice resulted in a smaller rise in pH and temperature, a more significant decline in turbidity as well as chemical oxygen demand (COD), and lower electrode wastage, but with greater damage to the electrode surface. The focus of this study was to determine whether natural zeolite of three different particle sizes has the same effect on the ECZ process. The Taguchi method L9 was employed in planning the experiments, with particle sizes of natural zeolite ranging up to 600 μm, three different electrode materials (carbon steel, aluminium alloy, and sacrificial zinc anode), current density in the range of 0.003–0.018 A cm−2, and contact time in the range 10–30 min. The Taguchi optimisation results revealed a more significant decrease in COD and turbidity with the smallest particle size of natural zeolite used (90 µm) and with Al electrodes. Evidently, the zeolite particle size, together with the zeolite composition, had a significant influence on the reduction in COD and turbidity. Anode consumption ranged from 0.0172 to 0.6469 g, with minor cathode consumption evident on all electrode materials. Optical microscopy analysis indicated significant corrosion of the anodes, particularly with the largest natural zeolite particle size of 160–600 µm, while minor corrosion damage was also observed on the cathodes. [ABSTRACT FROM AUTHOR]

The high elastomer content of the crumb rubber powder obtained from the processing of used tires increases the interest for its valorization when modifying road bitumen in order to improve its elastic characteristics. Sulfur cross-linking of elastomer chains reduces the dispersion of the crumb rubber in the road bitumen during the modification process. A novel approach was explored, involving the partial desulfurization of rubber powder using a natural zeolitic catalyst, clinoptilolite, modified in its acid form. The catalytic desulfurization of the powder was carried out in a batch system at a temperature of 280°C for 6 hours in the presence of high aromaticity solvents. The catalysts' high acidity facilitated the conversion of rubber powder effectively, reaching a more suitable form to use in improving road bitumen. [ABSTRACT FROM AUTHOR]

Geopolymer materials can be formulated with a variety of precursors rich in aluminosilicates. However, some of these precursors, which are industrial by-products, are not widely available in the world. Therefore, there is a need to explore alternative potential precursors derived from natural sources. This study investigates the viability of using natural zeolite utilization as a part of the precursor in one-part ground granulated blast furnace slag (GGBFS)-based geopolymer mortars activated with sodium metasilicate. Geopolymer mortars were made with 0–90 wt% natural zeolite and cured at ambient and 40 ℃ temperatures. Fresh and hardened properties were evaluated. The test results showed that zeolite addition reduced the workability and setting time of the fresh mortar, significantly. Furthermore, the mechanical strength dropped with increasing zeolite content due to the microporous structure of the zeolite particles and weak reaction products. The microstructural examination showed that the mortars containing zeolite had a more porous structure compared to the pure slag mortar. Furthermore, heat-curing increased the mechanical strength in all mortars and densified the microstructure.

Petroleum fuel is the primary source of energy today. Its use often causes environmental problems, one of them SOx gas emissions. Palm fatty acid distillate (PFAD) is a by-product of crude palm oil refining and has great promise to be developed as a renewable energy source. This research investigates the effect of Ni/P catalyst ratios impregnated by activated natural zeolite as solid support to properties and performance of hydrodeoxygenation (HDO) of PFAD to green diesel. The HDO reaction was performed by varying Ni/P at a temperature of 350 °C for 2 h, and 40 bar H2 pressure. The highest conversion and selectivity of PFAD to green diesel are obtained at a ratio of NiP(2:1)/NZ0.5 catalyst.

The hierarchical zeolites were successfully prepared via oxalic acid and NaOH treatment of natural zeolite (ZA) collected from Wonosari, Indonesia. Mordenite and clinoptilolite are the main components found in the ZA, as shown in the XRD pattern of ZA. Oxalic acid, a weak organic acid, enhanced the Si/Al ratio accompanied by an increase in the acidity due to the pore opening of zeolite structure which was proven by the raising of VMicro. Further treatment using NaOH generated a more mesoporous system in the framework. The shift of asymmetric stretching of the T—O—T (T = Si or Al) group at 1300–1000 cm−1 was observed in the FTIR spectra as a consequence of the change in the Si/Al ratio after both treatments. The XRD profile of zeolites was maintained throughout the treatments. The catalytic activity of ZA improved after both treatments in terms of % of liquid fraction towards hydrocracking of castor oil. Interestingly, incorporating Ni, Cu, and Zn onto the treated ZA expanded the surface area except for the Zn metal due to the aggregation. Treated ZA with Ni incorporation exhibited the best catalytic activity because of the synergistic effect between the support and transition metal. These catalysts could be used up to three times without significant loss in the catalytic activity. [ABSTRACT FROM AUTHOR]

This study observed the formation of struvite crystals in wastewater using natural zeolite activated with Mg2+ ions. Mg2+ ions released from natural zeolite would react with PO4 3- and NH4 + ions from in wastewater to form struvite crystals. The results showed that at pH 8.5, the removal of PO4 3- and NH4 + ions was more effective using the modified zeolite than the natural zeolite. Adding 40 g/L Zeo-Mg (1) produced the best results, with PO43- (93.32%) and NH4 (40%) adsorption. Meanwhile, 40g/L ZeoMg (2) adsorbed 81% PO4 3- ions and 27.12% NH4 + ions. The eqilibrium time of all the treatments was 40 min. The results of observation through SEM, EDX, and FTIR showed that struvite crystals were formed on the zeolite surface. Kinetic models indicated that the mechanism of struvite formation on the surface of natural and modified zeolite was mainly chemisorption. Further calculations showed that the adsorption of PO4 3- and NH4 + ion followed the pseudo-first-order kinetic model. [ABSTRACT FROM AUTHOR]

Natural zeolite is a honeycomb-structured aluminosilicate mineral with an open crystalline structure which makes it suitable for a variety of applications. Given the beneficial effects of zeolites on the properties of cementitious materials, the present paper aims to summarize the recent findings reported in the scientific literature on the use of zeolites in cement-based construction materials. This paper limits the analysis to natural zeolites. The influence of natural zeolites on the workability and setting time of cement-based construction materials revealed that increasing the zeolite content led to a reduction in workability compared to the control mixes. At the same time, the initial and final setting times of cement pastes showed a decreasing trend with an increase in the replacement percentage. The slow pozzolanic reaction of clinoptilolite zeolite results in lower flexural strength and compressive strength values of mortars at the age of 28 days. Blending zeolites with other supplementary cementitious materials resulted in improved values of the mechanical properties of mortar and concrete. The findings regarding the impact of zeolite on the durability of concrete suggest that zeolite shows promise as a viable alternative to cement, with positive effects on various aspects of durability. The majority of the durability factors are interconnected. The presence of conflicting findings is particularly significant in this context, highlighting the need for a comprehensive approach to address these challenges in the future. [ABSTRACT FROM AUTHOR]

One of the ways to modify bitumen and asphalt mixture characteristics is to use recycled Crumb Rubber (CR). Although using CR improves the mechanical properties of asphalt mixtures and rheological behavior of bituminous binders, it increases binder viscosity. Warm Mix Asphalt (WMA) is a practical technology to ameliorate the disadvantage of Rubberized-Asphalt (RA) mixtures. This study aimed to investigate the effect of zeolite as a WMA additive on Hot Mix Asphalt (HMA) and RA mixtures. These modifiers' effect on the properties of asphalt mixtures and binders was studied utilizing different tests such as resilient modulus, indirect tensile fatigue, dynamic creep, moisture susceptibility (TSR and RMR), and rotational viscosity (RV). The findings indicate that the addition of zeolite and CR improved mechanical properties. 16% CR along with 6% zeolite is the optimum dosage to enhance durability. Moreover, the addition of CR to mixtures without zeolite decreased the TSR, RMR, and workability of mixtures, while zeolite increased the durability and workability of HMA and RA mixtures. The cost-effective analysis results also indicated that not only does the simultaneous proper use of zeolite and CR decreases energy consumption, but it also decreases the production cost of modified asphalt mixture. [ABSTRACT FROM AUTHOR]

Calcium stearate (CS) is effective to reduce permeability of different building materials under nonhydrostatic pressure but more actions need to be taken to shed light on its main and side effects on properties of cement‐based materials. This research project investigates the effect of CS on properties of these materials. Compressive strength analysis shows that the addition of CS at the dosage of 1% of cement weight reduces this parameter by approximately 20% but reducing water‐to‐binder ratio, and replacing 7.5% of cement weight with silica fume (SF) compensate for the strength loss caused by CS. Results of drying shrinkage test show that the addition of CS slightly increases drying shrinkage but replacing 7.5% of cement weight with SF can compensate for the negative effects of CS on drying shrinkage. Permeability analysis shows that CS is not as effective as SF and natural zeolite (NZ) to improve impermeability under hydrostatic pressure but it is more effective than SF and NZ to improve impermeability under nonhydrostatic pressure because the addition of CS at the dosage of 1% of cement weight reduces capillary water absorption by roughly 60%. Therefore, the simultaneous use of CS and these supplementary cementitious materials improves not only impermeability under hydrostatic pressure but also impermeability under nonhydrostatic pressure. [ABSTRACT FROM AUTHOR]

There is still a significant problem associated with corrosion of steel bars embedded in concrete structures as a result of simultaneous chloride ingress and carbonation. This results in a decrease in the durability and service life of reinforced concrete structures. An experimental study was conducted to investigate the effect of carbonation on the diffusion of chloride ions in concrete mixtures containing 8% silica fume and 10% natural zeolite. To accomplish this, concrete specimens with water-to-cementitious materials (w/cm) ratios of 0.40 and 0.50 were placed in a system that simulated pure carbonation, tide cycles of the marine environment, and spraying conditions separately. Carbonation results in the release of bound chlorides from concrete pores, which further facilitates chloride ingress into rebar. Additionally, the simultaneous chloride ingress and carbonation can lead to a lower carbonation progress and an increase in the chloride diffusion coefficient. Consequently, rebar corrosion increased and concrete structures were less likely to last for a long period of time. When supplementary cementitious materials (SCMs) are used in concrete mixtures, this problem may become solely important. Based on the results of the present study, it is concluded that adding 8% silica fume or 10% natural zeolite to concrete reduces its carbonation resistance while increasing its carbonation-induced corrosion resistance. Additionally, when carbonation and chloride ingress occur simultaneously, the addition of 10% natural zeolite to concrete improved its diffusion coefficient more than 8% silica fume. [ABSTRACT FROM AUTHOR]

The disposal of Iron ore tailings Powder (IP) is the primary concern for numerous steel industries. Similarly, natural zeolite, a significant by-product of volcanic eruptions, pollutes the environment to an extreme degree. This study investigates and implements the extensive use of IP and natural zeolite as admixtures in M20-grade concrete in order to address the challenges posed by IP and zeolite. By varying the admixture percentage, three distinct mix ratios were formed. First, sand was replaced by iron at concentrations of 5%, 10%, 15%, and 20%. Second, cement was replaced by zeolite at 5%, 10%, 15%, and 20%. In the final mixture, both sand and cement were substituted with iron ore powder and zeolite, respectively, at 5%, 10%, 15%, and 20%. Conplast SP 430, a water-reducing admixture, was used in all of the mixtures at 1% by weight of cement. The mechanical properties of concrete, including compressive strength, split tensile strength, and flexural strength, were studied. To evaluate the long-term properties of admixture-modified concrete, durability tests such as permeability tests, water absorption tests, rapid chloride attack tests, acid attack tests, and sulphate attack tests were conducted. In addition, slump cone tests and thermal conductivity tests were conducted on all the mix combinations to determine the changes in workability and thermal conductivity coefficient. The test results demonstrated that a mix containing 10% zeolite replaced with cement and 10% iron ore tailing powder replaced with sand has the highest performance in terms of strength and durability characteristics. The study also constructs a comparable cost estimate to ensure that its actual implementation is feasible. [ABSTRACT FROM AUTHOR]

As energy needs continue to rise in line with the use of fossil energy, which is difficult to renew, other alternative energy is needed to continue to meet current and future energy needs. One alternative energy that is easy to produce is biodiesel. One of the raw materials that is quite widely used and developed in making biodiesel is waste cooking oil. According to statistical data, Indonesia can produce waste cooking oil of 5.06 tons per year. Waste cooking oil contains free fatty acids that can be processed into biodiesel using the help of heterogeneous catalysts. One source of heterogeneous catalysts that can be used is CaO, which can be found in green shells, where the CaO contained can be taken through the calcination process of green shells. To maximize the waste cooking oil processing process, an adsorption pretreatment process can be carried out. The adsorption process is carried out to reduce the FFA levels and acid numbers contained in waste cooking oil so that the transesterification reaction process can run optimally. Natural zeolite can be used as a good adsorbent to purify and lower the acid number of waste cooking oil. This study aims to find the best operating conditions in producing biodiesel made from waste cooking oil with a pretreatment adsorption process using natural zeolite and green shell catalyst through the factorial design method, where from the results of the research carried out, it was found that the density and viscosity met the SNI, the biodiesel yield produced was 45-65% and the cetane number test on samples 3 and 7 was 34,7 and 34,2 which did not meet the SNI. The operating temperature and amount of catalyst used in the biodiesel manufacturing process produce biodiesel with good density, viscosity, and yield, namely at a temperature of 60°C and a catalyst content of 6 grams. The operating temperature of 65°C produces a smaller density because the boiling point of alcohol is 64.7°C, so the reaction process is not perfect. [ABSTRACT FROM AUTHOR]