Water Absorption Tests Research Articles

Evaluation of the interaction effect on viscoelastic and moisture behaviour of high-density polyethylene reinforced with multi-walled carbon nanotube and tungsten disulphide hybrid composites

This study examines the influence of varying weight percentages (wt.%) of the solid lubricant, tungsten disulphide (WS2), on the viscoelastic properties and interaction effects of a high-density polyethylene (HDPE) composite that is reinforced with both multi-walled carbon nanotubes (MWCNTs) and WS2. The fabrication of HDPE composites involved the utilisation of a twin screw extruder method to incorporate lubricants and reinforcement. The lubricant was introduced in three different proportions of 2, 4 and 8 wt.% while the MWCNT was reinforced at a constant 1 wt.% for all composite materials. The specimens were fabricated utilising an injection moulding machine. The composite's interaction effects were investigated using the Fourier transform infrared spectroscopy and Raman spectroscopy. The viscoelastic behaviours of the composite were studied using dynamic mechanical analyser (DMA). Composite moister characteristics were analysed using water contact angle measurement and water absorption test. The DMA results indicated that the HC1W2 (HDPE + MWCNT 1 wt.% + WS2 2 wt.%) hybrid composite exhibited enhanced interaction effects and desirable viscoelastic behaviour, as evidenced by loss modulus (G″) and storage modulus (G′) values. HC1W8 (HDPE + MWCNT 1wt.% + WS2 8 wt.%) sample shows less moister absorption, because adding filler improves the sample's hydrophobicity. The composite exhibits significant particle agglomeration when the lubricant content exceeds 2 wt.%. It affects the uniform dispersion of WS2 particles in the matrix, which leads to reduced composite performance.

The effect of glow discharge air plasma surface treatment on mechanical properties of natural fiber reinforced-epoxy sustainable biocomposites

ABSTRACT Natural fiber composites are widely explored sustainable alternative to conventional composites in many applications. However, since they are weak compared to conventional composites, various surface treatments are adopted to improve their overall mechanical properties. The effect of glow discharge air plasma treatment of banana and pineapple leaf (PALF) natural fibers is investigated and presented in this study. Fibres were treated for different time periods, their surface were analysed, and composite laminates with standalone and hybrid were fabricated. Tensile, flexural and impact tests in different combinations of reinforcements were carried out. Spectroscopic, thermal and microscopic characterisations like Fourier-transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), Thermogravimetric analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM) were used to study the fibre surface, 3D digital microscope was used to study the fractography and a water absorption test was carried out to study the hydrophilicity were carried out to characterise the fibre surface and the laminates. Significant variations in thermal stability and improvements in tensile strength (even up to 275%) and flexural properties were observed. This investigation revealed the cause of the same was due to the enhancement in crystallinity, mechanical interlocking and improved fibre-matrix adhesion, which was evident from characterizations.

Investigation of the Mechanical, Thermal, and Morphological Properties of ABS Composite Reinforced With Bentonite and DEHPA‐Modified Bentonite

ABSTRACTThis study investigates the mechanical, thermal, and surface characteristics of acrylonitrile–butadiene–styrene (ABS) composites reinforced with bentonite and bis(2‐ethylhexyl) phosphate (DEHPA)‐modified bentonite. The addition of bentonite significantly reduced the tensile strength and elongation at break due to the filler's inherent brittleness. Pure ABS exhibited a tensile strength of 42.2 MPa, which decreased by 16.1% with the incorporation of 20% bentonite (ABS1). Impact strength tests showed that the inclusion of bentonite lowered impact resistance, particularly in notched samples. Bentonite also increased the hardness and density, reflecting improved rigidity but reduced flexibility. Surface gloss changed from semigloss to matte, and FT‐IR spectroscopy confirmed the successful integration of bentonite. Water absorption tests revealed that DEHPA‐modified bentonite composites had higher absorption over time, highlighting the modification's effect on hydrophilicity. While bentonite improves certain properties, the balance between mechanical strength and flexibility needs to be further explored to meet the requirements of specific applications such as automotive components, electronics casings, and construction materials.

Biodegradable Plastics from Marine Biomass: A Solution to Marine Plastic Pollution

The growing demand for plastics has raised environmental concerns due to their non-biodegradable nature. Sustainable solutions are urgently required to decrease plastic pollution. This study explored the potential of Sargassum wightii, a seaweed found in Malaysia, as a sustainable material for bioplastic films. The seaweed-based bioplastic was produced using an extraction-based method where alginate was formed using NaOH, followed by mixing sodium alginate with isopropanol and potato starch. The bioplastic was then characterized using various analytical techniques, including Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier-Transform Infrared (FTIR) spectroscopy. Physical properties such as density and moisture content, along with environmental tests like water absorption and biodegradability, were evaluated. TGA analysis indicated that 31.12% of the sample remained as residue. FTIR spectroscopy identified the presence of bioactive compounds, with a prominent alcohol group peak at 3358cm-1. XRD analysis revealed a peak at 23.1°, indicating crystallinity within the sample. The moisture content of the bioplastic film was found to be 21.16%. The water absorption test demonstrated the film's hydrophilic nature, showing a 60% increase in weight. A soil burial test for biodegradability confirmed a 40% reduction in weight over 21 days, indicating a reasonable degradation rate. These findings suggest that seaweed holds promise as an alternative raw material for bioplastic production, contributing to more sustainable materials and reducing reliance on non-biodegradable plastics.

Evaluation of whey protein for modifying urea-formaldehyde in medium-density fiberboard (MDF) production

ABSTRACT During the cheese-making process, a protein-rich solution becomes a by-product. When released into nature, it damages the ecosystem and harms the environment. This waste material, named “whey,” is a renewable resource. This study aimed to use the whey protein to modify urea-formaldehyde (UF) adhesive for medium-density fiberboard (MDF) production. Concentrated (CWP) and isolated (IWP) whey proteins were selected, along with different combinations of lignocellulosic fibers: mostly hardwood (HBF), mostly softwood (SBF), and pure hardwood (PHw). Some physical and mechanical properties and formaldehyde emission values of produced panelswere determined. The best result for the 24-hour water absorption test was determined with a value of 35% with 10% IWP and PHw. The highest tensile strength (0.8 N/mm2), bending strength, and modulus of elasticity were obtained from boards produced with 10% IWP. It was determined that the free formaldehyde emission value obtained from the panel groups produced with WP and IWP was higher than that produced with standard UF. As a result, whey protein should be evaluated for modifying the UF adhesives and should get some satisfactory MDF properties. More research should be done to improve the formaldehyde emission values of the MDF panels produced with CWP/IWP-modified UF resin.

Determining Moisture Condition of External Thermal Insulation Composite System (ETICS) of an Existing Building

ETICS is a popular external wall insulation system, which is not without possible defects and damages. A frequent cause, direct or indirect, of damage to buildings is the impact of water (moisture). This article presents, among others, the results of tests of the moisture content of ETICS layers, the water absorption and capillary absorption of the render by means of the Karsten tube method, numerical thermo-moisture simulations, and tests of interlayer adhesion, in sample residential buildings. Mass moisture content testing of the wall substrate showed acceptable moisture levels (1–4%m) within masonry walls made of silicate blocks, as well as locally elevated moisture levels (4–8%m) in the case of reinforced concrete walls. Moisture testing of the insulation samples showed a predominantly dry condition, and testing of the reinforcement layer showed an acceptable level of moisture. Severe moisture was found in the sample taken in the ground-floor zone at the interface between mineral wool and EPS-P insulation underneath the reinforced layer. Capillary water absorption tests helped classify silicone render as an impermeable and surface hydrophobic coating. Tests of the water absorption of the facade plaster showed that the value declared by the manufacturer (<0.5 kg/m2) was mostly met (not in the ground-floor zone). The simulation calculations gave information that there was no continuous increase in condensation during the assumed analysis time (the influence of interstitial condensation on the observed anomalies was excluded). The tests carried out indicated the occurrence of numerous errors in the implementation of insulation works affecting the moisture content and durability of external partitions.

Chitosan-Coated Alginate Matrices with Protein-Based Biostimulants: A Controlled-Release System for Sustainable Agriculture

Developing biodegradable complex fertilizers is crucial for sustainable agriculture to reduce the environmental impact of mineral fertilizers and enhance soil quality. This study evaluated chitosan-based hydrogel coatings for sodium alginate matrices encapsulating amino acid hydrolysates from mealworm larvae, known for their plant growth-promoting properties. The research aims to identify the potential of biopolymer matrices for producing biodegradable slow-release fertilizers and to outline future development pathways necessary for this technology to be usable in the fertilizer industry. Chitosan coatings prepared with citric acid and crosslinked with ascorbic acid optimized plant growth, while those using acetic acid negatively affected it. Water absorption and nutrient release tests showed that chitosan coatings reduced water uptake and slowed initial nutrient release compared to uncoated samples. Leaching assays confirmed controlled-release behavior, with an initial burst followed by stability, driven by alginate–chitosan interactions and ion exchange. The X-ray diffraction (XRD) analysis revealed that adding hydrolysate and chitosan increased amorphousness and reduced porosity, improving structural properties. Thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) spectroscopy demonstrated enhanced homogeneity and the presence of chemical interactions, which led to improvements in the material’s thermal stability and chemical characteristics. Biodegradation tests indicated greater durability of chitosan-coated composites, although hydrolysate incorporation accelerated decomposition due to its acidic pH. Germination tests confirmed no phytotoxicity and highlighted the potential of biopolymeric matrices for slow nutrient release. These findings indicate the possibilities of chitosan-coated alginate matrices as sustainable fertilizers, emphasizing the importance of adjusting coating composition and hydrolysate pH for enhanced efficacy and environmental benefits. The main recommendation for future research focuses on optimizing the chitosan coating process by exploring whether adding hydrolysate to the chitosan solution can reduce diffusional losses. Additionally, investigating the use of glycerol in the alginate matrix to minimize pore size and subsequent losses during coating is suggested. Future studies should prioritize analyzing percentage losses during the crosslinking of the alginate matrix, chitosan coating, and final shell crosslinking. This pioneering research highlights the potential for encapsulating liquid fertilizers in biopolymer matrices, offering promising applications in modern sustainable agriculture, which has not been studied in other publications.

Experimental Investigation of Durability Properties of Polymer Coated Pumice Aggregate Lightweight Concretes.

Pumice aggregates with low density and high porosity are widely used in lightweight concrete. The high water retention ability of pumice aggregates adversely affects the properties of fresh concrete. Additionally, pumice aggregates' inadequate mechanical strength and durability hinder concrete performance. In recent years, research on coated aggregates has gained traction to improve the physical properties, mechanical strength, and durability characteristics of concrete. In this study, coarse pumice aggregates were coated with polyester and partially substituted with uncoated aggregates at ratios of 0%, 25%, 50%, 75%, and 100% in lightweight concrete formulations. Specific weight and water absorption tests were performed on the aggregates, while slump and unit weight tests were performed on fresh concrete mixtures. SEM-EDX analyses, unit weight, water absorbing capacity, sorptivity, compressive strength, freeze-thaw resistance, and sulfate resistance tests were performed on concrete specimens. The results indicated that the polyester coating significantly increased the specific weight of the aggregates and decreased the water absorption rates by up to 85%. Despite the coated aggregates resulting in decreased compressive strength of concrete specimens, they demonstrated reduced water absorbing capacity and sorptivity characteristics relative to reference concrete. Moreover, concrete made with coated aggregates exhibited better results in freeze-thaw and sulphate resistance tests.

A Taguchi-based study on the control factors of reinforced composites with the fiber of coir and pineapple leaves.

The use of composite materials, whether metallic or non-metallic, is becoming more popular nowadays because of some of their superior characteristics compared to the use of wood and metallic materials alone. From this perspective, a new natural fiber reinforced composite by varying the fiber orientation was developed in this study using coir and pineapple leaf fiber. This work uses the Taguchi method to investigate the different effects of control factors on mechanical and physical characteristics of the fabricated natural fiber-based composites. Various control factors were used, including fiber ratios, angles of orientation, and mat types. The testing was conducted in accordance with ASTM standards, and the results were validated through various statistical analyses including Taguchi orthogonal array analysis, confirmation tests, regression analysis, and analysis of variance (ANOVA). Based on the analysis and validation, the highest mean impact strength was found 53.93J/cm2, tensile strength 31.94MPa, flexural strength 46.365MPa, Rockwell hardness number 77, and lower water absorption rate only 3.62%. From the confirmation test, margin of errors was found to be 4.84%, 2.59%, 2.35%, 6.62%, and 2.334% for impact, tensile, and flexural strength, Rockwell hardness, and water absorption test respectively. The variation of the experimental and predicted results was observed from the regression analysis, and it was 2.93 to 0.4J/cm2, 2.12 to 0.79MPa, 3.54 to 0.33MPa, 2.33 to 0.8 RHN, and 0.92%-0.13% for impact, tensile, and flexural strength, Rockwell hardness, and water absorption test respectively. Overall, ANOVA analysis was used to examine the effects of different control variables, and it was discovered that the angle of orientation of fibers had a substantial impact on flexural strength and water absorption rate were 72.30% and 70.89% respectively. Similarly, mat types on tensile strength and Rockwell hardness with 46.47% and 50.67% respectively. In addition, the impact strength was most significantly affected by the wt.% ratio of fibers, which was approximately 50.32%. From the above characteristics and their environmentally friendly behavior, these composites can be used in the place of synthetic fiber-based products.

Efeito da cura por carbonatação e do teor de sódio em geopolímeros submetidos ao ataque por sulfatos de sódio e magnésio

Abstract Geopolymer cement stands as an alternative to Portland cement to reduce the impacts associated with its production. This material is also affected by ions that can damage its mechanical properties and reduce its durability. Therefore, this research aims to evaluate metakaolin geopolymer concretes attacked by sulfates, both sodium and magnesium. The samples were made by varying the sodium oxide (Na2O) content in the activators on the metakaolin, the curing type, and the water/metakaolin ratio. The specimens were exposed to sodium sulfate, magnesium sulfate, and reference solutions (water) for 10 weeks. The analyses were performed using water absorption (by capillarity and immersion) and compressive strength tests. The results showed that sodium sulfate attack was more aggressive than magnesium sulfate in geopolymer concretes, 91.67% of the samples submitted to sodium sulfate degraded during absorptions tests while 8.33% were degraded by magnesium sulfate. A sodium content of 22% in metakaolin achieved greater resistance to magnesium sulfate attack and curing by carbonation did not improve the properties of the mixtures.

Development of Particle Board Biocomposite From Coffee Skin and Tofu Dregs With Polyethylene Plastic Adhesive As Furniture Interior

The need for particle board interiors is still in great demand to be used as wood-sourced interiors. In line with this, currently the problem of waste is still a fairly complex problem, both organic and inorganic waste. Coffee rinds and tofu pulp are organic wastes that have not been optimally utilized. Therefore, research was conducted on the manufacture of particleboard from coffee rinds and tofu pulp with PP plastic adhesive which aims to reduce the rate of deforestation due to tree felling as raw material for interior manufacturing and to control the environment by utilizing waste in the community into functional products. This study aims to determine the best formulation of particleboard made from Polyethylene plastic, coffee bean hulls and tofu pulp. Tofu dregs need to be preserved by soaking the dregs for 48 hours in a 5% glycerol solution and 15% NaCl solution in a 50:50 ratio. Then soaked for 48 hours. soaking 15.121%. To determine a good particleboard formulation, a physical evaluation of the particleboard was carried out including particleboard density test, water absorption test, moisture content test, thickness development test and instrumentation testing using SEM to see the surface structure of the particleboard. Based on the results of physical testing, the best formulation of particleboard biocomposites was obtained, namely the ratio of 70:30 (% w/b) (70% of tofu pulp and coffee bean skin and 30% of PET plastic) which is in accordance with SNI 03-2105-2006 standards. Biocomposite particleboard formulation 70:30 (% w/b) has a density of 0.60186 gr/cm3, water absorption of 95.395%, moisture content of 2.248% and an increase in thickness after soaking of 15.121%.

Pemanfaatan Abu Sekam Padi dan Abu Boiler Kelapa Sawit Sebagai Pengganti Parsial Semen pada Pencampuran Paving Block

Plantations in Indonesia are vast and numerous. Various types of plantation products are produced every year; examples of plantations are oil palm and rice husk. These two plantations have their waste during the process of becoming finished materials. Examples of these two wastes are oil palm boiler ash and rice husks. These two wastes can be used as a partial substitute for cement because they have several compounds similar to cement. This study used the two wastes as a partial replacement for the cement used to manufacture environmentally friendly paving blocks. This study used substitution variations of 0%, 2%, 4%, 6%, and 8% with a FAS value 0.4. The tests that are used are compressive strength tests and water absorption tests. The optimum compressive strength results in each variation is 0%=25,17 Mpa, 2%=25,88 Mpa, 4%=25,93 Mpa, 6%=26,35 Mpa, and 8%=25,35%. For the optimum results of absorption in each variation is 0% = 3.52%, 2% = 2.41%, 4%= 3.50%, 6% = 4.70%, and 8% = 4.27%. According to SNI 03-0691-1996, it can be categorized as a quality B paving block for parking use. The conclusion is that adding the two wastes can increase the compressive strength until it reaches the optimum point of 6%; meanwhile, for the water absorption capacity, the variation increase can be increased because of the water absorption on the paving block.

Pengaruh Penambahan Abu Tempurung Kelapa dan Serbuk Cangkang Telur Terhadap Kuat Tekan dan Daya Serap Paving Block

Egg production, which increases yearly, produces large amounts of eggshell waste. Meanwhile, the coconut shell waste is also underutilized and piling up. Eggshell contains calcium carbonate (CaCO3), which is used as a cement composition material. Coconut shell ash contains silica, also used as a composition material for cement. The use of waste eggshell powder and coconut shell ash as a partial substitute for cement in the manufacturing of paving blocks is a solution to reduce waste and greenhouse gas (CO2) emissions during the cement production process. This study aimed to determine the percentage composition of eggshell powder and coconut shell ash that was suitable for producing paving blocks with optimal characteristics and to assess the effect of adding coconut shell ash with variations (0% ATK : 0% SCT); (6% ATK: 2,5% SCT); (3% ATK: 5% SCT); (6% ATK: 5% SCT); (3% ATK: 2,5% SCT) amount of cement, regarding the water absorption and compressive strength testing of paving blocks. The sample was 30 test objects. The experimental method used was a brick-shaped paving block with dimensions of up to 21 cm x 10,5 cm x 6 cm, referring to SNI 03-0691-1996, and testing was carried out after 21 days of age. The research results on the compressive strength of paving blocks with Quality B, the average compressive strength value is 20 MPa.

Pengaruh Penambahan Gliserol dan Kaolin serta Variabel Suhu pada Pembuatan Bioplastik dari Kulit Pisang Raja

Bioplastic is a kind of plastic made from natural polymers such as starch with a mixture of plasticizers and fillers. Banana peel (Musa paradisiaca L) can be used as a source of starch because it contains high starch, which is approximately 80%. This study was aimed to determine the effect of variations in glycerol concentration, kaolin concentration, and stirring temperature on the characteristics of the bioplastic, where glycerol and kaolin act as plasticizers and fillers. The experiment was conducted by mixing raw materials in the form of banana peel powder, glycerol, and kaolin. The concentrations of glycerol and kaolin were varied at 5%; 10%; 15%; 20%; 25% v/w starch, and 5%; 10%; 15%; 20%; 25% w/w starch, respectively, until bioplastic with optimum mechanical properties was obtained. Furthermore, the experiment was continued with temperature variations of 65°C; 70°C; 75°C; 80°C; and 85°C. The quality of bioplastics was examined through the thickness, tensile strength, elongation percentage, water absorption, biodegradation, and FTIR tests. Optimum results were obtained in bioplastics with a glycerol concentration, kaolin concentration, and stirring temperature of 20%, 15%, and 75oC, respectively. The relatively best bioplastics yielded had characteristics of a thickness of 0.084 mm, tensile strength of 13.047 MPa, elongation of 13.13%, and water absorption of 3.56%. These results have met Indonesia's national standards for bioplastics.

Estudos das propriedades mecânicas, físicas e morfológicas em compósitos utilizados na construção civil

The search for sustainable materials in the construction sector is crucial due to its significant environmental impact. Composite material technology emerges as a solution but faces technological challenges in formulating and stabilizing mixtures to minimize environmental impact. This study investigated the environmental behavior of composites made from recycled wood and plastic materials directly sourced from the industry. Three compositions were tested: 100% recycled plastics, 70% recycled wood and 30% recycled plastic, and 70% recycled wood and 30% virgin PVC. After machining to comply with mechanical testing standards, the materials underwent tensile and impact tests. Statistical analyses identified the most resistant samples for civil construction applications. Morphological analysis revealed voids and agglomerates in the compositions, as well as the distribution and compatibility of the filler materials. The water absorption test determined that the composition made entirely of recycled plastics performed best due to its hydrophobic nature, in terms of mechanical, physical, and morphological parameters. This study highlights the feasibility of sustainable composites in construction and the importance of proper material selection to achieve the desired properties.

Crack Sealing in Concrete with Biogrout: Sustainable Approach to Enhancing Mechanical Strength and Water Resistance.

Concrete, as the most widely used construction material globally, is prone to cracking under the influence of external factors such as mechanical loads, temperature fluctuations, chemical corrosion, and freeze-thaw cycles. Traditional concrete crack repair methods, such as epoxy resins and polymer mortars, often suffer from a limited permeability, poor compatibility with substrates, and insufficient long-term durability. Microbial biogrouting technology, leveraging microbial-induced calcium carbonate precipitation (MICP), has emerged as a promising alternative for crack sealing. This study aimed to explore the potential of Bacillus pasteurii for repairing concrete cracks to enhance compressive strength and permeability performance post-repair. Experiments were conducted to evaluate the bacterial growth cycle and urease activity under varying concentrations of Ca2+. The results indicated that the optimal time for crack repair occurred 24-36 h after bacterial cultivation. Additionally, the study revealed an inhibitory effect of high calcium ion concentrations on urease activity, with the optimal concentration identified as 1 mol/L. Compressive strength and water absorption tests were performed on repaired concrete specimens. The compressive strength of specimens with cracks of varying dimensions improved by 4.01-11.4% post-repair, with the highest improvement observed for specimens with 1 mm wide and 10 mm deep cracks, reaching an increase of 11.4%. In the water absorption tests conducted over 24 h, the average mass water absorption rate decreased by 31.36% for specimens with 0.5 mm cracks, 29.06% for 1 mm cracks, 27.9% for 2 mm cracks, and 28.2% for 3 mm cracks. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the formation of dense calcium carbonate precipitates, with the SEM-EDS results identifying calcite and vaterite as the predominant self-healing products. This study underscores the potential of MICP-based microbial biogrouting as a sustainable and effective solution for enhancing the mechanical and durability properties of repaired concrete.

Improving Cotton Fabric Dyeability by Oxygen Plasma Surface Activation

This paper focuses on investigating the use of low-pressure oxygen plasma as a surface treatment aimed at enhancing the wettability and dyeability of cotton fabrics for use in textiles and footwear materials. Plasma activation modified the cotton fabric surfaces, increasing their affinity for polar liquids. The research thoroughly characterised the treated fabrics through a combination of analytical methods and physical testing. Plasma treatment was performed using a 13.56 MHz RF generator at 90 W power, with an oxygen flow rate of 500 sccm and a pressure of 0.30 mbar, for treatment durations of 30, 60, and 120 s. Changes in surface chemistry were analysed with XPS, while SEM was used to observe morphological changes. Static water contact angle measurements confirmed a reduction from 128.5° in untreated cotton to 25.6° in samples treated for 30 s, indicating a significant increase in hydrophilicity. Water absorption tests showed a maximum absorption capacity of 119.6% after 60 min for plasma-treated samples, compared to 65.7% for untreated cotton. Contact angle measurements verified that surface hydrophilicity increased following the treatment. Furthermore, physical tests, such as rub fastness, colourimetry, and water absorption, were carried out to evaluate improvements in wettability, dyeability, and overall performance. The results showed notable enhancements in the wetting properties of cotton textiles, enabling better absorption of water and dyes, along with improved fixation. The comprehensive characterisations provided insights into the mechanisms behind these improvements. This research offers a sustainable approach for the textile industry, as plasma technology is a dry process that enhances dyeing efficiency while maintaining fabric performance and lowering environmental impact.

Morphology Analysis on Metakaolin/Dolomite Geopolymer under High Temperature Exposure

This paper presents the morphology of the metakaolin/dolomite geopolymer after being exposed to high temperature and compare the findings with the morphology that has not been exposed to the temperature. The geopolymers were exposed at temperatures from 200°C up to 800°C. The geopolymer was a constant mix of 90% metakaolin and 10% dolomite with 10 NaOH molarity, 0.8 solid to liquid ratio, and 2.0 by mass of alkaline activator. The morphology of geopolymer exposed to high temperature contains many pores and as the temperature rises, the pores become huge, and a higher quantity of pores can be observed. The surface analysis, compressive strength, and water absorption test were also done to support the findings. The compressive strength calculation was based on weight loss. The lowest compressive strength loss was at 200°C temperature exposure with 10.98%. Meanwhile, the highest compressive strength loss was at 800°C temperature exposure with 48.54%. In comparison, this metakaolin/dolomite geopolymer archive better properties compared to the concrete and metakaolin past studies.

ANALYSIS OF WATER ABSORPTION AND TOTAL CHROME LEACHING TEST USING ATOMIC ABSORPTION SPECTROPHOTOMETER (AAS) ON PAVING BLOCK SAMPLES MADE FROM WASTE LEATHER SHAVING

Shaving waste from leather tanning can be utilized as a filler material in the production of concrete blocks. The manufactured concrete blocks are subsequently subjected to immersion for durations of 1, 3, 7, 10, and 14 days. Subsequently, the leached total chromium content from the soaked concrete blocks is tested using an atomic absorption spectrophotometer, by the Indonesian National Standard (SNI) 6989-84:2019, which outlines the procedure for testing dissolved and total metal content through atomic absorption spectrometry. Additionally, water absorption testing is conducted according to SNI 03-0349:1989 for concrete blocks used in wall construction. The aim of this research is twofold: to determine the water absorption capacity of three sample variations and compare the results against the SNI, and to ascertain the leached chromium concentration from the soaked blocks over a time range of 1 to 14 days, using an atomic absorption spectrometer and referring to the established environmental quality standards. The results obtained from testing the total chromium content released from the soaked concrete blocks meet the requirements of the quality standards for chromium content in leather tanning wastewater, as specified in Ministerial Regulation No. 5 of 2014 (maximum of 0.6 mg/L) and Local Regulation of Yogyakarta Special Region No. 7 of 2016 (maximum of 0.5 mg/L). Meanwhile, the water absorption testing outcomes for the concrete block samples derived from shaving waste comply with the stipulations of SNI 03-0349:1989. Sample codes A and B meet the criteria for quality level 1, with a maximum absorption of 25%, while sample code C meets quality level II standards.

The Effects of Foaming Agent and Surfactant on Alkali Activated Materials as an Adsorbent for Lead Ions Adsorption

Lead, a hazardous environmental metal, has been widely used in various applications, either pure or alloyed with other metals. This study investigates the impact of foaming agents and surfactants content on the physical properties of metakaolin-based alkali activated materials. Additionally, it seeks to assess the effectiveness of metakaolin-based AAM adsorbent in removing lead ions. The research uses varying percentages of foaming agents (1 wt.%, 1.25 wt.%, and 1.5 wt.%) and surfactants (1 wt.%, 3 wt.%, and 5 wt.%). Water absorption, density and porosity tests were used to evaluate the metakaolin-based alkali activated adsorbent’s physical properties. Scanning Electron Microscopy (SEM) was used to study the morphology of the adsorbent. In addition, the adsorption test was investigated to determine the lead ion removal in the AAM adsorbent. The ion removal performance of metakaolin based alkali activated materials was evaluated based on different amounts of foaming agent and surfactant. A lead (II) solution was prepared in distilled water and used in the adsorption test. An adsorption test was carried out to determine the effectiveness of AAM with a foaming agent and surfactant, which showed that it could be suited to many harsh conditions. This study successfully identified the optimal parameters for achieving maximum efficiency in lead ion removal, featuring a concentration of 1.25 wt.% of foaming agent and 3 wt.% of surfactants. These findings hold significant promise for the advancement of effective adsorbents, particularly in the realm of wastewater treatment processes.