Free Alkali Research Articles

Effect of Mixing Time Variation and Framing Time on the Quality of Coffee Grounds-based Solid Soap

The increase in public consumption of coffee has resulted in an increase in wasted coffee grounds. Coffee grounds have good content for the skin, so they can be reused as a basic ingredient in soap-making. In the soap making process, the mixing and framing stages can affect the quality of the soap. This study aims to determine the effect of mixing time of 24.5 minutes, 25 minutes, and 25.5 minutes as well as framing time of 3 days, 5 days, and 7 days on the physical and chemical quality of solid soap made from coffee grounds. The physical quality parameters observed are colour, texture, cracking, and foam power. The chemical quality parameters are foam stability, pH, moisture content, and free alkali. The method used was the questionnaire method followed by statistical analysis using the Kruskal Wallis test for physical quality tests and the experimental method followed by statistical analysis using the Two-Way ANOVA test for chemical quality tests. The results showed that all variations in mixing time and framing time had an effect on the physical and chemical quality of solid soap and there were significant differences. The panellists assessed the physical quality of the soap to be attractive, hard, with no cracks, and foamy, while the results of the chemical quality test, the soap produced is safe to use by the quality standards of solid soap with a foam stability range of 82%-97%, pH 10.3-11.8, moisture content 6%-14%, and alkali free 0.03%-0.09%.

From kitchen to cosmetics: Study on the physicochemical and antioxidant properties of waste cooking oil-derived soap

A large amount of used cooking oil (UCO) is improperly disposed of in sewage and rivers, leading to environmental pollution and posing health risks such as carcinogenic diseases. This study explores an eco-friendly approach to addressing this issue by repurposing UCO for laundry soap production, contributing to waste management and environmental decontamination. The soap was prepared by treating UCO with an alkaline solution (NaOH) through a simple saponification process, providing a greener alternative to traditional methods that rely on imported vegetable oils. The prepared soaps were evaluated for cleansing capacity as well as physical, chemical, and physicochemical properties. The results showed moisture content of 9.27 % to 10.34 %, pH ranging from 6.03 to 4.46, chloride percentage from 0.055 % to 0.29 %, free caustic alkali between 0.152 and 0.175, and total alkali content from 0.29 % to 0.73 %. These values meet the requirements of East African Standards (EAS), validating the quality of UCO-based soaps. By diverting UCO from waste streams and utilizing it in soap production, this approach supports waste management, minimizes environmental pollution, and contributes to sustainable production practices.

Pembuatan Sabun Transparan Berbasis Minyak Kelapa dengan Penambahan Ekstrak Buah Pedada (Sonneratia caseolaris) sebagai Bahan Antioksidan

Mangrove Apple (Sonneratia caseolaris) is a fruit native from tropical area that has antioxidant activity. This study aims to produce transparent soap with pedada fruit antioxidant enhancing agents and the observation of transparent soap quality in accordance with SNI 03-3532-1994 and antioxidant activity of transparent soap. Research began with pre-treatment process, namely extraction of mangrove apple enhancing agent by maceration and infundation method using methanol and water solvent. The obtained extracts were then added as variation of coconut oil soap production formula. The obtained soaps were then tested for free alkali rate, free fatty acid rate, moisture content, foam stability, pH and antioxidant activity by DPPH method. The antioxidant activity of the obtained soap shows that with the formulation by 0.5 g of methanol maceration extract of mangrove apple resulted in soap with IC50 antioxidant activity of 122.30 μg/mL.

Inhibition of efflorescence for fly ash-slag-steel slag based geopolymer: Pore network optimization and free alkali stabilization

The efflorescence problem is always an intractable problem for geopolymer. Silica fume (SF), nano-silica (NS), 5A zeolite (ZL) and nano-silica treated with silane (NST), were used to mitigate the efflorescence of fly ash (FA) - granulated blast furnace slag (GBFS) - steel slag (SS) based geopolymer. The effect of their dosages on the efflorescence was evaluated through accelerated efflorescing, leaching and unconfined compressive strength (UCS) tests. The inhibition mechanisms were explored by XRD, SEM, FTIR and MIP characterization. It revealed that SF and NS presented the most effective mitigating effect on efflorescence, with 9 % of SF and 2 % of NS totally inhibiting efflorescence and improving the compressive strength, and ZL and NST also alleviated the efflorescence at appropriate contents. Optimizing pore network and stabilizing free alkali were found to be the most important aspects for inhibiting efflorescence. The SF and NS worked efficiently in both two ways, which contained a large amount of dissolvable silicate that reacted with the excessive alkali to form C(N)-A-S-H and C-S-H gels. This filled and reduced the pores from 26 nm to less than 10 nm, and stabilized alkali with reduce the free w(Na+) by more than 50.45 %. On the other hand, ZL can solidify free alkali through the ion exchange property and fill pores due to its microaggregate nature, and NST reduced the efflorescence through blocking free alkali migration paths by hydrophobicity of the pores. These findings would guide the selection of appropriate methods to solve the efflorescence problem of geopolymers.

Manufacturing natural soap-base (Multiclean) with the addition of wuluh starfruit extraction (Averrhoa)

Starfruit extract is used as a base for making natural soap that is more environmentally friendly and beneficial for health. The aim of this study is to identify the optimal conditions for adding starfruit extract to natural soap production, which involves citric acid and surfactant components. The method involves maceration and extraction of starfruit to obtain citric acid by immersing it in 80% ethanol. The soap is produced using a hot process at temperatures between 70-80°C with three formulas: F1 (200:200:10), F2 (225:175:15), and F3 (250:150:20), representing different ratios of virgin coconut oil (VCO), olive oil, and starfruit extract, respectively. Potassium hydroxide (KOH) is used as an alkali at a concentration of 30%. After the soap is made, MES (a plant-based surfactant), sodium citrate (Na3C6H5O7) as a preservative, and sodium bicarbonate (NaHCO3) as a cleanser are added. Testing of the three soap formulas showed they all meet Indonesian National Standards (SNI). Among 20 respondents, F1 was rated the highest in terms of color, scent, and softness. It had 83% foam stability, 0.85% moisture content, a pH of 8, and 0.001% free alkali content. These results suggest that consumer preference is influenced by the starfruit extract content.

Laboratory and field investigations of alkali-silica reaction prevention by supplementary cementitious materials: Influence of the free alkali loading

Performance tests are often used to evaluate the effect of supplementary cementitious materials (SCMs) on alkali-silica reaction (ASR). However, these tests may be quite demanding, thus other approaches may be more efficient to identify the materials that are worthwhile testing further. This paper presents ASR expansion data obtained from outdoor exposure (2.5 years) and three accelerated laboratory tests: ASTM C1567, TI-B 51, and RILEM AAR-10. A reactive sand containing porous flint, which caused damage in structures after only a few years, was tested with Portland cement and a wide range of SCMs: fly ash, two biomass ashes, two calcined clays, sewage sludge ash, crushed brick, and glass beads. Expansion data were compared with free alkali loadings determined on companion paste samples. It was observed that no expansion occurred below around 2.4 kg/m3 free Na2Oeq in AAR-10 and outdoors (so far). Conversely, no clear trend was found with ASMT C1567 and TI-B 51 results, probably because the outcomes of these immersion tests depend on the transport properties of the specimens and interactions with the surrounding solutions. Since expansions in AAR-10 and outdoors correlate, the free alkali loading seems a promising parameter for screening how SCMs influence the risk of deleterious ASR.

Study on recycling and utilization of phosphogypsum and lithium slag in vertical barrier materials

Traditional vertical barrier materials typically have a large carbon footprint and high cost. Phosphogypsum (PG) and lithium slag (LS), possess latent cementitious activity. This study investigated the potential use of PG and LS in vertical barrier materials. The basic characteristics of the system were studied for LS:PG (mass ratio) ranging from 1:1–1:9, with a bentonite content of 10 % and a water-to-solid ratio of 0.5. The PG-LS matrix was microscopically characterized using XRD, TG, FT-IR, and SEM analysis. Additionally, an economic and sustainability assessment was performed. The results indicated that when LS:PG was in the range of 1:3–1:1, the flowability and setting time ranged from 16.15 to 21.00 cm and 51–87 hours, respectively. The bleeding rate within 12 hours was consistently below 5 %. Furthermore, the compressive strength and permeability coefficient at 28 days were within the ranges of 1.81–7.99 MPa and 2.91×10−8 to 7.98×10−9 cm/s, respectively. Excessive addition of PG was found to be unfavorable for the formation of C-(A)-S-H gel, resulting in an increase in free alkali content in the system and promoting the carbonation-induced formation of Calcite, thereby reducing the compressive strength and increasing the permeability. Compared to traditional barrier materials, the PG-LS-based barrier material exhibited a 61 % reduction in CO2 emissions and a cost reduction of 75–82 %. Additionally, the leaching concentrations of Zn, Cr, Ni, Cu, Pb, Cd, and As were below the standard limits. Therefore, the utilization of PG and LS in vertical barrier systems demonstrated excellent performance, economic feasibility, and environmental benefits, indicating significant potential for widespread application.

The effectiveness of adding antioxidant compounds from pedada leaves extract (Sonneratia Caseolaris) in antiseptic soap production

Pedada leaves (Sonneratia caseolaris) are plants from tropical areas with relatively high antioxidant content. This research aims to make antiseptic soap with the addition of pedada leaves and see the quality of the antiseptic soap by SNI 03-3532-1994. This research includes the pre-treatment process, namely taking pedada leaf extract by maceration using ethanol and acetone solvents using a variety of evaporation tools in the form of a water bath and soxhlet, then making soap with coconut oil with variations used in the form of evaporation methods and the amount of extract used. This research analyzed water content, free alkali, and free fatty acids. The observations showed that using a water bath would produce a more significant amount of extract. The results of the soap-free alkali analysis produced ranged from 0.061% to 0.088%, which shows that the free alkali content is still below the limit determined by SNI. The lowest water content analysis results obtained were 11.30%.

Synthesis of antioxidant liquid soap from pandan leaf extract (Pandanus amaryllifolius Roxb.) and cocamide-dea

Exposure to UV rays can form free radicals, which will cause progressive damage to the skin's cellular structure, resulting in accelerated aging. The antioxidants contained in pandan leaves can capture free radicals and reduce their adverse effects. This study aims to determine the correct formula for antioxidant liquid soap by adding pandan leaf extract. The antioxidant liquid soap formula was made using four variations of cocamide-DEA concentrations, namely 2%, 4%, 6%, and 8%, and three concentrations of pandan leaf extract (Pandanus amaryllifolius Roxb.), namely 20%, 30%, and 40%. The extract was made using the maceration method with 96% ethanol solvent. Soap formulations are tested using free alkali, fatty acid, and water content tests. The results of observations of the antioxidant liquid soap formula with pandan leaf extract and the addition of cocamide-DEA have good physical quality and stability and meet standards.

FORMULASI SEDIAAN SABUN PADAT EKSTRAK ETANOL KULIT BUAH PEPAYA (CARICA PAPAYA L.)

Papaya skin (Carica papaya L.) has antibacterial activity against Staphylococcus aureus bacteria and Escherichia coli bacteria. This research aims to find out whether papaya peel extract can be formulated into solid soap. Solid soap preparations were made in 4 formulas with F0 (formula 0) as the base and the addition of papaya peel extract at Fl (formula 1) 3.5 g, FII (formula 2) 7 g, and FIII (formula 3) 10.5 g. The formulated solid soap preparation is subjected to physical evaluation including organoleptic, pH, foam height tests, water and free alkali content. The research results showed that all formulas met the requirements except for the water and free alkali content tests which did not meet the requirements because they still exceeded the maximum limit for free water & alkali content set by SNI 2016.

Use of Jernang Fruit (Dragon's Blood) as an Additive in the Manufacture of Transparent Solid Soap for Skin Regeneration

The use of jernang fruit (Dragon's Blood) as an additional ingredient for making transparent solid soap for skin regeneration has been widely used. This research aims to determine the effect of jernang extract and NaOH used on the characteristics of the soap produced including the pH value, water content, free fatty acid value, free alkali value based on the requirements of SNI 06-3532-1994, as well as knowing the organoleptic figures and antioxidant activity. With the presence of transparent solid soap from jernang extract, it can optimize the use and use of jernang which is rarely processed in the surrounding environment and can improve the economy of the Simpang Keramat village area, Aceh Utara. Making transparent solid soap was carried out by varying the volume of jernang extract 2 ml, 4 ml, 6 ml, 8 ml, 10 ml with a volume of 30% NaOH of 20 ml, 25 ml, 30 ml, 35 ml and 40 ml.

Preparation and antimicrobial activity of solid soap from kefir cheese wastewater

All Soap made from chemicals causes side effects on the skin. making soap with natural ingredients kefir cheese wastewater whey) is safe for the skin and has antibacterial properties. The research aim was to produce solid soap-made kefir cheese wastewater, with determined physicochemical characteristics, and better antibacterial activity. The materials used in this research are cheese wastewater (whey). This research was making a kefir formula with the main ingredient of a varied concentration of whey added with turmeric. The solid soap kefir cheese whey contains olive oil, palm oil, VCO, sodium hydroxide, and variations of kefir whey. The characteristic test was conducted by determining free alkali, water content, pH, and foam height. The well diffusion method was applied to test the antibacterial activity. The results show that all formulas of solid soap from kefir cheese wastewater indicated that the quality test kefir whey meets the requirements established by SNI 3532: 2016 and ASTM-D 2002. Soap kefir whey cheese with variant dyes Curcuma Longa potential alternative to the cosmetic industry in anti-acne soap production.

Preparation of Liquid Soap Utilising Used Cooking Oil with Aloe Vera as an Antibacterial Agent

Waste cooking oil has been repurposed in the preparation of liquid hand soap, enriched with Aloe vera extract as an antibacterial agent. To ensure the safety and efficacy of the product in bacterial inhibition, comprehensive testing of physical quality and antibacterial activity has been undertaken on the produced liquid soap. The test results affirm that the soap product complies with the Indonesian National Standard for free alkali content, acidity level (pH), foam height, foam stability, and water content. Notably, the soap exhibits a free alkali content of 0.01873%, a pH of 10, a foam height of 65 mm, and a foam stability value of 84.61%. The water content in the soap is measured at 40%. These results collectively position the soap within the criteria for high-quality soap. In the antibacterial effectiveness test against Staphylococcus aureus and Escherichia coli bacteria, the addition of Aloe vera has markedly expanded the inhibitory zone, demonstrating a significant enhancement in antibacterial activity. In light of the above, this study aims to address environmental pollution and health risks associated with improper disposal of waste cooking oil. Moreover, the addition of antibacterial Aloe vera presents an economically valuable solution by repurposing waste cooking oil into a useful product.

FORMULASI DAN EVALUASI SABUN CAIR EKSTRAK ETANOL BAWANG DAYAK (Eleutherine Bulbosa (Mill.) Urb) TERHADAP BAKTERI Staphylococcus Epidermidis

Ethanol extract of dayak onion bulbs has antibacterial activity that can inhibit staphylococcus epidermidis bacteria with an inhibition zone value of 16.9 mm (strong) so that it has the potential to be developed into antibacterial liquid soap preparations. The research method uses experimental by testing the physical evaluation of liquid soap preparations which include organoleptic test, homogeneity, pH test, viscosity test, cleaning power test, foam height test, free alkali test, and stability test (Cycling Test) and antibacterial testing using the disc diffusion method. The results of the physical evaluation characteristics of dayak onion ethanol extract liquid soap meet the predetermined requirements. The results of antibacterial activity of dayak onion ethanol extract liquid soap have variations in the value of the inhibition zone category, namely at a concentration of 1% the value of the inhibition zone is 5.41 mm (weak), a concentration of 5% the value of the inhibition zone is 7.01 mm (medium), a concentration of 10% the value of the inhibition zone is 7.53 mm (medium), a concentration of 15% the value of the inhibition zone is 8.15 mm (medium) so it can be concluded thatdayak onion ethanol extract liquidsoap has potential as an antibacterial against Staphylococcus epidermidis bacteria.

Formulation of Body Odor Bacteria Inhibiting Deodorant Spray from Ethyl Acetate Extract of Klika Kesambi

Acne is one of the skin damages caused by acne-causing bacteria. Flavonoids, saponins, and tannins in taro tubers can potentially have activity against acne-causing bacteria. This study aims to determine the formulation of extract transparent solid soap preparation that meets the characteristics and assess the activity of soap preparation as anti-acne against acne-causing bacteria. Taro tubers were extracted by maceration method. The extract was formulated as transparent solid soap preparations with variations in extract concentration, namely F0 0%, F1 2%, F2 4%, and F3 8%. The soap was evaluated for characteristics including organoleptic test, pH, moisture content, free fatty acids and alkali, mineral oil test, and foam stability test. Antibacterial activity testing of transparent soap extracts was carried out against acne-causing bacteria. The extraction results obtained an extract yield of 10.86%, the three extract formulas have transparent solid soap characteristics that meet the requirements. Soap preparation formula 1 has an inhibition zone of 21.66 ± 0.31 mm against P. acnes bacteria, 19.11±0.53 mm against S. epidermidis, 21.74±0.34 mm against S. aureus. Soap preparation formula 2 has an inhibition zone of 18.53±0.26 mm against P. acnes bacteria, 18.71±0.49 mm against S. epidermidis, 20.16±0.34 mm against S.aureus and soap preparation formula 3 has an inhibition zone of 19.03±0.68 mm against P. acnes bacteria, 19.93±0.86 mm against S. epidermidis, 22.75±0.59 mm against S.aureus. In conclusion, formula 2 with 2% extract concentration has the best soap characteristics and has the most optimal inhibition zone.

Chemical characteristics of soaps obtained using red hot pepper seeds oil (Capsicum annuum L.)

Vegetable oils are an important raw material for soap production. They are widely distributed in nature, but only some of them are used in soap production. The search for alternative raw materials for oils from renewable sources is current worldwide. As a potential source of such oil, hot pepper seeds are considered. They are waste plant products that contain proteins, dietary fiber, lipids, minerals, bioactive compounds, etc. This study aimed to identify the optimal amount of hot pepper seed oil to include in the oil blend for cold process soap making. Four variations of soaps were made with hot pepper seeds oil, palm oil and coconut oil in different ratios. The values of indicators – total fatty matter content, free alkali, foaming ability, pH were determined. Soaps containing up to 10 % hot pepper seeds oil in the oil blend exhibit satisfactory quality characteristics. The findings indicate that hot pepper seeds oil is suitable for use in cold process soap making. Its proportion can be as high as 10 % of the total oils.

Optimization of Antiseptic Paper Soap through Varying NaOH Concentration: Combination of Cooking Oil, Citronella Oil, and Aloe Vera

Antiseptic paper soap is convenient because it is flexible, safe for the skin, easily foams, and relatively affordable. Measuring the ratio between the concentrations of NaOH, cooking oil, citronella oil, and aloe vera additives is needed to improve the quality of antiseptic paper soap. Testing the saponification rate, density, pH, water content, fatty acid (FA) level, and free alkali content is critical to determine the characteristics of antiseptic paper soap so that it meets the standards for solid bath soap according to SNI 3532-2021 which is closest to the characteristics of paper soap because SNI for paper soap is not yet available. The weight ratio of citronella oil to cooking oil used is 1:1, 1:2, and 1:3. The NaOH concentrations used were 30%, 40%, and 50% w/v. The natural additives used are 0%, 5%, and up to 10% of the total mass. The research results showed that saponification value of the antiseptic paper soap produced was 197.724 milligrams KOH/gram up to 206.138 milligrams KOH/gram, the pH of the antiseptic paper soap was 9.1-10.6, the water content value was 10.940%-23.863%, the alkali content value free is 0.044%-0.104%, total fatty acid (FA) content is 29.688%-45.734%. The best antiseptic paper soap is produced using 30% w/v NaOH with a weight ratio of citronella oil to cooking oil used of 1:1 and natural additives (aloe vera) 5% of the total mass.

FORMULASI DAN EVALUASI SEDIAAN FACIAL WASH EKSTRAK MIMBA (Azadirachta indica A.Juss)

Neem extract is known to have antibacterial activity against acne-causing bacteria. Neem extract is made into facial wash preparations to develop herbal plants into more modern preparations. This study aims to determine the optimal formulation from the results of the physical evaluation and hedonity test and then find out that there are differences from the results of the physical evaluation of neem extract (Azadirachta indica A.Juss) facial wash preparation. The research method used was a pre-experimental laboratory one-shot case study. Physical evaluation tests included organoleptic tests, homogeneity, pH, viscosity, free alkali, foam height/foam stability, free fatty acids and hedonity (favorability test). The results of the research on the organoleptic test obtained optimal results in formula 3 and the results of the homogeneity test obtained a homogeneous preparation. Optimal pH test results in formula 3. Optimal viscosity test results in formula 3. Free alkali test results from the three formulations did not contain free alkali. Optimal foam height/foam stability test results in formula 3. Free fatty acid test results do not meet SNI facial wash standards. The results of the hedonity test showed that formulation 3 was preferred by respondents. The optimal facial wash preparation is formulation 3.

Simultaneous dealkalization of red mud and recovery of valuable metals by a novel marine fungus tolerating high alkalinity and salinity

Red mud is a highly saline and alkaline solid waste generated in alumina refinery, which entails dealkalization for safe disposal and valorization. Herein, Trichocomaceae sp. K-2, a novel fungus isolated from marine sediment, was used for the simultaneous dealkalization of red mud and recovery of valuable metals. The fungus demonstrated robust growth at high salinity (45 g/L NaCl), good tolerance to high pH (up to 12), and capability of utilizing low-cost substrates derived from lignocellulosic biomass. Both structural and free alkali can be removed by Trichocomaceae sp. K-2 to achieve a significantly lower minimum pH (<4) in a considerably short timeframe (<16 days), and the alkali removal efficiency as high as 94% was attained. Moreover, concomitant leaching of valuable Nd, Sc and Y from red mud during dealkalization was feasible. Physical disintegration and chemical erosion by the secreted organic acids were responsible for the effective dealkalization, as well as leaching of valuable metals. This study sheds lights on how marine microorganisms can be harnessed to the green disposal of red mud, and provokes the exploration of more robust and versatile marine microbes for the sustainable and cost-effective management of other highly saline and alkaline solid waste.

Ecological restoration affects the dynamic response of alkaline minerals dissolution in bauxite residue

Regulating alkalinity is the key process to eliminating environmental risk and implementing sustainable management of bauxite residue. Nevertheless, continuous release of free alkali from the solid phase (mainly sodalite and cancrinite) is a major challenge for long-term stability of alkalinity in amended bauxite residue. In order to understand the dissolution behavior of sodalite and cancrinite, their dissolution kinetics under simulated pH conditions of 8, 9 and 10 were investigated. Additionally, PHREEQC software and shrinking core model (SCM) were employed to analyze the release pattern of saline ions. The results revealed that the ratio of Na/Si and Na/Al values exhibited greater stability in sodalite than in cancrinite. The dissolution of elemental Na, Si, and Al in sodalite and cancrinite was matched with non-chemometric characteristics. The kinetic calculations by the shrinking core model (SCM) suggested that both sodalite and cancrinite exhibited slow dissolution kinetics, and their dissolution processes belong to internal diffusion control and external diffusion control, respectively. pH controlled the dissolution kinetic rates of sodalite and cancrinite mainly by changing their coupled dissolution-precipitation processes. More importantly, these findings can predict the change of alkaline components accurately, thus facilitating the implementation of efficient alkalinity regulation strategies for the ecological restoration of bauxite residue disposal areas.