Communications in Science and Technology 10.
52Ae58
COMMUNICATIONS IN
SCIENCE AND TECHNOLOGY
Homepage: cst.
Microwave-assisted extraction of eco-friendly surfactant from Jatropha curcas for sustainable solubilization of reactive dyes Nita Aryanti*.
LuAoluatul Khoiriyah.
Aininu Nafiunisa.
Ratnawati.
I Nyoman Widiasa.
Abdurohman Zakki.
Alifia Rizki Adina Department of Chemical Engineering.
Faculty of Engineering.
Universitas Diponegoro.
Semarang 50275.
Indonesia Article history:
Received: 9 January 2025 / Received in revised form: 17 March 2025 / Accepted: 22 April 2025 Abstract Natural surfactants derived from plant-based sources, such as saponins, remain underexplored.
This study developed the extraction of saponins from Jatropha curcas leaves using microwave-assisted extraction (MAE) finding that the optimized condition of 3 min, 363.
15 K, 30 mL/g ratio of extraction yielded the highest saponin content of 35.
04 mg/g.
The FTIR and HPLC analyses confirmed the structural similarity between the extract and commercial saponin.
Additionally, the extracted saponins effectively solubilized Remazol Red RB and Blue TQ with solubilization efficiency increasing proportionally to the surfactant concentration.
The surfactant properties of the extracted saponin were also confirmed by its ability to form foam and high critical micellar concentration, which revealed the potential for material valorization.
This work demonstrated that the development of plant-based surfactants provides a sustainable alternative to synthetic surfactants.
Moreover, valorizing natural materials contributes to the advancement of eco-friendly technologies, particularly in waste treatment and water purification applications.
Keywords: Natural surfactant.
critical micelle concentration.
surfactant micelles.
microwave-assisted extraction Introduction Surfactants is the main component of detergents, which has an amphiphilic nature.
They have been used in many industries such as in oil recovery, emulsification, or as cleaner, wetting agents, and more .
However, most commercially available surfactants, like Tween 80 and SDS, are synthetic.
Even though synthetic surfactants is economical, it poses a serious environmental challenges, including its hazard for the soil, water and human body if being consumed.
It, as a consequence, has made their widespread application limited .
Ongoing research, in response, aims to identify environmentally friendly surfactants derived from natural Natural surfactants obtained from plants are highly desirable for being less toxic, biodegradable, and having greater specificity compared to synthetic alternatives .
These surfactants can be extracted from various sources, including animals, microorganisms, and plant parts .
eed, fruits, leaves, or flower.
, such as in the plant of Jatropha .
Belonging to the Euphorbiaceae family.
Jatropha curcas is one of the primary sources of saponins.
Commonly known as physic nut, purging nut, or pig nut.
Jatropha curcas is widely cultivated in * Corresponding author.
Email: nita.
aryanti@che.
https://doi.
org/10.
21924/cst.
Indonesia and not classified as a food crop .
Extracting saponins from Jatropha curcas requires an efficient extraction process as several factors determine the extraction yield, including solvent type, solvent concentration, solvent-to-feed ratio, irradiation temperature, extraction duration, and extraction technique .
Maceration is a traditional method used to extract non-volatile compounds by immersing raw materials into a solvent.
This technique, however, has several drawbacks, such as long extraction times, high solvent consumption, low extraction efficiency, and a high content of inert materials .
To address these limitations, modern extraction techniques have been developed to enhance process efficiency, reduce extraction time, increase bioactive compound yields, and minimize energy and solvent A number of assisted extraction technologies, such as ultrasound, high pressure, and microwaves, offer an improved performance through process intensification mechanisms .
Microwave-assisted extraction (MAE) enhances the extraction process by generating heat through microwave radiation, resulting in more rapid energy transfer and uniform This technique offers several advantages, including higher extraction yields, reduced processing time, minimal solvent usage, and cost-effective production of high-quality extracts .
Ae.
Additionally, using water as a solvent in MAE aligns with the principles of green chemistry .
This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.
0 license Aryanti et al.
/ Communications in Science and Technology 10.
52Ae58 Previous studies have primarily focused on the extraction processes and phytochemical properties of natural surfactants derived from plant-based materials .
Ae.
However, only a few studies have explored the application of plant-derived surfactants as solubilizing agents.
The only study found is when saponin from Sapindus mukorossi was applied to solubilize methyl blue and eosin yellow .
, and saponins from Sapindus rarak was used for solubilizing water pollutants .
For that reason, this study aims to investigate the surfactant and solubilization properties of saponin extracts from Jatropha curcas leaves, an area that has not so far been previously Using MAE with water as the solvent, the research examined the surfactant characteristics of the extract and their micellar solubilization properties to trapped dyes.
Additionally, to further understand the potential application of saponins as natural surfactants and solubilizing agents, the study evaluated their effectiveness in solubilizing reactive dyes in aqueous systems by determining the solubilization capacity of saponin Materials and Methods Materials Mature Jatropha curcas leaves were procured from the local plantation at Welahan.
Jepara.
Indonesia.
Pure saponin .
%) procured from Sigma Aldrich as the saponin comparative Reactive dye remazol red RB and remazol blue TQ were used to prepare the wastewater model.
Meanwhile, the dye was obtained from a local dye manufacturer (Natt Collection.
Surakarta.
Indonesi.
Pre-treatment of raw material Before extraction, the size of dry Jatropha sp.
leaves was reduced using grinder and sieved to obtain a fine powder (<100 Then, powder was stored in a jar equipped with silica gel to keep it dry for further applications.
Extraction of saponin The dried powder of Jatropha sp.
leaves was extracted using MAE with the help of a multimode microwave oven (Elektrolux.
Indonesi.
at the frequency of 2.
45 GHz and the maximum output power of 800W.
The operating procedure of MAE was adopted from the previous studies .
The powder of Jatropha sp.
leaves was solubilized in water solvent at the ratio of 20-60 mL/g.
The mixtures were mixed and irradiated at various powers .
, 720, and 800W), temperatures .
15, 353.
15, 363.
15, and 373.
15K), and times .
,3,6, and 9 minute.
where simple one factor at a time approach was used and total extracted saponin content was taken as the main parameter.
The temperature of the MAE apparatus was kept by Cowing coolant liquid using pump in and out of the condenser.
The extract obtained was then filtered under vacuum condition and evaporated using rotary evaporator (IKA RV 10 Basi.
Total saponin compound analysis The total saponin compound (TSC) was determined by spectrophotometry method .
based on the absorbance of the aqueous Jatropha sp.
leaf extract at 276.
5 nm using a UV-VIS Commercial pure saponin solution at various concentrations was used as a standard to generate a calibration curve.
A linearized equation was used to calculate the final saponin concentration .
The TSC .
was calculated based on the total saponin amount (TSa.
and the initial leaf powder, using Eq.
Surfactant properties of the saponin extract from Jatropha curcas leaves Saponin extracted from Jatropha sp.
leaves was analyzed for its surfactant characteristics based upon the following analyses in comparison to pure saponin.
FT-IR analysis A qualitative analysis of the extract was conducted by means of an FT-IR analyzer (Merk L160000A.
USA, or Shimadz.
to identify the specific functional groups of saponins.
The solutions of saponin extract were used as-is.
HPLC analysis The presence of saponin in Jatropha sp.
leaves extracts was measured using HPLC (LC20AD.
Shimadzu.
Japa.
analysis, at the wavelength of 207nm.
Here, the calibration curve of pure saponin was used as the standard .
Critical micelle concentration measurement of saponin from Jatropha curcas leaves The critical micelle concentration (CMC) was determined based on the surface tension of the diluted saponin extracts .
1-2 wt.
%) using the capillary rise method .
CMC was identified as the lowest concentration where surface tension plateaued, indicating micelle formation.
Pure saponin CMC served as control.
In this method, when a liquid rises in a capillary tube, the surface tension () can be calculated based on the capillary tube radius .
, liquid density (A), and capillary rise height .
when OO 0A .
os = .
using Eq.
Micellar solubilization of dyes Dye solubilization was assessed based on the method by Samal et al.
using remazol red RB and remazol blue TQ as the model of reactive dyes.
Saponin extract at optimal yield and pure saponin were used as surfactants.
Solutions were prepared at 1000Ae16,000 ppm, covering concentrations below, at, and Aryanti et al.
/ Communications in Science and Technology 10.
52Ae58 above the CMC.
Each was mixed with 10,000 ppm dye and shaken at 200 rpm for 24 h at 28 A 2AC.
After incubation, samples were centrifuged (DM0412.
DLAB Scientific Inc.
and the supernatants were analyzed for dye and saponin concentrations via UV-Vis spectrophotometry.
Absorbance was measured at each max of the dyes and quantified using calibration curves.
The measured dye concentrations, considered as the solubilized dye, were used to calculate solubilization capacity using Eq.
where Sdye and SCMC are the dye concentration at saponin concentration and CMC.
Micellar solubilization measurements The value of molar solubilization power (SP) can explain the dye solubilization properties of the saponin micelles, representing the amount of solubilized dye per moles of micellized saponin.
SP was calculated from the slope of the linear plot between solubilized dye concentration and saponin It may also be expressed in mass units .
, after conversion using the molecular weights of both dye and To assess solubilization effectiveness, the partition coefficient (K.
was also determined, expressing the ratio of dye distribution between micellar and aqueous phases .
, calculated using Eq.
where Vw is the molar volume of water .
,805x10-2 L.
mol-1 at 15K) and SCMC is dye concentration at CMC.
The feasibility of the dye solubilization on surfactant micelles was presented by Gibbs free energy (OIG), calculated with following .
Fig.
FTIR transmittance spectra of pure saponin.
Jatropha sp.
powder and extract HPLC analysis Further confirmation of saponin presence was obtained through HPLC analysis.
Saponin extract was analyzed and compared with the database of pure saponin chromatogram.
Figure 2 shows the HPLC chromatogram of Jatropha sp.
HPLC analysis confirmed the presence of saponins in Jatropha sp.
leaf extract, as indicated by two main peaks at retention times of approximately 1.
331 and 2.
000 minutes, which closely matched the retention times of the saponin standard .
179 and 1.
990 minute.
These findings are consistent with the previous study, which evaluated saponinbased natural surfactants for enhanced oil recovery .
The study reported a saponin standard retention time of 2.
1 minutes, with shorter retention times potentially attributed to differences in extraction techniques.
Additionally, the third peak and its shift suggested the presence of other compounds, indicating that it no longer corresponded to saponins in Jatropha sp.
The HPLC results as presented in Figure 2 further confirmed the presence of saponins in the extract.
Results and Discussion FTIR analysis of saponin The FTIR spectra of Jatropha sp.
leaf powder, leaf extract, and pure saponin were analyzed and compared with data from literature .
,18,.
Fig.
1 presents the IR spectra for the The FTIR spectrum of the saponin standard showed absorption bands at 3393.
9 cmAA for hydroxyl (O-H) stretching, 16 cmAA for carbon-hydrogen (C-H) stretching, 1609.
cmAA for carbon-carbon double bond (C=C) stretching, and 05 cmAA for carbon-oxygen (C-O-C) stretching.
Similarly, all samples exhibited spectra comparable to the saponin standard with O-H stretching ranging from 3307.
13 cmAA to 3292 cmAA.
C-H stretching at 2919.
56 cmAA.
C=C stretching 69 cmAA to 1624.
84 cmAA, and C-O-C stretching 82 cmAA and 1016.
62 cmAA.
The strong similarity between the FTIR spectra of the saponin standard and Jatropha leaf powder and extract confirmed the presence of saponins in the samples.
Fig.
HPLC chromatograms of Jatropha sp.
leaves extract 4wt% Microwave-assisted extraction of saponin from Jatropha The extraction process was carried out via the MAE method with water as the solvent chosen due to its cost effectiveness, high dielectric constant, and environmentally Aryanti et al.
/ Communications in Science and Technology 10.
52Ae58 friendly nature .
,22,.
The results of the extraction process for various extraction conditions are shown in Fig.
3, 4 and 5.
increased with temperature.
nevertheless, at the extraction temperature of 373.
15 K.
TSC decreased to 20.
02 mg/g, indicating thermal degradation.
These findings demonstrated a general trend in extraction efficiency where yield improves up to an optimal temperature before declining due to compound Fig.
Effect of the solvent-to-feed ratio on the TSC of Jatropha sp.
extracts at 363.
15 K for 3 min Fig.
3 shows the effect of solvent-to-feed ratio on the result of the extraction.
The solvent-to-feed (S:F) ratio is a crucial parameter in MAE .
Proper S:F ratio ensures adequate wetting of the plant matrix and efficient microwave absorption .
The TSC increased from 20.
06 mg/g to 35.
04 mg/g as the S:F ratio increased from 20:1 to 30:1 .
L/.
, showing that the increase of S:F ratio improved both wettability and microwave absorption within the material matrix.
However, further increase on the ratio resulted in excessive water content, which absorbed more microwave energy due to its dielectric properties, ultimately reducing the total yield of saponin compounds as shown by the decrease of the TSC to 11.
84 mg/g at higher S:F ratios of 60:1.
Additionally, an increased solvent volume generate more heat within the microwave system, potentially causing the evaporation of thermolabile compounds .
Thermolabile compounds degrade when continuously exposed to high temperatures at their boiling point .
The previous study confirmed that combining an optimized solvent system with MAE is an effective strategy for bioactive compound recovery .
Similarly, another study demonstrated that saponin content is significantly determined by extraction time, solvent concentration, irradiation time, and solvent-to-sample ratio .
Irradiation time is another critical factor in MAE.
While increasing irradiation time generally enhances yield, exceeding an optimal threshold can lead to reduced extraction efficiency.
Figure 4 presents the TSC of Jatropha sp.
leaf extracts at various irradiation times.
The highest TSC of 35.
04 mg/g was obtained at 3 minutes of irradiation.
However, yields declined at 6 and 9 minutes, likely due to the degradation of bioactive These findings align with previous studies indicating that while MAE yield initially increased with irradiation time, prolonged exposure at high temperatures .
15 K) could cause the significant degradation of saponins and other biologically active compounds .
Extraction temperature plays a vital role in determining Higher temperatures commonly accelerate extraction, reducing the required processing time.
However, in some cases, excessive temperatures can degrade sensitive components.
The effect of temperature on TSC is shown in Fig.
Initially.
TSC Fig.
Effect of irradiation time on the TSC of the Jatropha sp.
extracts at a temperature of 363.
15 K and the solvent-to-feed ratio of 30 mL/g Moreover, the saponin solubility increases along with the increasing temperature, as higher temperatures enhance solvent penetration, allowing saponins to dissolve more readily and migrate from the plant matrix into the bulk phase.
Additionally, elevated temperatures increase the porosity of the solid matrix and reduce solute viscosity, making it easier for saponin molecules to interact with the solvent, and be extracted .
However, the excessive rise of the temperatures decreases the calculated TSC, indicating the decomposition of saponin compounds .
Fig.
Effect of extraction temperature on total saponin compound yield The TSC was analyzed spectrophotometrically, which relied on the chromophoric groups of the saponin e.
triterpenoid/steroid core or conjugated double bonds .
Intact saponins strongly absorb light at their characteristic However, if degradation disrupts the conjugation of the molecule, this will promote cleavage on the glycosidic bonds, and produce smaller molecules that absorbs less light, thus reducing the detected concentration .
Consequently, this reduction reflects compound alteration.
Similar result was also reported in phenolic extraction, where temperature initially Aryanti et al.
/ Communications in Science and Technology 10.
52Ae58 gave a positive shift on the extraction result and showed a decrease after the optimum temperature condition achieved .
The molecular structure of saponin is depicted in Fig.
could be expressed in millimolar .
M) with 4.
86 mM for extract saponin and 2.
45 mM for pure saponin.
The micelle formation mechanism is illustrated in Fig.
Fig.
The illustration of the micelle form mechanism Fig.
Molecular structure of saponin Analysis of CMC of saponin and micelle property In a liquid solution, surfactant monomers aggregated into micelles at a specific concentration are known as the critical micelle concentration (CMC).
These micelles play a crucial role in adsorbing organic solutes, such as dyes .
In this study, the CMC value was determined by analyzing the decline in the water surface tension by varying the saponin concentrations, as presented in Figure 7.
Solubilization of dyes A dye solubilization experiment was conducted using saponin extracted from Jatropha sp.
leaves as a natural surfactant to assess its micelle-forming capabilities.
The effect of saponin concentration on the solubility of Remazol Red RB and Remazol Blue TQ is illustrated in Fig.
Fig.
Effect of saponin concentration .
n mM) on the solubility of remazol red RB and remazol blue TQ at 28 A 2oC Fig.
Measurement of CMC of surfactants by capillary rise method Generally, water surface tension decreases with the addition of saponin into solutions.
However, beyond a certain concentration, surface tension remains nearly constant despite the continued addition of saponin, indicating the critical micelle concentration (CMC).
Pure saponin showed CMC of 0.
3 wt.
aligning with the reported CMC range provided by the manufacturer at 0.
001Ae0.
1 wt.
Saponin extracted from Jatropha sp.
Leaves obtained higher CMC of 0.
6 wt.
This value was calculated based on the total saponin yield obtained under optimal extraction conditions.
The higher CMC of the extract compared to pure saponin may be attributed to the presence of impurities in the extracted solution.
Similar findings have been reported in previous studies where extract solutions exhibited higher CMC values than that of pure saponin .
Assuming that the molecular weight of the extracted and pure saponin was identical, the CMC values The reactive dyes solubilization capacity of the saponin micelles was analyzed at concentrations below and above the CMC.
The previous report found that a solubilization period of 18Ae24 hours was sufficient to achieve equilibrium as no significant increase in dye solubilization was observed beyond 24 hours .
Whereas, this study confirmed that equilibrium reached within 24 hours.
Fig.
depicts the solubilized dye .
n mM) as the function of TSC.
The results demonstrated the increase of dye solubility by the addition of surfactant concentration, even beyond the CMC, indicating the significant role of surfactant micelles in dye solubilization.
Micelle agglomerates may also adsorb dye molecules and this furthermore can increase solubilization .
These findings align with a previous study, reporting that the micelles solubilized dyes by facilitating the solute movement into their structures .
This process involved the interactions of surfactant, water and dyes.
Surfactant forms amphiphilic micelles, which bind solutes at concentrations above the CMC.
Micelles facilitate the dissolution of highly water-soluble Aryanti et al.
/ Communications in Science and Technology 10.
52Ae58 According to Huang et al.
surfactant micelles consist of three distinct layers: hydrophobic inner core.
CH2based palisade layer and hydrophilic outer layer.
However, the exact location of solubilization within non-ionic surfactant micelles remains unclear.
Some researchers have proposed that solubilization occur in both hydrophilic-hydrophobic regions .
While, the relative solubilization in these regions depends on the polarity of the dyes .
The polar outer portion leading to the preferential retention of polar solutes.
Consequently, polar molecules, such as dyes, may be partially incorporated into the outer region of the surfactant micelles .
leaf extract as a sustainable surfactant and solubilizing agent for reactive dyes.
Microwave-assisted extraction significantly enhanced the yield of saponins with the highest yield of 35.
mg/g.
FTIR analysis confirmed that the functional groups of the extracted saponin were comparable to those of pure saponin.
The CMC of the extracted saponin .
3 wt.
%) was lower than that of pure saponin .
6 wt.
%), indicating superior surfactant Meanwhile, thermodynamic analysis revealed negative iG for dye solubilization, confirming feasible and spontaneous dye solubilization.
The results of the study highlights the potential of Jatropha curcas leaf extract as an eco-friendly alternative to synthetic surfactants, particularly in applications such as reactive dye solubilization.
Acknowledgements Financial support is provided by the Faculty of Engineering.
Universitas Diponegoro with a Strategic Research scheme for 2023 .
/UN7.
F3/HK/IV/2.
Fig.
The mechanism of dye solubilization of saponin for remazol red RB and remazol blue TQ Furthermore, the molar solubilization power (SP) of saponin was 5.
40- and 5.
08-mM dye/mM saponin for Remazol Red RB and Blue TQ, respectively.
The higher solubilization capacity of saponin micelles for Remazol Red RB compared to Remazol Blue TQ attributed to the molecular weights differences between the dyes.
The structural difference between the dyes also influenced their solubilization behavior.
Since the molecular structure of Remazol Red RB was smaller than that of Remazol Blue TQ, it was expected to exhibit higher solubilization efficiency.
References