Simultaneous synthesis of super-paramagnetic hydrochar in a one-pot using subcritical water medium and evaluation of its photocatalytic activity.

The unregulated release of chemical dyes into the environment presents considerable environmental hazards when left untreated. Photocatalytic degradation, acknowledged as an eco-friendly and cost-effective method, has garnered attention for its efficacy in eliminating organic pollutants like dye. Consequently, the development of multifunctional materials with different applications in environmental and catalytic fields emerges as a promising avenue. Recognizing the significance of integrating catalysts and porous materials for enhancing interactions between pollutants and photo-sensitive substances, magnetic hydrochar emerges as a solution offering heightened efficiency, scalability, recyclability, and broad applicability in various environmental processes, notably wastewater treatment, due to its facile separation capability. In this study, Fe3O4-based, super-paramagnetic hydrochar (SMHC) was simultaneously synthesized in a single step using a coconut shell in the subcritical water medium. A thorough analysis was conducted on both raw hydrochar (RHC) and SMHC to unravel the mechanism of interaction between Fe3O4 nanoparticles and the hydrochar matrix. The synthesized hydrochar exhibited super-paramagnetic characteristics, with a saturation magnetization of 23.7 emu/g and a magnetic hysteresis loop. SMHC displayed a BET surface area of 42.6 m2/g and an average pore size of 26.3 nm, indicating a mesoporous structure according to nitrogen adsorption-desorption isotherms. XRD analysis revealed magnetic crystal sizes in the obtained SMHC to be 13.7 nm. The photocatalytic performance of SMHC was evaluated under visible light exposure in the presence of H2O2 for Astrazon yellow (AY) dye degradation, with optimization conducted using response surface methodology (RSM). The most substantial dye removal, reaching 92.83%, was achieved with 0.4% H2O2 at a 20 mg/L dye concentration and an 80-min reaction duration.

Unlocking nature's potential: anticancer potential of Helichrysum sanguineum (L.) Kostel on breast cancer cells and its chemical composition.

Helichrysum sanguineum (L.) Kostel (H. sanguineum), a member of the Asteraceae family, has been traditionally employed for various medicinal purposes owing to its rich phytochemical composition. This study investigates the anticancer properties of various extracts of H. sanguineum (ethanol, acetonitrile, hexane, and chloroform) against breast cancer cells, shedding light on its chemical constituents and their potential therapeutic effects. In vitro assays demonstrate the profound inhibitory effects of H. sanguineum extract on human fibroblast and breast cancer cells. Furthermore, we elucidate the underlying mechanisms of action, revealing its ability to induce apoptosis and cell cycle arrest in breast cancer cells. The cytotoxicity and apoptosis outcomes in breast cancer cells varied across different extracts, yet no adverse effects were observed on healthy cells at equivalent concentrations. Furthermore, all extracts initially promoted breast cancer cell proliferation, with the chloroform extract notably reducing cancer cell proliferation even at low concentrations. GC-MS analysis identifies the major chemical constituents of the extract, including flavonoids, terpenoids, and phenolic compounds, which likely contribute to its anticancer activity. Our findings highlight the potential of H. sanguineum extract as a natural agent for breast cancer treatment and the need for further exploration of its mechanisms and clinical applications.

Inhibition performance of almond shell hydrochar-based fish oil emulsion gel on Klebsiella pneumonia inoculated fish skin and its characteristics.

In this study, the inhibition potential against Klebsiella pneumoniae (K. pneumoniae) and the characterization of fish oil (FO) emulsion gel (EGE) containing almond shell hydrochar (AH) were investigated. Oily water of mullet liver was emulsified using tween 80, then gelled using gelatin and finally immobilized into hydrochar using an ultrasonic homogenizer. Characteristics and surface analysis of hydrochar-based emulsion gel (HEGE) were examined using FTIR and SEM. Stability, particle size distribution and zeta potential of HEGE were measured. In this study, a zeta potential of -18.46 indicated that HEGE was more stable than EGE (35.7 mV). The addition of hydrochar to the emulsion gel containing micro-droplets enabled the structure to become fully layered and stable. Time-dependent inactivation of K. pneumoniae exposed to HEGE and fixed in 6 mm-fish skin was evaluated for the first time in this study. While the highest log reduction and percent reduction in the bacterial count were achieved within 5 min with 0.87 CFU/cm2 and 86.60% with EGE, the lowest log reduction and percent reduction were achieved with 0.003 CFU/cm2 and 0.082% with HEGE in 30 min. In conclusion, the almond shell hydrochar-immobilized emulsion gel is a functional adsorbent that can inhibit K. pneumonia, and its stability and performance make it a unique candidate for further studies in this field.

A natural approach to breast cancer treatment: investigation of chemical features of aerial parts of endemic Onosma sintenisii Hausskn. ex Bornm and its antioxidant properties, in vitro cytotoxic and apoptosis induction on MCF-7 cells.

Onosma sintenisii Hausskn. ex Bornm. (O. sintenisii) belongs to the Boraginaceae family and it is an endemic species from Irano-turanian phytogeographical region (central and eastern Anatolia) that distributes in steppe areas. This study aimed to investigate the chemical composition, antioxidant, in vitro cytotoxic and apoptosis induction of methanol extract of aerial parts of O. sintenisii. As a result of GC/MS analysis, 14 components were identified, and the major compounds of the extracts are retronecine (13.94%), α.-D-Glucopyranosiduronic acid (10.86%), melaniline (7.5%) and 1,2-Butanediol (4.02%), respectively. Antioxidant properties of O. sintenisii were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and superoxide radical scavenging activity methods. While the DPPH free radical scavenging activity results of O. sintenisii extract varied between 62.49% and 32.27%, reducing power activity and superoxide radical scavenging activity were found to be low. The result of the MTT assay revealed strong anticancer activity of O. sintenisii extract. The most significant cytotoxic effect was noted at a concentration of 1000 µg/mL after 48 hours. These findings together with flow cytometry analysis suggest that apoptosis can be the main mechanism underlying cell death after O. sintenisii extract treatment.

A Review: Subcritical Water Extraction of Organic Pollutants from Environmental Matrices.

Most organic pollutants are serious environmental concerns globally due to their resistance to biological, chemical, and photolytic degradation. The vast array of uses of organic compounds in daily life causes a massive annual release of these substances into the air, water, and soil. Typical examples of these substances include pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Since they are persistent and hazardous in the environment, as well as bio-accumulative, sensitive and efficient extraction and detection techniques are required to estimate the level of pollution and assess the ecological consequences. A wide variety of extraction methods, including pressurized liquid extraction, microwave-assisted extraction, supercritical fluid extraction, and subcritical water extraction, have been recently used for the extraction of organic pollutants from the environment. However, subcritical water has proven to be the most effective approach for the extraction of a wide range of organic pollutants from the environment. In this review article, we provide a brief overview of the subcritical water extraction technique and its application to the extraction of PAHs, PCBs, pesticides, pharmaceuticals, and others form environmental matrices. Furthermore, we briefly discuss the influence of key extraction parameters, such as extraction time, pressure, and temperature, on extraction efficiency and recovery.

A broad assessment of Eremurus spectabilis M. Bieb: chemical and elemental composition, total phenolic and antimicrobial activity analysis, and quantum chemical calculations of radical scavenging potential.

Eremurus spectabilis M. Bieb was extensively investigated experimentally and theoretically, including the antioxidant properties of compounds such as flavonoids, hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, and organic acids. Antioxidant activity was investigated using the Density Functional Theory (DFT) method based on three known mechanisms: hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Subcritical water extraction (SWE), soxhlet extraction (SE), and solvent extraction (SOE) techniques were applied in the extraction process. Malic acid was the major compound with an extract concentration of 38,532.84 ± 1849.58 µg analyte/kg, total phenolics, and free radical scavenging activity were 10.67 mg gallic acid/mL extract and 73.89% per mg/mL extract, respectively. P, Fe, Na, Mg, K, and Ca were the main elements. The antibacterial activity of E. spectabilis against seven bacteria was evaluated, and it was found to be higher than the commercial antibiotics P10 and AMC30.

Recent advances in environmental and agricultural applications of hydrochars: A review.

Hydrochar is a carbonaceous material that is generated through the process of hydrothermal carbonization (HTC) from biomass, which has garnered considerable attention in recent years owing to its potential applications in a diverse range of fields, such as environmental remediation and agriculture. Hydrochar is produced from a diverse range of biomass waste materials and retains exceptional properties, including high carbon content, stability, and surface area, making it an optimal candidate for various enviro-agricultural applications. Moreover, it delves into the production process of hydrochar, with explicit emphasis on the optimization of certain properties during the production of hydrochar from bio-waste. Furthermore, the potential of hydrochar as an adsorbent and catalyst support for heavy metals and dyes was extensively explored, along with a soil remediation potential that can improve the physical, chemical and biological properties of soil. This comprehensive review aims to provide a thorough overview of hydrochar with a particular focus on its production, properties, and prospective applications. The significance of hydrochar is accentuated and the growing need for alternative sources of energy and materials that are environmentally sustainable is highlighted in this paper. Besides, the consequence of hydrochar on soil properties such as water-holding capacity, nutrient retention, and total soil porosity, as well as its influence on soil chemical properties such as cation exchange capacity, electrical conductivity, and surface functionality is scrutinized.

Determination of pesticide residues in varieties of pepper sold at different periods and provinces in Turkey and investigation of their adverse effects on human health and the environment.

Pesticides are dangerous chemicals that can harm to people and the environment when applied inappropriately or in excess. In this research, various pesticide residues were investigated in 48 pepper samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). All samples were collected randomly in two periods of time (September and December) from markets and greengrocers in four provinces (Siirt, Mardin, Diyarbakir, and Batman). Considering the means of the first and second periods, diclofop-methyl had the highest concentration of 29.4 ± 7.7 µg kg-1, and diazinon had the lowest of 21.1 ± 4.6 µg kg-1. Based on the maximum residue limits (MRLs) of pesticides specified in the Turkish Food Codex, pyrimethanil, bupirimate, and diclofop-methyl were found to be below the maximum acceptable residue limit, while pyridaphention, dinoseb, diazinon, and pirimiphos-methyl were found to be above the limit. Thus, the current study demonstrated the potential of LC-MS/MS as a crucial technique for accurate measurements and confirmations of pesticides in different pepper varieties.

Physico-chemical adsorption of cationic dyes using adsorbent synthesis via hydrochloric acid treatment and subcritical method from palm leaf biomass waste.

Today, where water resources are polluted rapidly, the need for eco-friendly green methods is gradually increasing. Conversion of waste biomass into functional adsorbents that can be utilized in water treatment is a win-win practice for both recycling and water pollution treatment. In this study, the adsorbent material was obtained from the palm leaf to contribute to sustainable green energy. This cellulose-containing adsorbent material was tested in the removal of Methylene Blue (MB) and Basic Red-18 (BR18). The properties of palm leaf adsorbent were determined. The best removal efficiencies and optimum conditions were determined in the adsorption process. In both dye types; the original pH value, 2 g/L adsorbent dose, 25 mg/L dye concentration, and 120 min were chosen as the optimum conditions since the best removal efficiency was obtained in the experiments performed at 25 °C. At these conditions, the removal efficiencies were found to be 100% and 90% for BR18 and MB, respectively. In addition, adsorption kinetics, isotherms, and thermodynamic data were analyzed. For BR18 and MB, it was found to fit the Langmuir isotherm and pseudo-2nd order. Palm leaf adsorbent was used with an efficiency of over 50% in four consecutive cycles.

Heterologous expression, purification, and characterization of thermo- and alkali-tolerant laccase-like multicopper oxidase from Bacillus mojavensis TH309 and determination of its antibiotic removal potential.

Laccases or laccase-like multicopper oxidases have great potential in bioremediation to oxidase phenolic or non-phenolic substrates. However, their inability to maintain stability in harsh environmental conditions and against non-substrate compounds is one of the main reasons for their limited use. The gene (mco) encoding multicopper oxidase from Bacillus mojavensis TH309 were cloned into pET14b( +), expressed in Escherichia coli, and purified as histidine tagged enzyme (BmLMCO). The molecular weight of the enzyme was about 60 kDa. The enzyme exhibited laccase-like activity toward 2,6-dimethoxyphenol (2,6-DMP), syringaldazine (SGZ), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The highest enzyme activity was recorded at 80 °C and pH 8. BmLMCO showed a half-life of ~ 305, 99, 50, 46, 36, and 20 min at 40, 50, 60, 70, 80, and 90 °C, respectively. It retained more than 60% of its activity after pre-incubation in the range of pH 5-12 for 60 min. The enzyme activity significantly increased in the presence of 1 mM of Cu2+. Moreover, BmLMCO tolerated various chemicals and showed excellent compatibility with organic solvents. The Michaelis constant (Km) and the maximum velocity (Vmax) values of BmLMCO were 0.98 mM and 93.45 µmol/min, respectively, with 2,6-DMP as the substrate. BmLMCO reduced the antibacterial activity of cefprozil, gentamycin, and erythromycin by 72.3 ± 1.5%, 79.6 ± 6.4%, and 19.7 ± 4.1%, respectively. This is the first revealing shows the recombinant production of laccase-like multicopper oxidase from any B. mojavensis strains, its biochemical properties, and potential for use in bioremediation.

Hydrochar synthesis from waste corncob using subcritical water and microwave-assisted carbonization methods and ammonium enrichment of synthesized hydrochars.

Corncob (CC) is an industrial biological waste that is generated in significant quantities, and converting such biological wastes into value-added hydrochars through a viable process such as hydrothermal carbonization can provide significant benefits. It is of great importance to ensure eco-friendly and appropriate methods that are suitable for the area where the hydrochar will be used. This study aimed to synthesize hydrochars from a solid food waste, CC, using two different hydrothermal carbonization methods based on microwave-assisted (MHC) and subcritical water (SHC) using them as a biosorbent for NH4+ adsorption from water and characterizing their specific features. Hydrochars were synthesized in 1 h at 180 °C and 240 °C by MHC and SHC methods, respectively. Hydrochars synthesized by MHC and SHC methods were characterized by SEM-EDX, N2 adsorption-desorption isotherms, and FT-IR analyses. According to the EDX results, the C/O ratio (atomic %) in MHC and SHC was determined to be 0.55 and 0.35, respectively. Nitrogen adsorption-desorption isotherms revealed that hydrochars obtained by both methods have three distinct pore types, namely, micro, meso, and macro. In the energy consumption per unit adsorbent, a lower value was obtained for MHC than SHC. NH4+ adsorption using MHC and SHC was found to be compatible with the Langmuir isotherm model and the NH4+ adsorption capacities were 13.09 and 10.54 mg/g, respectively. pH was the most effective variable on hydrochars in the NH4+ adsorption based on the response surface method (RSM), and the highest adsorption occurred at pH 6.5 and 40 mg/L of initial NH4+ concentration, using 1.5 g/L of adsorbent at 35 °C. The results revealed that MHC is a unique method that can be used for hydrochars derived from CC in NH4+ adsorption, and MHC is more cost-effective than SHC in hydrochar production.

Solubility and Decomposition of Organic Compounds in Subcritical Water.

In this article, studies on organic solubility and stability in subcritical water reported during the past 25 years have been reviewed. Data on the solubility and decomposition of organic compounds in subcritical water, a green solvent, are needed in environmental remediation, chemistry, chemical engineering, medicine, polymer, food, agriculture, and many other fields. For solubility studies, the experimental systems used to measure solubility, mathematical equations derived and applied for the modeling of the experimentally determined solubility data, and the correlation between the predicated and experimental data have been summarized and discussed. This paper also reviewed organic decomposition under subcritical water conditions. In general, the solubility of organics is significantly enhanced with increasing water temperature. Likewise, the percentage of organic decomposition also increases with higher temperature.

Natural sanitizer potential of Cuminum cyminum and applicable approach for calculation of Kováts retention index of its compounds.

The demand for natural agents instead of chemicals in terms of food and health safety is increasing day by day. This study aimed to investigate the potential of the methanolic extract of Cuminum cyminum (C. cyminum) in the fight against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus)and Candida (C. albicans). The chemical composition of the methanolic extract of C. cyminum was analyzed using GS-MS. Also, Kováts retention indices were calculated for the detected compounds using an applicable formula. The most basic substance was cuminic aldehyde (27.86%) and p-(Dimethoxymethyl)-isopropylbenze (18.32%). The Minimum Inhibitory Concentration (MIC) of the extract was 0.1 g/mL for S. aureus and C. albicans while it was > 0.1 for E. coli. Although the methanol extract of C. cyminum acts against all three microorganisms, the most lasting effect was on S. aureus, indicating that it can be recommended as a strong antibacterial disinfectant for S. aureus.

Can Origanum be a hope for cancer treatment? A review on the potential of Origanum species in preventing and treating cancers.

In this study, the potential of aromatic Origanum species belonging to Lamiaceae family to prevent and treat cancer was investigated. Since aromatic plants contain phytochemicals such as essential oils, phenolic acids, terpenoids, flavonoids, alkaloids, vitamins, enzymes and minerals with beneficial biological activities, they have become more interesting and important in medicine, pharmacy and industry. Publications/research between 1950 and 2022 were screened to investigate the effects of Origanum species on cancer, and the effects of their extracts and essential oils in cancer prevention and treatment. Essential phytochemicals found in plants provide efficacy in the prevention and treatment of many diseases. Besides, the essential oils found in these plant extracts are another reason that makes them important. Therefore, it is preferred in traditional medicine in the fight against many diseases as well as cancer. Essential oils of Origanum species mainly contain monoterpenes such as p-cymene, carvacrol, thymol and γ-terpinene. Since these compounds exhibit anticancer properties, Origanum species are becoming the plants of choice in the fight against cancer. In this context, Origanum majorana L. Origanum vulgare and Origanum munzurense are promising species, considering the composition of their extracts and essential oil.

Anticancer potential of Origanum munzurense extract against MCF-7 breast cancer cell.

Origanum munzurense (O. munzurense) is an endemic species of Tunceli region of Turkey. In this study, we investigated in vitro anticancer effect of aqueous extract of O. munzurense (OME) on breast cancer cells (MCF-7). In vitro cytotoxic effect of OME was evaluated in MCF-7 cells by MTT assay. The wound-healing assay was used to examine the inhibition of migration. Annexin V/propidium iodide staining, cell-cycle distribution was assessed by flow cytometry for MCF-7 cells treated with OME. MTT results show that OME demonstrated in vitro cytotoxicity with 600 mg at 48 h on MCF-7. Doses of 400 µg/mL and 600 µg/mL OME significantly suppressed the migration rate of MCF-7 cells. OME significantly decreased the percentage of live cancer cells and showed an apoptotic effect after 48 h of incubation. These results show that OME is effective against breast cancer when administered at high doses and for a long time.

A comparison of the performance of conventional and eco-friendly extraction methods in the evaluation of total phenolics, antioxidant activity, and chemical composition of anise.

In this work, the essential oil of Pimpinella anisum seeds was obtained by six different extraction methods. In the chemical composition analysis, 4, 6, 4, 1, 20, and 8 compounds were detected in the extracts obtained by Soxhlet, Ultrasonic-assisted (UAE), hydrodistillation using Clevenger apparatus (HDC), subcritical water extraction (SWE), supercritical carbon dioxide extraction (ScCO2) using three solvents (methanol (ScCO2-Met), ethanol (ScCO2-Et), and hexane (ScCO2-H)) and supercritical 1,1,1,2-tetrafluoroethane (ScR134a) methods, respectively. Also, the performances of the applied methods were compared by analysing the total phenolic content (TPC) and antioxidant activity of the extracts. Anethole was the main component of all extracts obtained by SWE (94.5%) and Soxhlet (94.5%) methods, respectively. Also, TPC values were the highest (508.5 mg GAE/100 g kb) in ScR134a extract and the lowest (27.77 mg GAE/100 g kb) in HDC extracts. The antioxidant capacity was found to be the highest in ScCO2-H (IC50 = 1.58 mg/mL) and the lowest in Soxhlet extracts (IC50 = 0.07 mg/mL). The results showed the great effectiveness of eco-friendly extraction SWE, ScCO2-Et, and ScR134a methods.

Preparation of hydrochar bio-based catalyst for fenton process in dye-containing wastewater treatment.

The use of synthetic dyes in the textile industry pollutes a huge amount of water. Thus, wastewater discharged from many textile companies to the receiving environment without being treated causes serious environmental and human health problems. The development of new techniques has become imperative. In this study, it was aimed to remove anionic dye (RR180) and cationic dye (BR18) by Fenton-like and adsorption process with hydrochars obtained from laurel leaves and watermelon peels. In the comparison of the adsorption and Fenton-like processes used in the dye removal of the produced bio-based materials, the Fenton-like process was selected in order to enhance the highest removal efficiency. The effects of various operating factors such as solution pH, amount of catalysts, hydrogen peroxide (H2O2) concentration, and initial dye concentration were evaluated on both dyes removal. The experimental results demonstrated that 99.8% RR180 dye and 98.8% BR18 dye removal efficiency were observed for an initial dye concentration of 100 mg/L with an adsorbent concentration of 1 g/L, H2O2 concentration of 15 µL/L, and optimum pH at the end of 60 min of reaction time. It was observed that an increase in initial dye concentration caused to decrease the dye removal efficiency. The optimum pH for the highest RR180 and BR18 dye removal was 4 and 6, respectively. It was observed that the increase in H2O2 concentration in the solution also decreased the dye removal efficiency. It turned out that catalysts obtained from hydrochars are an effective process for the high removal performance of cationic and anionic dyes.

Design and synthesis of silver nanoparticle anchored poly(ionic liquid)s mesoporous for controlled anticancer drug delivery with antimicrobial effect.

Owing to the importance of drug delivery, the synthesis of advanced nanomaterials for targeted drug delivery plays a considerable role in medical treatment. One of the most prominent nanomaterials is PIL, which is used as controlled anticancer drug delivery and significantly improves the half-life and antitumor effect. In this study, a stable and effective drug carrier containing silver nanoparticles was reported for the drug delivery with an antimicrobial effect, and the capability of the drug carrier . PILP was synthesized by radical polymerization, and silver nanoparticles were anchored into PIL voids by in-situ reduction, which developed the adsorption antimicrobial effect and capability of the drug carrier. The synthesized nanocomposite was characterized. The Ag-PILP nanocomposite showed antibacterial activityagainst both E. coli and S. aureus with a MIC of 256 µg/mL, and bactericidal activity against E. coli and S. aureus strains with a MBC of 256 and 512 µg/mL, respectively.

Catalytical efficiency, mechanism and characterization of hydrolysed waste eggshell in the subcritical water oxidation of pistachio processing wastewater.

Sustainable, effective and environmentally friendly methods are needed in wastewater treatment as quality water is necessary for a healthy life. Valorisation of solid food waste is also of great importance. This study examines the effectiveness of hydrolysed waste eggshells (HES), a green catalyst, in pistachio processing wastewater (PPWW) treatment using subcritical water oxidation (SWO). HES was prepared in the subcritical water medium (513 K, 100 bar of N2, 2 h) with a 92.3% yield. 88.8% of COD, 100% of both TPC and color removals of PPWW were achieved. The effects of independent variables such as temperature (363-403 K), treatment time (20-100 min), the concentration of H2O2 (0.25-1.25 M) and amount of catalyst (0-100 mg/100 mL) on the responses were investigated using response surface methodology (RSM). SEM, EDX and XRD were used to investigate the characterization of the waste eggshells. The percentage of Ca in HES increased with the hydrolysis, thus CaO increased the catalysis of hydrogen peroxide to form hydroxyl radicals.

Catalytic efficiency of raw and hydrolyzed eggshell in the oxidation of crystal violet and dye bathing wastewater by thermally activated peroxide oxidation method.

In this study, hydrochar-based-eggshell was prepared via the subcritical water medium (SCWM) and used as a catalyst in the thermally activated peroxide oxidation (TAPO) approach for crystal violet and dye bathing wastewater degradation. The catalytic activities for the raw eggshell (RES) and hydrochar-based-eggshell (HES) were compared. RES and HES were characterized using a scanning electron microscope (SEM),energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transforms infrared spectroscopy (FT-IR). The affecting parameters on the degradation process were optimized using response surface methodology (RSM). The effects of temperature (293-333 K), amount of catalyst (5-25 mg/50 mL), the concentration of H2O2 (0-8 mM), and treatment time (10-70 min) on the TAPO method were investigated using central composite design (CCD). For the crystal violet removal, two models were developed. Both models were significant and can be used to describe the design space. Also, the dye bathing wastewater degradation was described by another developed model, which had a high correlation coefficient (R2 = 0.97). In general, catalytic activity for HES was higher than RES. The degradation of crystal violet reached 98.10% when a 20 mg HES catalyst and 6 mM H2O2 at 323 K for 55 min were used. While 97% of the color of dye bathing wastewater was removed in 55 min at 323 K using 25 mg of HES and 4 mM H2O2. This study showed that the hydrolyzed eggshells could be used in the oxidation of crystal violet and dye bathing wastewater by the thermally activated peroxide oxidation method.