Methylene Blue Test Research Articles

The relationship between local structure and photo-Fenton catalytic ability of glasses and glass-ceramics prepared from Japanese slag

Local structure and the photo-Fenton reactivity of iron-containing glasses and glass-ceramics prepared from Japanese domestic waste slag were investigated. The largest rate constant (k) of (2.8 ± 0.08) × 10−2 min−1 was recorded for the methylene blue degradation test by using H2O2 with a heat-treated ‘model slag’. The 57Fe Mossbauer spectrum was composed of a paramagnetic doublet with isomer shift of 0.18 ± 0.01 mm s−1 attributed to distorted FeIIIO4 tetrahedra. These results indicate that the paramagnetic Fe3+ provided strong photo-Fenton catalytic ability, and that waste slag can thus be recycled as an effective visible-light activated photocatalyst.

Mössbauer and photocatalytic studies of CaFe2O4 nanoparticle-containing aluminosilicate prepared from domestic waste simulated slag

The relationship between local structure and visible-light activated photocatalytic effect of simulated domestic waste slag glass–ceramics (R-NaWSFe) was investigated. The largest pseudo-first-order rate constant of 9.75 × 10−3 min−1 was estimated for methylene blue decomposition test under the visible-light irradiation using R-NaWSFe with additional 30 mass% of Fe2O3 heat-treated at 900 °C for 100 min. The reason for the high photoactivity of this sample was mainly due to nanoparticles of CaFe2O4 and α-Fe2O3 confirmed by the Mossbauer spectrum measured at 77 K. It is concluded that the nanoparticles of magnetic components in silica are essential for exhibiting visible-light activated catalytic effect.

Characterization of the firing behaviour of an illite-kaolinite clay mineral and its potential use as membrane support

The commercial value of any clay depends on its physical and chemical properties, these could help in tuning the characteristics of ceramic membrane supports required at extreme filtration conditions. The characteristics of two clay minerals named SA and CH were studied at various firing temperatures. The composition in oxides of both raw materials consisted of quartz (44.40 ± 0.60 to 46.98 ± 0.57 m%), alumina (13.16 ± 0.56 to 19.64 ± 0.48 m%), iron oxide (4.85 ± 0.46 to 6.37 ± 0.70 m %), and relatively smaller amounts of alkaline-earth oxides (3.34 ± 0.43 to 5.98 ± 0.33 m% calcium oxide and 1.98 ± 0.18 to 5.87 ± 0.34 m% for magnesium oxide). XRD of the investigated samples indicated the presence of kaolinite and illite as pure clay fractions in the clay mineral. SEM showed that the clay minerals were constituted from fine poorly crystalline particles with particles’ size more than 5 μm. The specific surface areas of the clay minerals were found to vary between 94.5 ± 6.3 to 138.6 ± 4.2 m2/g using methylene blue stain test, indicating that, the clay minerals fall within chlorite, illite, and kaolinite categories. The porosity of the clay supports made from both clays were found to be maximal with values of 23.45% ± 0.66 and 21.61% ± 0.60 for SA and CH clay materials respectively at 700°C. These values were a direct result of capillary movements of water in the specimen pores that were opened to the outside leading to the highest number macropores and mesopores in the specimen.

ANTIFUNGAL EFFECT OF PHOTOCATALYTIC NANO -TITANIUM DIOXIDE INCORPORATED IN SILICONE ELASTOMER:

INTRODUCTION: Titanium dioxide nanoparticles may improve the antifungal properties of silicone elastomer prosthetic materials. OBJECTIVES: To evaluate the photocatalytic antifungal activity of silicone elastomer incorporated with titanium dioxide nanoparticles against Candida albicans. MATERIALS AND METHODS Titanium dioxide nano-particles (Aeroxide® TiO2 P25, Sigma Aldrich, USA) were characterized using xray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), uv-vis spectrophotometeric analysis, methylene blue degradation efficiency test and direct contact test. Sixty six disc shaped specimens (6 mm diameter x 1mm thickness) of silicone elastomer (SE) (MED-4210, Factor II, USA) were included and divided into 6 groups based on the concentration of nano-TiO2 in silicone elastomer (0%, 2%, 4%, 6%, 8%, 10%) (W/W). Impregnated culture test was used to evaluate the antifungal activity of all SE samples against candida albicans as colonies forming units (CFUs) of treated aqueous suspension of candida albicans were measured at 0, 30, 60, 90 and 120 min follow‑up under UVA light. The dispersion of TiO2 within SE matrix was analysed by Laser scanning microscopy (LSM). RESULTS: Data were analysed using ANOVA test and Tuckey's Post Hoc test. Nano-TiO2 characterization tests confirmed the crystalline structure (85% anatase and 15% rutile), shape (irregular faceted), size (22nm), absorption spectrum (320-400nm) and the photocatalytic antifungal ability of the as-purchased Aeroxide TiO2 P25. Planktonic cultures of candida albicans exposed to SE/TiO2 samples reduced candida albicans count by 4% - 99.99%, depending on the nanoparticles concentration and follow-up time. The candida albicans counts did not decrease in group I without TiO2. LSM of SE specimens showed finer dispersion of TiO2 within SE matrix in group II, III and IV than that in group V and VI. CONCLUSIONS: Incorporation of TiO2 P25 within SE (MED-4210) shows promising inhibitory activity against candida albicans.

One-pot synthesis of Au/N-TiO2 photocatalysts for environmental applications: Enhancement of dyes and NOx photodegradation

Au/N-TiO2 photocatalysts with enhanced photoactivity thanks to nitrogen doping and gold nanoparticles (AuNPs) controlled deposition onto titania have been obtained by means of a simple and innovative one-pot synthesis promoting synergetic activity between these two approaches. The activity of the materials under study was evaluated by methylene blue and NOx degradation tests as models of environmental remediation processes for water purification and air depollution. The use of a deposition-precipitation method employing urea allows obtaining Au/N-TiO2 photocatalysts containing 0.3 at.% of nitrogen and 0.5 wt% of gold. The results obtained confirmed that the presence of both, nitrogen and AuNPs, enhanced the TiO2 photoactivity increasing the photodegradation of the dye and NOx in a factor of 4.5 and 1.7, respectively. In particular, the AuNPs enabled the photoactivity under visible light and improved substantially the selectivity of the NO degradation process. The photocatalysts here proposed maintain their properties as they are integrated into a silica matrix producing a product with potential use for the coating of different substrates, such as building materials for application in urban areas and fabrics or foams for the photocatalytic filters production.

Recurrent Aspiration Pneumonia in a Missed Case of Broncho-Esophageal Fistula with Repaired Esophageal Atresia: Usefulness of Fiberoptic Bronchoscopy: A Case Report

: Broncho-esophageal fistula (BEF) is a rare congenital anomaly affecting the respiratory and upper gastrointestinal tract. The rarity makes its timely diagnosis very challenging. This study presents a rare case of missed congenital BEF in a six-year-old girl with repaired esophageal atresia in the neonatal period suffering from recurrent respiratory symptoms, choking, and respiratory distress following eating, resulting in vomiting or regurgitation for three years before admission. While the contrast esophagography and endoscopy had failed to diagnose her problem, the methylene blue test via an esophageal catheter observed by fiberoptic bronchoscopy could detect the presence of BEF reliably in the present case. Presenting this case can raise physicians’ knowledge of the diagnostic role of methylene blue test via fiberoptic bronchoscopy.

Staple-line leak post primary sleeve gastrectomy. A two patient case series and literature review

There is an increasing trend in the number of bariatric surgeries performed worldwide, partly because bariatric surgery is the most effective treatment for morbid obesity. Sleeve gastrectomy (SG) remains the most common bariatric surgery procedure performed, representing more than 50% of all primary bariatric interventions. Major surgical complications of SG include staple-line bleeding, leaking, and stenosis. A leak along the staple-line most commonly occurs at the gastroesophageal junction (GOJ).From January 2018 to December 2018, our centre performed 226 bariatric procedures, of which, 97.8% were primary bariatric procedures. The mean age and BMI were 38.7±8.3 years and 44 kg/m2, respectively. Out of the 202 primary SG performed, we encountered two cases of a staple-line leak (0.99%). This is the first reported case series of SG leaks from the Southeast Asia region. A summary of their characteristics, clinical presentation, subsequent management, and the outcome is discussed.Based on the latest available evidence from the literature, several methods may decrease staple-line leaks in SG. These include the use of a bougie size greater than 40 Fr, routine use of methylene blue test during surgery, beginning transection at 2–6 cm from the pylorus, mobilising the fundus before transection, and staying away from the GOJ at the last firing. Other methods include the proper alignment of the staple-line, control of staple-line bleeding, and performing staple-line reinforcement. The management of a staple-line leak remains challenging due to limited systematic, evidence-based literature being available. Therefore, a tailored approach is needed to manage this complication.

Eustachian tube functional assessment among patients with CSOM undergoing tympanoplasty surgery

<p class="abstract"><strong>Background:</strong> Pre-operative test of eustachian tube (ET) function is important for achieving a satisfactory result of tympanoplasty for CSOM patients. The saccharin test and methylene blue test seems to provide adequate information of the mucociliary function and patency of the ET. The aim was to study the ventilatory and mucociliary function of Eustachian tube in patients with chronic suppurative otitis media planned for tympanoplasty surgery and to assess the success rate of tympanoplasty in relation to the Eustachian tube function</p><p class="abstract"><strong>Methods:</strong> A prospective longitudinal study was conducted for a period of one year. Patients aged more than 15 years with features of chronic suppurative otitis media of either tubotympanic type or atticoantral type were included in the study. The total number of study subjects included in our study was 82 patients with CSOM. The ventilatory and the mucociliary functions of the auditory tube were assessed preoperatively using saccharin test and methylene blue test. All patients with CSOM underwent tympanoplasty surgery and the outcome of the surgery was assessed. </p><p class="abstract"><strong>Results:</strong> The overall success rate of tympanoplasty surgery was 76.8%. It was observed in our study that the success rate of tympanoplasty was higher among patients with normal eustachian tube function.</p><p class="abstract"><strong>Conclusions:</strong> Preoperative evaluation of eustachian tube function is mandatory for all the patients planned for tympanoplasty. Preoperative and intraoperative corrective measures should be taken in patients with partial and absent tubal function to improve the success rate of tympanoplasty surgeries.</p><p> </p>

The role of solvent on the formulation of graphene/polyporphyrin hybrid material versus photocatalytic activity

The influence of solvent used to prepare hybrid materials for photocatalytic applications formulated by cyclic bisphenol A/porphyrin copolyformal and graphene is here reported. To this purpose, the polymer is dissolved in different solvents [chloroform, tetrahydrofuran and dimethylformamide (DMF)] and used to impregnate via bath deposition 2D graphene. Depending on the nature of the solvent, polymer coats differently the graphene substrates producing peculiar SEM and AFM data. Microscopic and nanoscopic features of formulated materials were correlated with their photocatalytic activities by using methylene blue degradation test. Data collected under visible-light irradiation reveal as the best photodegradation performance was displayed by graphene coated with DMF copolyporphyrin solution.

Alternative Sands as Substitute for Natural Sand for the Construction Sector

While the need for sand in the construction sector is increasing, natural sand becomes scarce. On the other hand, several sand-like fractions out of industrial residues become available. This paper focusses on the potential use of these “alternative sands” as substitute for natural sand in the construction sector. The investigation included the study of the properties of alternative sands and a market research. In order to determine the properties, standard tests were performed such as the determination of the particle size distribution, the fineness modulus, the methylene blue test, determination of the density and the water-absorption. The particle size distribution of several fine recycled aggregates and of other fine fractions, derived from different producers, were compared to each other and to natural sand. This was to how alternative sands relate to natural sand and more specifically if they can be compared to natural sand and if they match the requirements of use of sand in constructional applications set by the standards and the standard specifications for road construction SB250. As a result, an overview table is made with the potential applications for each type of sand.

Synthesis and Evaluation of Novel TiO2-based Self-cleaning Coating Layer for Buildings

This research was carried out in order to analyse the potential of novel nitrogen-doped TiO2/SWCNT (N-doped TiO2/SWCNT) photocatalyst nanocomposites for pollutant removal that deposits on surfaces of buildings. In the present work, the procedure to fabricate this nanocomposite follows a simple method which is sol-gel synthesis method using titanium tetraisopropoxide (TTIP) and ammonia as the precursor. Different composition of TiO2 and SWCNT were used to achieve the optimum composition suitable for building surfaces as a self-cleaning coating. The fabricated dried sols were characterized by XRD to ensure TiO2’s anatase nanocrystalline structure was maintained even after doping. The morphology of these novel coatings was observed by FESEM. FESEM showed that uniform dispersion between TiO2 and SWCNT is present which exhibited a vine-like structure. Methylene blue degradation test was conducted to measure the photocatalytic efficiency of each coating. The highest degradation efficiency achieved was 72.43 %. Spin-coating method was used to deposit a thin layer of this coating on the glass substrate to inspect the water contact angle (WCA) of the as-prepared coatings. The coatings displayed a contact angle of 21.3 °proving that the wetting characteristic falls under hydrophilic category in which any sprinkled water is able to remove the dirt that deposits on the surface. Self-cleaning testing was carried out on glass substrates to further evaluate the coating layers. The coated substrates cleaned about 99 % of the dirt that deposited on its surface. These coatings could be utilized in various applications be it indoors or outdoors, for water remediation, energy saving panels and many potential fields.

Tumor-derived exosomes inhibit natural killer (NK) cell functions in the pre-metastatic niche of pancreatic cancer

The current chemotherapy of cystic echinococcosis (CE) is mainly based on the use of albendazole, and the results have been shown to be highly variable. Thus, new and more efficient treatment options are urgently needed. The goals of the current study were: a) to compare the ex vivo activity of flubendazole (FLBZ) and nitazoxanide (NTZ), given either separately or co-administered, against Echinococcus granulosus protoscoleces and cysts, b) to characterize the plasma disposition kinetics of FLBZ administered alone or combined with NTZ in mice; (c) to compare the in vivo activity of FLBZ and NTZ (either each alone or as a combined treatment) against secondary CE developed in mice. Ex vivo drug activity study: E. granulosus protoscoleces and cysts were incubated either with FLBZ, NTZ, or the FLBZ-NTZ combination. Protoscoleces and cyst viability was monitored by the methylene blue exclusion test and scanning electron microscopy (SEM). Pharmacokinetic study: Balb/C mice received FLBZ (5 mg/kg) orally either alone or co-administered with NTZ (100 mg/kg). Blood samples were collected up to 12 h post treatment and plasma analyzed for FLBZ/metabolites by HPLC. Clinical Efficacy study: following secondary infection, meaning i.p. injection of 1500 E. granulosus protoscoleces/animal (n = 40), the both drugs were administered by intragastric inoculation on a daily basis for a period of 25 days. Balb/C mice received FLBZ (5 mg/kg, twice a day) alone, NTZ (100 mg/kg, once daily) alone or a combination of both molecules (FLBZ, 5 mg/kg twice a day and NTZ, 100 mg/kg, once daily). Ten untreated animals were used as a control. All animals were killed and the weight of the cysts collected from each animal was recorded. The presence of NTZ did not markedly affect the FLBZ kinetic parameters in mice. FLBZ alone or combined with NTZ induced a reduction (P < 0.05) of cyst weight in comparison to the untreated control and NTZ-treated treated mice. The data obtained here indicate that NTZ did not affect hydatid cyst development in mice. Conversely, FLBZ shows an excellent efficacy against CE.

Methylene blue adsorption by TiO2-based nano-adsorbents: performance evaluation and kinetic study

This study deals with the synthesis of TiO2-based nano-adsorbents and their performance in methylene blue adsorption. Nano-adsorbents were made up of micronized powder of anatase TiO2 as a relatively low-cost precursor and a compound alkaline solution containing 5 mol of NaOH and 5 mol of KOH. To synthesize nano-adsorbents, the hydrothermal method was used at three different temperatures of 110, 155, and 200 °C and two calcination temperatures of 450 and 700 °C. The results of methylene blue adsorption tests indicated that the nano-structure synthesized at 155 °C was of maximum adsorption capacity and calcination process resulted in a significant decrease in adsorption capacity. This meso-porous nano-adsorbent was characterized by such techniques as Scanning Electrom Microscopy (SEM), Transmission Electron Microscopy (TEM), Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffractometry (XRD), Brunauer-Emmett-Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) analysis, and Fourier-Transform Infrared (FTIR) spectroscopy. Pseudo-first-order and pseudo-second-order adsorption kinetics, as well as the Weber and Morris model, were then used to conduct a kinetic study. The adsorption kinetics was also analyzed with three adsorption isotherm models—i.e., Langmuir, Temkin, and Freundlich. The obtained results suggested that the nano-adsorbent exhibiting the maximum adsorption capacity of 96 mg/g was well fitted to the pseudo-second-order model with a correlation coefficient of 0.9938. The findings also showed that the Freundlich model with a correlation coefficient of 0.9592 was the most compatible adsorption isotherm model for this nano-adsorbent.

Application of machine learning techniques to analyze anastomosis integrity after Total gastrectomy for prediction of clinical leakage

Intraoperative testing (IT) is used to confirm the integrity of gastrointestinal anastomosis. Clinical trials are available in the literature to support the fact that methylene blue can identify the leaks, and can thus help in minimizing the postoperative ratio of clinical leaks after total gastrectomy. In the recent literature, machine learning tools have been used very successfully to investigate the hypothesis of such complex clinical trials, where incomplete data is available. In this article, data obtained from a clinical study, is analyzed using machine learning, to verify whether or not the methylene blue test can accurately identify the leaks and to predict future outcomes. Furthermore, a comparative study based on most robust machine learning solvers is presented in this article to identify the most appropriate machine learning technique(s) for future applications. We have considered the data (over a period starting from Jan 2007 till Dec 2014) based on the total gastrostomies (TG), where methylene blue test was applied. Data was obtained from 198 patients having gastric cancer. Out of 198, 108 cases went through methylene blue test done by a nasojejunal tube while no test was carried out for rest of 90 cases. Intraoperative leakage rate, mortality rate, length of hospitalization and postoperative clinical leakage rate were the measured outcomes. To analyze the data and to predict whether there will be a leak or not, machine learning techniques were applied and the accuracy was compared. The main objective of this research is to predict the clinical leakage after applying methylene blue test on gastric cancer patients. This objective is successfully achieved by implementing six machine learning approaches. Case specific machine learning approaches are discussed to evaluate post clinical leakage rate and radio leakage rate. From our analysis, we have concluded that the prediction of intraoperative leak, post clinical leak and radio leak is possible with the aid of different machine learning techniques. An important conclusion drawn from this study is that a single machine learning technique can not accurately predict different stages of leak, since the accuracy of the technique depends on the specification of clinical data that varies from stage to stage.

Enhanced oil recovery and residues utilization of oil sludge through nitric acid pretreatment process

A cost-effective approach to realize both oil recovery and residues utilization of oil sludge (OS) was proposed. It was an oxidation/acidification-assisted pretreatment process, where nitric acid (HNO3) was employed before the procedure of pyrolysis. Effects of dosage and concentration of HNO3 on oil recovery rate from OS were studied. Under the optimal conditions (dosage:5 mL·(g−1 dried OS); concentration: 5 mol·L−1), method of this work demonstrated two advantages: higher oil recovery rate of 27.53% and lower residue pyrolysis temperature of 550 °C were obtained, respectively. Detailed mechanism of such results was investigated via characterizations and analyses, among which saturates, aromatics, resins and asphaltenes (SARA) contents and metals contents were associated with the phenomena. Both oxidation and acidification caused the change of component in OS, giving the two conclusions: more saturates produced and less metals contents left. Meantime, the adsorption behavior of pyrolysis residues was evaluated via methylene blue (MB) adsorption tests. The highest MB adsorption value reached to 89.25 mg·g-1 and Langmuir isotherm model was well fitted the equilibrium data. Overall, the oxidation/acidification-assisted pretreatment of OS through HNO3 can be suggested as an economic and effective option.

The Effects of Biochar Additive on the Properties of Geopolymer Materials

In this research, the effects of biochar additive on the properties of geopolymer materials were investigated. Normally, the geopolymer can be used for adsorption materials due to good ion exchange capacity. Biochar also has the application as an adsorption material for pollutant removal. Biochar particles were prepared from waste materials in pyrolysis condition. The geopolymer materials were prepared by mixing metakaolin and aluminium oxide in alkaline activator solutions of Na2SiO3and NaOH. Biochar was mixed with geopolymer by 0, 10, 20, and 30 % weight of binder. A NaOH concentration of 15 M, and Na2SiO3/NaOH ratios of 1.5 by weight were used. The density, porosity, and water absorption were measured. The phase formation, microstructure, and bonds of the sample were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The adsorption capacity of each sample was determined by methylene blue adsorption tests. The result of the removal efficiency of all samples shows high adsorption capacity (60-70 %). It should be interesting alternative materials used for remove of aqueous solution.

Effects and results of fibrin sealant use in laparoscopic sleeve gastrectomy

Background: Leakage and bleeding after LSG are very serious feared complications. The aim of this study was to review the clinical evidence after using fibrin sealant in standard LSG.Methods: Morbidly obese patients who underwent standard technique of LSG with using fibrin sealant were included in the study. Data concerning patient demographic variables [age, gender, body mass index (BMI, kg/m2), and comorbid conditions], previous surgeries, postoperative complications and postoperative readmissions were collected.Results: In total, 100 patients who underwent LSG, 51.6 % of the patients had obesity-related comorbid conditions with a BMI >35 kg/m². The mean age of the patients was 42 ± 13 years. All operations were completed laparoscopically. The mean operative time was 60 ± 12 min. No leakage was detected in the intra-operative methylene blue test. The mean hospital stay was 5 ± 2 days. Staple-line leakage, twist and stricture were not observed.No mortality were noted.Conclusion: This retrospective study shows that bariatric surgeons should consider using standard surgical surgery in LSG to reduce postoperative complications. Fibrin glue is a reliable and useful tool for strengthening the staple line and can prevent potential twist of the stomach.

The effect of air test and methylene blue perfusion test on detecting the quality of anastomosis during laparoscopic rectal cancer excision (Dixon)

Objective: To investigate the feasibility and safety of air test (AT) and methylene blue perfusion test (MBPT) to detect the quality of the anastomosis in laparoscopic rectal cancer excision (Dixon), and compare the two approaches. Methods: AT is performed by filling the pelvis with saline solution and insufflating the rectum with air through a size 22 G balloon catheter (Foley). MBPT is carried out by surrounding clean sponges around anastomosis and injecting methylene blue solution into the rectum as like as AT. The balloon catheter connected manometer,ensuring the pressure in rectum can reach 40 cmH(2)O during AT and MBPT. The presence of air bubbles and overt blue-stained spillage indicated anastomotic leaks which are were resolved during surgery. All 28 patients undergoing laparoscopic rectal excision received both AT and MBPT intraoperatively in a randomized fashion. The integrity of the anastomosis, postoperative vital signs, blood examination, drainage and postoperative imaging were analyzed. Results: All 28 patients received both tests successfully with no adverse event. MBPT Level 1 was detected in 15 cases, level 2 in 8 cases, level 3 in 5 cases. No MBPT level 4 was observed. AT level 1 was detected in 22 cases, level 2 in 5 cases, level 3 in 1 cases. No AT level 4 was founded. Three cases were diagnosed with postoperative anastomotic leakage (3/28, 10.71%), of which 2 cases were Grade B [definition and grading proposed by the international study group of rectal cancer (ISREC) in 2010]. One case was Grade C. The positive rate of MBPT was superior to AT (the McNemar testing, P<0.01). Conclusions: The two intraoperative tests are both technically feasible and safe. Compared to AT, MBPT has the advantage of localizing the leak site with a higher positive accuracy, and represents a promising standardized approach for intraoperative test of the anastomosis quality. Intraoperative repair is absolutely helpful for the level 3 and 4 intraoperative tests.

Alkaline Hydrothermal Synthesis, Characterization, and Photocatalytic Activity of TiO₂ Nanostructures: The Effect of Initial TiO₂ Phase.

One-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO₂ (P25) and anatase powders as precursor materials and strong NaOH solution as catalyzer. The prepared titanates were calcined, followed by protonation to produce TiO₂ nanostructures having enhanced photocatalytic and photovoltaic properties. The synthesized TiO₂ 1D nanostructures were characterized using field-emission scanning electron microscope, high-resolution electron microscope, X-ray diffraction analysis, and UV-Vis photospectroscopy to understand the effect of initial TiO₂ phase on morphological and crystallographic features, and bandgap. Methylene blue degradation test was applied to evaluate the photoactivity of the products obtained after different stages of the process. The findings indicate that 1D TiO₂ nanostructures form by different mechanisms from dissolved aggregates during hydrothermal process, depending on the crystal structure of the initial precursor used. Photocatalytic test results reveal that protonated titanates have considerable adsorption capability, while photocatalytic degradation depends on TiO₂ transformation.

Char properties and pollutant adsorption capability of oil palm shell using hydrothermal process

Hydrothermal carbonization (HTC) for lignocellulosic biomass has many advantages in terms of environmentally friendly, non-toxic, and low energy use. The products produced from HTC process can be used for various materials such as chemicals, adsorbents, energy, and agriculture fertilizer. In this study, HTC process has been done by using the oil palm shell (OPS). The purposes of this study were to evaluate the characteristics of the hydrochar, as well as to determine the effect of temperature and processing time on hydrochar properties resulting from the HTC process. The process was carried out using a temperature of 200 °C, 225 °C, and 250 °C, with a processing time of 4, 6, and 8 h. The ratio of biomass to water was 15:100 based on weight. The characterization that performed on the hydrochar and its raw OPS were elemental analysis, proximate analysis, Brunauer Emmett and Teller (BET), fourier transform infrared (FTIR), pyrolysis–gas chromatography–mass spectroscopy (Pyr–GC–MS), and X-ray diffraction (XRD). The determination of iodine number test, methylene blue number test, and some pollutants adsorption tests were also performed to characterize the product. The results showed that the surface area, fixed carbon, and carbon content of hydrochars were increased as compared with the raw OPS. The structure of hydrochar also differs with raw OPS structure based on XRD analysis. The hydrochar that produced by the temperature of 225 °C for 8 h selected as the best properties based on the determination of iodine, some gaseous pollutant adsorption, and surface area of materials.