Photocatalytic degradation of methylene blue over MIL-100(Fe)/GO composites: a performance and kinetic study

Adsorption coupled with photocatalytic degradation is proposed to fulfill the removal and thorough elimination of organic dyes.Herein,we report a facile hydrothermal synthesis of MIL-100(Fe)/GO photocatalysts.The adsorption and photocatalytic degradation process of methylene blue(MB)on MIL‐100(Fe)/GO composites were systematically studied from performance and kinetic perspectives.A possible adsorption‐photocatalytic degradation mechanism is proposed.The optimized 1M8G composite achieves 95%MB removal(60.8 mg/g)in 210 min and displays well recyclability over ten cycles.The obtained MB adsorption and degradation results are well fitted onto Langmuir isotherm and pseudo‐second order kinetic model.This study shed light on the design of MOFs based composites for water treatment.

Isotherm,kinetic and thermodynamic investigations of boron phosphide to remove methylene blue from aqueous solution

In this work,the boron phosphide(BP)was synthesized and used for the adsorptive removal of methylene blue(MB)dye from aqueous solutions.To determine the optimum adsorption conditions,studies were performed by varying parameters of temperature(298–328 K),pH(2–12),contact time(0–120 min),adsorbent dose(0.01–0.20 g/50 mL),and dye concentration(10–50 mg/L).Different isotherm and kinetic models were applied to the adsorption data.The linear correlations coefficient showed that the Langmuir isotherm best fits(R^(2)=0.9996).The maximum adsorption capacity of BP was obtained as 555.56 mg/g at 55℃and the removal rate reached up to 84.11%.Additionally,the pseudo-second-order kinetic model described the adsorption process best(R^(2)=0.9998).The thermodynamic studies represented that the adsorption occurred spontaneously(ΔG_(A)^(Θ)=−24.90 kJ/mol)and endothermically(ΔH_(A)^(Θ)=16.67 kJ/mol).The results showed that BP is an efficient adsorbent for removing cationic dyes from aqueous solutions.

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the core.Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate.Scanning electron microscopy images showed the core-shell structure.The core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the core.During the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the core.Adsorption tests showed that the coreshell structure had a larger adsorption capacity than the core alone.The shell effectively enhanced the adsorption capacity to methylene blue compared to the single core.Methylene blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed.

Silicalite-1 zeolite encapsulated Fe nanocatalyst for Fenton-like degradation of methylene blue

Encapsulation of Fe nanoparticles in zeolite is a promising way to significantly improve the catalytic activity and stability of Fe-based catalysts during the degradation process of organic pollutants.Herein,Fe nanocatalysts were encapsulated into silicalite-1(S-1)zeolite by using a ligand-protected method(with dicyandiamide(DCD)as a organic ligand)under direct hydrothermal synthesis condition.High-resolution transmission electron microscopy(HRTEM)results confirmed the high dispersion of Fe nanocatalysts which were successfully encapsulated within the voids among the primary particles of the S-1 zeolite.The developed S-1 zeolite encapsulated Fe nanocatalyst(Fe@S-1)exhibited significantly improved catalytic activity and reusability in the catalytic degradation process of methylene blue(MB).Specifically,the developed Fe0.021@S-1 catalyst showed high catalytic degradation activity,giving a high MB degradation efficiency of 100%in 30 min,outperformed the conventional impregnated catalyst(Fe/S-1).Moreover,the Fe@S-1 catalyst afforded an outstanding stability,showing only ca.7.9%activity loss after five cycling tests,while the Fe/S-1 catalyst presented a significantly activity loss of 50.9%after only three cycles.Notably,the encapsulation strategy enabled a relatively lower Fe loading in the Fe@S-1 catalyst in comparison with that of the Fe/S-1 catalyst,i.e.,0.35%vs.0.81%(mass).Radical scavenging experiments along with electron spin resonance(ESR)measurements confirmed that the major role of
OH in the MB degradation process.Specifically,Fe@S-1 catalyst with high molar ratio of[Fe(DCD)]Cl3 is beneficial to form Fe complexes/nanoclusters in the voids(which has large pore size of 1–2 nm)among the primary particles of the zeolite,and thus improving the diffusion and accessibility of reactants to Fe active sites,and thus exhibiting a relatively higher degradation efficiency.This work demonstrates that zeolite-encapsulated Fe nanocatalysts present potential applications in the advanced oxidation of wastewater treatment.

Silica Gel from Chemical Glass Bottle Waste as Adsorbent for Methylene Blue:Optimization Using BBD

This research focuses on the effective removal of methylene blue dye using silica gel synthesized from chemical glass bottle waste as an environmentally friendly and cost-effective adsorbent.The adsorption process was optimized using Box-Behnken Design(BBD)and Response Surface Methodology(RSM)to investigate the influence of pH(6;8 and 10),contact time(15;30 and 45 min),adsorbent mass(30;50 and 70 mg),and initial concentration(20;50 and 80 mg/L)of the adsorbate on the adsorption efficiency.The BBD was conducted using Google Colaboratory software,which encompassed 27 experiments with randomly assigned combinations.The silica gel synthesized from chemical glass bottle was characterized by XRD,FTIR,SEM-EDX and TEM.The adsorption result was measured by spectrophotometer UV-Vis.The optimized conditions resulted in a remarkable methylene blue removal efficiency of 99.41%.Characterization of the silica gel demonstrated amorphous morphology and prominent absorption bands characteristic of silica.The Langmuir isotherm model best described the adsorption behavior,revealing chemisorption with a monolayer coverage of methylene blue on the adsorbent surface,and a maximum adsorption capacity of 82.02 mg/g.Additionally,the pseudo-second-order kinetics model indicated a chemisorption mechanism during the adsorption process.The findings highlight the potential of silica gel from chemical glass bottle waste as a promising adsorbent for wastewater treatment,offering economic and environmental benefits.Further investigations can explore its scalability,regenerability,and reusability for industrial-scale applications.

Investigation of photoelectrocatalytic degradation mechanism of methylene blue by a-Fe_(2)O_(3) nanorods array

Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.

Surface Modification of Bamboo-based Activated Carbon for Methylene Blue Removal

The feasibility of biomass-based activated carbon has received tremendous attention owing to its excellent properties,such as insensitivity,good adsorption performance,and potential to reduce the strong dependence on non-reproducible precursors.In this study,bamboo-based activated carbon(BAC)was used as the raw material for methylene blue(MB)removal.Cetyltrimethylammonium bromide(CTAB),sodium dodecyl sulfate(SDS),and sodium dodecylbenzene sulfonate(SDBS)were used as BAC surface modifiers.The morphologies and structures of the samples were characterized.In addition,the effects of the surfactant type and concentration on the adsorption-based removal of MB from aqueous solutions by the modified BAC were systematically investigated.For the 0.2 g/L MB solution,the MB removal rate reached 99.7%when the concentration of CTAB was 0.25 g/L.Moreover,the kinetic model curve of 0.25 g/L CTAB-modified BAC(CAC)was consistent with the Freundlich isotherm model.This research work enriches the technical pathway of modification and application of activated carbon,which is not only beneficial for realizing the high-value utilization of biomass bamboo resources but also can play an active role in guiding the treatment of MB-containing wastewater.

Understanding association between methylene blue dye and biosorbent: Palmyrah sprout casing in adsorption process in aqueous phase

Water pollution caused by industrial dyes has become a severe problem in the modern world. Biosorbents can be used in an eco-friendly manner to remove industrial dyes. In this study, five biosorbents were selected: palmyrah sprout casing (PSC), manioc peel, lime peel, king coconut husk, and coconut kernel. Batch adsorption experiments were conducted to identify the best biosorbent with the highest ability to adsorb methylene blue (MB) from wastewater. The detailed mechanisms of PSC used in the adsorptive removal of MB in aqueous phase were investigated. Of the five biosorbents, PSC exhibited the best removal performance with an adsorption capacity at equilibrium (qe) of 27.67 mg/g. The qe values of lime peel, king coconut husk, manioc peel, and coconut kernel were 24.25 mg/g, 15.29 mg/g, 10.84 mg/g, and 7.06 mg/g, respectively. To explain the mechanisms of MB adsorption with the selected biosorbents, the Fourier transform infrared (FTIR) spectrometry and X-ray diffraction (XRD) analyses were performed to characterize functional properties, and isotherm, kinetic, rate-limiting, and thermodynamic analyses were conducted. The FTIR analysis revealed that different biosorbents had different functional properties on their adsorptive surfaces. The FTIR and XRD results obtained before and after MB adsorption with PSC indicated that the surface functional groups of carbonyl and hydroxyl actively participated in the removal process. According to the isotherm analysis, monolayer adsorption was observed with the Langmuir model with a determination coefficient of 0.998. The duration to reach the maximum adsorption capacity for MB adsorption with PSC was 120 min, and the adsorption process was exothermic due to the negative enthalpy change (-9.950 kJ/mol). Moreover, the boundary layer thickness and intraparticle diffusion were the rate-limiting factors in the adsorption process. As a new biosorbent for MB adsorption, PSC could be used in activated carbon production to enhance the performance of dye removal.

Enhanced photocatalytic performance of iron oxides@HTCC fabricated from zinc extraction tailings for methylene blue degradation:Investigation of the photocatalytic mechanism

Photocatalytic processes are efficient methods to solve water contamination problems,especially considering dyeing wastewater disposal.However,high-efficiency photocatalysts are usually very expensive and have the risk of heavy metal pollution.Recently,an iron oxides@hydrothermal carbonation carbon(HTCC)heterogeneous catalyst was prepared by our group through co-hydrothermal treatment of carbohydrates and zinc extraction tailings of converter dust.Herein,the catalytic performance of the iron oxides@HTCC was verified by a nonbiodegradable dye,methylene blue(MB),and the catalytic mechanism was deduced from theoretical simulations and spectroscopic measurements.The iron oxides@HTCC showed an excellent synergy between photocatalysis and Fenton-like reactions.Under visible-light illumination,the iron oxides@HTCC could be excited to generate electrons and holes,reacting with H_(2)O_(2)to produce·OH radicals to oxidize and decompose organic pollutants.The removal efficiency of methylene blue over iron oxides@HTCC at 140 min was 2.86 times that of HTCC.The enhanced catalytic performance was attributed to the advantages of iron oxides modification:(1)promoting the excitation induced by photons;(2)improving the charge transfer.Furthermore,the iron oxides@HTCC showed high catalytic activity in a wide pH value range of 2.3-10.4,and the MB removal efficiency remained higher than 95% after the iron oxides@HTCC was recycled 4 times.The magnetically recyclable iron oxides@HTCC may provide a solution for the treatment of wastewater from the textile industry.

Methylene blue intercalated vanadium oxide with synergistic energy storage mechanism for highly efficient aqueous zinc ion batteries

With the rise of aqueous multivalent rechargeable batteries,inorganic-organic hybrid cathodes have attracted more and more attention due to the complement of each other’s advantages.Herein,a strategy of designing hybrid cathode is adopted for high efficient aqueous zinc-ion batteries(AZIBs).Methylene blue(MB)intercalated vanadium oxide(HVO-MB)was synthesized through sol-gel and ion exchange method.Compared with other organic-inorganic intercalation cathode,not only can the MB intercalation enlarge the HVO interlayer spacing to improve ion mobility,but also provide coordination reactions with the Zn^(2+)to enhance the intrinsic electrochemical reaction kinetics of the hybrid electrode.As a key component for the cathode of AZIBs,HVO-MB contributes a specific capacity of 418 mA h g^(-1) at 0.1 A g^(-1),high rate capability(243 mA h g^(-1) at 5 A g^(-1))and extraordinary stability(88%of capacity retention after 2000cycles at a high current density of 5 A g^(-1))in 3 M Zn(CF_(3)SO_(3))_(2) aqueous electrolyte.The electrochemical kinetics reveals HVO-MB characterized with large pseudocapacitance charge storage behavior due to the fast ion migration provided by the coordination reaction and expanded interlayer distance.Furthermore,a mixed energy storage mechanism involving Zn^(2+)insertion and coordination reaction is confirmed by various ex-situ characterization.Thus,this work opens up a new path for constructing the high performance cathode of AZIBs through organic-inorganic hybridization.

Enhanced photocatalytic activity of methylene blue using heterojunction Ag@TiO_(2)nanocomposite:Mechanistic and optimization study

The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were pH,UV-irradiation time,temperature,catalytic dosage,and concentration of MB.The results showed that 0.2×10^(3) g·ml^(-1))of the catalytic dose caused the Ag@TiO_(2)adsorption to degrade by 96.67%with darks and UV exposure.Using the Langmuir-Hinshelwood model to determine the kinetic,the Ag@TiO_(2)displays a greater kinetic rate than TiO_(2)and silver nanoparticle(AgNPs).The photocatalytic degradation of MB,which is an endothermic reaction involving all catalysts,is shown by the thermodynamic parameter to have the positive value of enthalpy(ΔH°).The enthalpies observed were Ag@TiO_(2)(126.80 kJ·mol^(-1))<AgNPs(354.47 kJ·mol^(-1))<TiO_(2)(430.04 kJ·mol^(-1)).Ascorbic acid(·OH scavenger),2-propanol(·O_(2)scavenger),and ammonium oxalate(AO)(hole h+scavenger)were employed to conduct the scavenger effects.The Ag@TiO_(2)demonstrated a reduction in MB degradation when combined with 2-propanol,and this clearly demonstrated that,in contrast to hydroxyl radicals(·OH)and holeh scavengers,superoxide radical anion(O_(2)scavenger)plays a significant role in MB degradation.Utilizing density functional theory(DFT)to elucidate the mechanism and B3LYP/6-311+G(d,p)level optimization,the degradation-adsorption process was explained.When the N-N,C-N or C-C bonds were severed,the Fukui faction was demonstrated for nucleophilic,electrophilic,and radical attack.

Optimizing Methylene Blue Removal from Textile Effluents: Comparative Study of Adsorption Efficiency Using Raw and Activated Carbon Derived from Gmelina Wood Wastes

This research investigates the efficacy of activated Gmelina Wood Sawdust (GWS) as an adsorbent for the removal of methylene blue (MB) dye from aqueous solutions, in comparison with raw GWS. The study employs laboratory experiments to assess the percentage of dye removal across various temperature and pH conditions. The adsorption process is scrutinized under different parameters, encompassing contact time, initial dye concentration, adsorbent dosage, temperature, and pH. Results demonstrate that activated GWS surpasses its raw counterpart, showcasing superior MB dye removal percentages. Extended contact times increased initial dye concentrations, and higher adsorbent dosages contribute positively to removal efficiency, while temperature exhibits an inverse relationship with dye removal. Optimal adsorption occurs at a pH of 7.0, aligning with the adsorbent’s zero-point charge (pHzpc), underscoring the role of surface charge in the adsorption process. This study underscores the potential of activated GWS as an economical and promising adsorbent material for addressing pollutants. Furthermore, the utilization of activated carbon derived from abundant agricultural waste underscores an environmentally conscious approach to adsorption applications. The ability to tailor the size and properties of activated carbon particles opens avenues for optimizing adsorption capabilities, thereby presenting opportunities for enhanced water treatment solutions.

Desorption of Methylene Blue Adsorbed on Activated Carbon from Cocoa Pod Shell

Environmental protection has become a concern for the world. For this reason, the objective of this work is to remove methylene blue adsorbed on activated carbon. The coal used comes from cocoa pod shells. Before pyrolysis, the shells were ground, sieved and impregnated with orthophosphoric acid. Before desorption, the activated carbons were initially saturated with MB. These saturated coals were brought into contact with a sodium chloride (NaCl) solution and then stirred. The evolution of the resorbed MB concentration was monitored by spectrophotometry. The desorption tests showed a remarkable elimination from the first 10 minutes. The desorption kinetics comprises two phases: a rapid kinetics between 0 and 30 minutes and a slow kinetics between 30 and 60 minutes. The desorption of the dye reaches a concentration aqual to 0.84 mg/l at pH = 4 at temperature = 80°C. For modeling, the coefficient of the Langmuir II model is greater than or equal to O.9893. The model of Langmuir III is less than or equal to 0.9373. The Freundlich model coefficient is 0.9842 or less. The desorption is thefore carried out on energy-homogeneous adsorption sites and without any interaction between the adsorbed cations of the dye. Experimental parameters such as pH, temperature and concentration of sodium chloride (NaCl) solution influence the desorption of MB. And the model of Langmuir II describes well the process of desorption of the MB.

Percutaneous transhepatic cholangial drainage-guided methylene blue for fistulotomy using dual-knife for bile duct intubation: A case report

BACKGROUND Difficult bile duct intubation is a big challenge for endoscopists during endoscopic retrograde cholangiopancreatography(ERCP)procedure.We report a case of percutaneous transhepatic cholangial drainage(PTCD)-guided methylene blue for fistulotomy using dual-knife for bile duct intubation.CASE SUMMARY A 50-year-old male patient had developed obstructive jaundice,and ERCP procedure need to be performed to treat the obstructive jaundice.But intubation cannot be performed if the duodenal papilla cannot be identified because of previous surgery for a perforated descending duodenal diverticulum.We used PTCD-guided methylene blue to identify the intramural common bile duct before dual-knife fistulotomy,and bile duct intubation was successfully completed.CONCLUSION The method that combing methylene blue and dual-knife fistulotomy to achieve bile duct intubation during difficult ERCP is safe and effective.

Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly(acrylic acid)/vermiculite hydrogel composites

A series of chitosan-g-poly （acrylic acid）/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the effect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue （MB） from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly （acrylic acid） polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.

TiO_2/polyaniline composites:An efficient photocatalyst for the degradation of methylene blue under natural light

Polyaniline （PAn） sensitized nanocrystalline TiO2 composites （TiO2/PAn） were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue （MB）. The results showed that PAn was able to sensitize TiO2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light （λ： 190 ～ 800 nm）, whereas pure TiO2 absorbed ultraviolet light only （λ 〈 380 nm）. Under the irradiation of natural light, MB could be degraded more efficiently on the TiO2/PAn composites than on the TiO2 Furthermore, it could be easily separated from the solution by simple sedimentation.

Methylene blue enhances polyethylene glycol-fusion repair of completely severed rat sciatic nerves

Complete transection of peripheral mixed nerves immediately produces loss of sensory perception,muscle contractions and voluntary behavior mediated by the severed distal axons.In contrast to natural regeneration(~1 mm/d)of proximal axons that may eventually reinnervate denervated targets,re-innervation is restored within minutes by PEG-fusion that consists of neurorrhaphy and a sequence of well specified hypo-and isotonic calcium-free or calcium-containing solutions,the anti-oxidant methylene blue(MB)and the membrane fusogen polyethylene glycol(PEG).In this study,we examined the relative efficacy of PEG-fusion with no MB(0%),0.5%MB,or 1%MB on the recovery of voluntary behaviors by female Sprague-Dawley rats with a complete mid-thigh severance of their sciatic nerve bathed in extracellular fluid or calcium-containing isotonic saline.The recovery of voluntary behaviors is the most relevant measure of success of any technique to repair peripheral nerve injuries.We assessed recovery by the sciatic functional index,a commonly used measure of voluntary hindlimb behaviors following complete sciatic transections.We reported that both 1%MB and 0.5%MB in sterile distilled water in our PEG-fusion protocol with neurorrhaphy significantly increased the rate and extent of behavioral recovery compared to PEG plus neurorrhaphy alone.Furthermore,0.5%MB was as effective as 1%MB in voluntary behavioral recovery as assessed by the sciatic functional index.Since sterile 1%MB is no longer clinically available,we therefore recommend that 0.5%MB be included in upcoming human clinical trials to evaluate the safety and efficacy of PEG-fusion.All animal procedures were approved by the University of Texas Institutional Animal Care and Use Committee(AUP-2019-00225)on September 9,2020.

Equilibrium,Kinetics and Thermodynamics of the Adsorption of Methylene Blue onto a Metal-Organic Frameworks Material,Copper Coordination Polymer with Dithiooxamide

The equilibrium, kinetics and thermodynamics of the adsorption of methylene blue( MB) from aqueous solution onto copper coordination polymer with dithiooxamide( H2dtoaCu),one of the metal-organic frameworks( MOFs),were investigated in a batch adsorption system as a function of initial pH, adsorbent concentration, contact time, initial dye concentration, and temperature. The Langmuir, Freundlich, and DubininRadushkevich( D-R) isotherm models were used for modeling the adsorption equilibrium. It was found that Langmuir model yielded a much better fit than the Freundlich model under different temperatures. The maximum monolayer adsorption capacities of MB were 192. 98,229. 86,and 297. 38 mg /g at 298,308,and 318 K,respectively. The calculated mean adsorption energy( 8. 26-11. 04 kJ /mol) using D-R model indicated that the adsorption process might take place by chemical adsorption mechanism.Otherwise,the kinetic studies revealed that the adsorption process could be well explained by pseudo-second-order rate kinetics and intraparticle diffusion was not the rate-limiting step.Thermodynamic studies indicated that this system was feasible,spontaneous,and endothermic process. Based on these studies,H2dtoaCu can be considered as a potential adsorbent for the removal of MB from aqueous solution.

One-pot synthesis of poly vinyl alcohol(PVA) supported silver nanoparticles and its efficiency in catalytic reduction of methylene blue

Stable silver nanoparticles were synthesized using polyvinyl alcohol （PVA） as reducing and capping agent. The method of steric stabilization was adopted for the incorporation of silver nanoparticles in the polymer matrix. The successful incorporation of silver nanoparticles in a PVA matrix was confirmed by UV–Visible spectroscopy, transmission electron microscopy （TEM） and Fourier transform infrared （FT-IR） spectroscopy. The synthesized silver nanoparticles were characterized by a peak at 426 nm in the UV–Vis spectrum. TEM studies showed the formation of spherical shaped silver nanoparticles of 10-13 nm, following the reduction by UV irradiation. Catalytic properties were studied by means of UV-Visible spectroscopic analysis. The synthesized silver nanoparticles exhibited good catalytic properties in the reduction of methylene blue.

Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro

AIM:To investigate whether activated carbon nanoparticles suspension(ACNS) or methylene blue(MB) can increase the detected number of lymph nodes in colorectal cancer.METHODS:Sixty-seven of 72 colorectal cancer patients treated at our hospital fulfilled the inclusion criteria of the study which was conducted from December 2010 to February 2012.Seven patients refused to participate.Eventually,60 patients were included,and randomly assigned to three groups(20 in each group):ACNS group(group A),MB group(group B) and non-stained conventional surgical group(group C).In group A,patients received subserosal injection of 1 mL ACNS in a 4-quadrant region around the mass.In group B,the main artery of specimen was identified and isolated after the specimen was removed,and 2 mL MB was slowly injected into the isolated,stretched and fixed vessel.In group C,no ACNS and MB were injected.All the mesentery lymph nodes were isolated and removed systematically by visually inspecting and palpating the adipose tissue.RESULTS:No difference was observed among the three groups in age,gender,tumor location,tumor diameter,T-stage,degree of differentiation,postoperative complications and peritoneal drainage retention time.The total number of detected lymph nodes was 535,476 and 223 in the three groups,respectively.The mean number of detected lymph nodes per patient was significantly higher in group A than in group C(26.8 ± 8.4 vs 12.2 ± 3.2,P < 0.001).Similarly,there were significantly more lymph nodes detected in group B than in group C(23.8 ± 6.9 vs 12.2 ± 3.2,P < 0.001).However,there was no significant difference between group A and group B.There were 50,46 and 32 metastatic lymph nodes dissected in 13 patients of group A,10 patients of group B and 11 patients of group C,without significant differences among the three groups.Eleven of the 60 patients had insufficient number of detected lymph nodes(< 12).Only one patient with T 4a rectal cancer had 10 lymph nodes detected in group B,the other 10 patients were all from group C.Based on the different diameter categories,the number of detected lymph nodes in groups A and B was significantly higher than in group C.However,there was no statistically significant difference between group A and group B.The metastatic lymph nodes were not significant different among the three groups.Similarly,tumor location,T stage and tumor differentiation did not affect the staining results.Body mass index was a minor influencing factor in the two different staining methods.The stained lymph nodes can easily be identified from the mesenteric adipose tissues,and the staining time for lymph nodes was not significantly different compared with unstained group.None of the patients in groups A and B had drug-related complications.CONCLUSION:Both activated carbon nanoparticles suspension in vivo and methylene blue in vitro can be used as tracers to increase the detected number of lymph nodes in colorectal cancer.