A green cross-linking method for the preparation of renewable threedimensional graphene sponges for efficient adsorption of Congo red dye

Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.

Hierarchical porous MgBO_2(OH) microspheres: Hydrothermal synthesis,thermal decomposition, and application as adsorbents for Congo red removal

A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

A Novel Adsorbent Prepared by Aluminum-Containing Waste Residue and Its Application for Congo Red Wastewater Decolorization

Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)2. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration of 100 mg/L and initial pH = 5, and the adsorption time was 40 min, the CR removal efficiency was 98.41%. The adsorption trend of CR conformed to the second-order kinetics, and the adsorption isotherm follows the Freundlich isotherm model. Compared with RAS, MAS has a larger pore volume and specific surface area. The mechanism of action of MAS on CR was the interaction between membrane diffusion and internal diffusion, and the adsorption rate during the membrane diffusion was the fastest.

Congophilic fibrils in the glomeruli with polyclonal immunoglobulin gamma staining-another cause for diagnostic overlap:A case report

BACKGROUND Glomerulopathy with fibrillary deposits is not uncommon in routine nephropathology practice,with amyloidosis and fibrillary glomerulonephritis being the two most frequently encountered entities.Renal amyloid heavy and light chain(AHL)is relatively uncommon and its biopsy diagnosis is usually limited to cases that show strong equivalent staining for a single immunoglobulin(Ig)heavy chain and a single light chain,further supported by mass spectrometry(MS)and serum studies for monoclonal protein.But polyclonal light chain staining can pose a challenge.CASE SUMMARY Herein we present a challenging case of renal AHL with polyclonal and polytypic Ig gamma(IgG)staining pattern by immunofluorescence.The patient is a 62-yearold Caucasian male who presented to an outside institution with a serum creatinine of up to 8.1 mg/dL and nephrotic range proteinuria.Despite the finding of a polyclonal and polytypic staining pattern on immunofluorescence,ultrastructural study of the renal biopsy demonstrated the presence of fibrils with a mean diameter of 10 nm.Congo red was positive while DNAJB9 was negative.MS suggested a diagnosis of amyloid AHL type with IgG and lambda,but kappa light chains were also present supporting the immunofluorescence staining results.Serum immunofixation studies demonstrated IgG lambda monoclonal spike.The patient was started on chemotherapy.The chronic renal injury however was quite advanced and he ended up needing dialysis shortly after.CONCLUSION Tissue diagnosis of AHL amyloid can be tricky.Thorough confirmation using other available diagnostic techniques is recommended in such cases.

Design, Microwave Assisted Synthesis of Some Schiff Bases Derivatives of Congo Red and Conventional Preparation of Their Structurally Reversed Analogous Compounds

This work contributes to the improvement of the azo group which has outstanding electron donating capability and serves as excellent ligands in the field of coordination chemistry. The authors of this research deal with the microwave irradiation synthesis of some new Schiff bases derived from the biologically effective and photoactive Congo red [Ia-g]. The design and preparation of the structurally reversed analogous compounds to the above compounds [IIIa-d] were accomplished using the conventional chemical methods by keeping the benzidine moiety of Congo red as the nucleus of the synthesized compounds, doubling the number of the azo groups and inverting the way of their conjugation order with the azomethine groups. The structures of the newly prepared compounds were established on the basis of their FTIR and H1 NMR spectral data.

Fabrication of Congo Red/Oxidized Porous Silicon (CR/OPS) pH-Sensors

The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etching of silicon in alkaline solution using wetting agents is discussed. Transformation of crystallographic plane of n-Si (211) to nPSi (100) has occurred on using n-propanol as wetting agent. The rate of pore formation was 0.02478 - 0.02827 μm/min, which was heavily dependent upon the concentration of the etchant containing wetting agents, allowing patterned porous silicon formation through selective doping of the substrate. A particle size of 15 nm for porous nano-silicon was calculated from the XRD data. Porosity of PS layers is about 10%. Pore diameter and porous layer thickness are 0.0614 nm and 16 μm, respectively. The energy gap of the produced porous silicon is 3.3 eV. Furthermore, the combination of PS with Congo Red, which are nanostructured due to their deposition within the porous matrix is discussed. Such nano compounds offer broad avenue of new and interesting properties depending on the involved materials as well as on their morphology. Chemical route was utilized as the host material to achieve pores filling. They were impregnated with Congo Red, which gave good results for the porous silicon as a promising pH sensor.

植物补光用In^(3+)掺杂Zn_(3)Ga_(2)Ge_(2)O_(10)∶Cr^(3+)远红光发光材料的性能研究

采用高温固相法制备了Cr^(3+)掺杂的远红光荧光粉,并通过引入In^(3+)对Zn_(3)Ga_(2)Ge_(2)O_(10)∶Cr^(3+)发光特性进行了调控。通过XRD对Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)(摩尔分数)的晶体结构进行了分析。利用室温荧光光谱和热释光光谱分析了Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)的发光特性,其发射光谱由^(4)T_(2)(^(4)F)→^(4)A_(2)和^(2)E→^(4)A_(2)跃迁的705、721 nm两发光峰叠加而成。随着Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)中In^(3+)掺杂浓度增加,材料发射光谱呈现展宽的现象,这是Cr^(3+)所处晶体场环境的改变导致了晶体场劈裂程度的变化。光谱展宽后荧光材料的发光特性与植物中光敏色素吸收谱更加匹配,因此其有望应用于植物照明领域。此外,随着In^(3+)掺杂浓度增加,荧光材料表现出红色长余辉现象,并且余辉时间与In^(3+)掺杂浓度有关。

Preparation and characterization of MWCNTs/LDHs nanohybrids for removal of Congo red from aqueous solution

The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by using XRD, FT-IR, SEM/EDX, TGA and BET. XRD and SEM studies proved that MWCNTs phases did not enter into the interlayers of LDHs, they dispersed over the LDHs surface homogeneously. BET results showed that MWCNTs/LDHs possessed hierarchically porous nanostructure with large surface area （124.974 m^2/g） and great pore volume （0.604 cm^3/g）. Batch experiments were conducted to study the adsorption efficiency of Congo red （CR）. It was worthy to note that MWCNTs/LDHs exhibited excellent adsorption performance with the maximum CR adsorption capacity of 595.8 mg/g in weak acidic environment. The adsorption kinetics and isotherm parameters can be well described by the pseudo-second-order and the Langmuir isotherm models, respectively. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic.

Discoloration of Congo Red by Rod-Plate Dielectric Barrier Discharge Processes at Atmospheric Pressure

A dielectric barrier discharge （DBD） reactor with a rod-plate electrode configuration was used for the oxidative decomposition of Congo red dye in an aqueous solution. Plasma was generated in the gas space above the water interface under atmospheric pressure. Discharge characteristics were analyzed by voltage-current waveforms. Effects of applied voltage, initial conductivity, and initial concentration were also analyzed. Congo red discoloration increased with increased applied voltage and decreased conductivity. The initial conductivity significantly influenced the Congo red discoloration. Under the same conditions, the highest discoloration rate was obtained at 25 mg/L. The presence of ferrous ions in the solutions had a substantial positive effect on Fenton dye degradation and flocculation. At an applied voltage of 20 kV, about 100% of dye was degraded after 4 min of Fe^2＋/DBD treatment. Results showed that adding a certain dosage of hydrogen peroxide to the wastewater could enhance the discoloration rate. Possible pathways of Congo red discoloration by DBD plasma were proposed based on GC/MS, FTIR, and UV-vis spectroscopy analyses.

Adsorption of congo red on mesoporous activated carbon prepared by CO2 physical activation

This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide.Central composite design was applied to conduct the experiments at different levels by altering three operating parameters.Activation temperature(766-934℃),CO2 flow rate(0.8-2.8 L·min^-1)and activation time(5-55 min)were the variables examined in this study.The effect of parameters on the specific surface area,total pore volume and burn-out rate of activated carbon was studied,and the influential parameters of methylene blue adsorption value were identified employing analysis of variance.The optimum conditions for maximum methylene blue adsorption value were:activation temperature=900℃,activation time=29.05 min and CO2 flow rate=1.8 L·min(-1).The activated carbon produced under optimum conditions was characterized by BET,FTIR and SEM.The adsorption behavior on congo red was studied.The effect of parameters on the adsorbent dosage,temperature,PH and initial congo red concentration was investigated.The adsorption properties of the activated carbon were investigated by kinetics.The equilibrium removal rate and maximum adsorption capacity reaches up to 94.72%,234 mg·g^-1,respectively when initial congo red concentration is 200 mg·L^-1 under adsorbent dosage(0.8 g·L^-1),temperature(30℃),PH7.

Preparation and Characterization of Mg/Al/Fe Hydrotalcite with Superb Absorption Capacity toward Congo Red

Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-LDH was investigated by X-ray diffraction, field emission scanning electron microscopy, Fourier transformed infrared spectra, thermogravimetric analysis, and N2 adsorption-desorption.The morphology of MAF-LDH1 is petal-like with the size of 400-500 nm and the thickness about 10-20 nm. The adsorption performance of the samples was evaluated by absorption of the Congo red(CR) solutions. Compared with Mg/Al layered double hydroxide(MA-LDH), the maximum adsorption capacities of the MAF-LDH1 samples were 943.4 mg/g which was greatly enhanced. Furthermore, after seven cycling tests, the adsorption performance was still up to 90%. Theoretical calculation results revealed that the adsorption process was spontaneous and followed the pseudo-second-order kinetic model and Freundlich model. This work provides a promising alternative strategy to enhance the adsorptive properties of hydrotalcite-like materials.

Radio Frequency Underwater Discharge Operation and Its Application to Congo Red Degradation

Radio frequency （RF） underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as .OH, .O, .H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conduc- tivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy （FT-IR） and Liquid Chromatography-Mass Spectrometry （LC- MS） data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.

Synthesis and characterization of carboxymethyl cellulose/organic montmorillonite nanocomposites and its adsorption behavior for Congo Red dye

A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared （FT-IR） spectrophotometer, X-ray diffraction （XRD） method, transmission electron microscope （TEM）, scanning electron microscope （SEM）, and thermal gravimetric （TG） analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red （CR） dye were investigated by controlling the amount ofhexadecyl trimethyl ammonium bromide （CTAB）, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 rag/g, with the amount of CTAB being 1.0 cation exchange capacity （CEC） of MMT, the weight ratio of CMC to OMMT being l：l, the reaction time being 6 h, and the reaction temperature being 60~C. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.

One-step hydrothermal synthesis of Sn-doped α-Fe_(2)O_(3) nanoparticles for enhanced photocatalytic degradation of Congo red

We report on the synthesis of Sn-doped hematite nanoparticles(Sn-α-Fe_(2)O_(3) NPs)by the hydrothermal method.The prepared Sn-α-Fe_(2)O_(3) NPs had a highly pure and well crystalline rhombohedral phase with an average particle size of 41.4 nm.The optical properties of as-synthesizedα-Fe_(2)O_(3) NPs show a higher bandgap energy(2.40-2.57 eV)than that of pure bulkα-Fe_(2)O_(3)(2.1 eV).By doping Sn intoα-Fe_(2)O_(3) NPs,the Sn-doped hematite was observed a redshift toward a long wavelength with in-creasing Sn concentration from 0%to 4.0%.The photocatalytic activity of Sn-dopedα-Fe_(2)O_(3) NPs was evaluated by Congo red(CR)dye degradation.The degradation efficiency of CR dye using Sn-α-Fe_(2)O_(3) NPs catalyst is higher than that of pureα-Fe_(2)O_(3) NPs.The highest degradation efficiency of CR dye was 97.8%using 2.5%Sn-dopedα-Fe_(2)O_(3) NPs catalyst under visible-light irradi-ation.These results suggest that the synthesized Sn-dopedα-Fe_(2)O_(3) nanoparticles might be a suitable approach to develop a photocatalytic degradation of toxic inorganic dye in wastewater.

Adsorption Isotherms and Kinetic Studies of Congo-Red Removal from Waste Water Using Activated Carbon Prepared from Jujube Seed

In this study, adsorption of Congo red dye onto activated carbon prepared from Jujube (Ziziphus Mauritiania) seeds with phosphoric acid as the activating agent was investigated. Batch adsorption studies were carried out to study the influence of contact time, adsorbent dosage and initial dye concentration on the adsorption. The data was analysed using pseudo-first order and pseudo-second order kinetic models. The pseudo-second order kinetic model was found to describe the adsorption more effectively with a perfect correlation coefficient of unity. The rate constant, K was obtained as 0.182 (g/mg min) and the calculated qe (9.81) is very close to the experimental value (9.78). A high correlation coefficient obtained when the data was analysed with the intraparticle diffusion rate equation, revealed the presence of intraparticle diffusion in the adsorption process even though it is not the sole controlling step as shown by the value of the intercept (C ≠ 0). Isotherm studies showed that there is high correlation in each case when the data was modelled with Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherm models but the best fit was obtained with the Freundlich model with R2 = 0.9991, adsorption capacity, KF = 19.73 (mg/g)(mg/L)1/n and n = 1.563 indicating the adsorption is favourable and occurs on a heterogeneous surface by multilayer. The study showed that activated carbon from jujube seeds is an effective adsorbent for the removal of Congo red dye from solution.

Comparative Isotherms Studies on Adsorptive Removal of Congo Red from Wastewater by Watermelon Rinds and Neem-Tree Leaves

Equilibrium adsorption studies for detoxification of Congo Red (CR) dye from single component model wastewater by powdered watermelon rinds and neem leaves adsorbents were carried out with the view to test the applicability of the adsorption process to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Harkins-Jura isotherm models. The values of correlation coefficient, R2 (0.9359 - 0.9998), showed that all the experimental data fitted the linear plots of the tested isotherm models. Dubinin-Radushkevich’s monolayer maximum adsorption capacity qD (20.72 - 26.06 mg/g) is better than Langmuir’s qm (18.62 - 24.75 mg/g) for both adsorbents with the capacities higher for adsorption on watermelon rind than on neem leaves. Values of Langmuir separation factor (RL) suggest unfavourable adsorption processes (i.e. chemisorption) of the dye on both the adsorbents, while Freundlich constant (nF) indicates unfavourable process only for CR adsorption onto neem leaves. The Dubinin-Radushkevich’s mean free energy of adsorption, E (0.29 - 0.32 kJ/mol), suggests physical adsorption processes. Values for Temkin’s heat of adsorption, bT (-0.95 to 0.74 kJ/mol), also show physical adsorption process.

Facile Synthesis and Characterization of Nanoporous NiO with Folic Acid as Photodegredation Catalyst for Congo Red

In this study nanoporous NiO was prepared using Ni(CH3COO)2,4H2O, folic acid and water as starting material, template and solvent respectively, by sol gel method followed by calcination at 400℃. The solid product was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) Fourier transform infrared (FT-IR) and photoluminescence (PL) techniques. The particle size of the nanoparticles estimated by XRD was in good agreement with the particle size obtained by TEM analysis (4-5nm). It was also found that the prepared nanoporous NiO show very good activity for photodegredation of dye organic pollutants such as Congo red (91%) during 1.5 hours.

Preparation of Cr-Doped YAlO3 Red Ceramic Pigment and the Coloration Mechanism

The red ceramic pigment is widely used in industrial production, but the pigments with pure color and bright red performance are rare. Therefore, it is important to study and develop new red ceramic pigment with perfect color performance. This paper reports the preparation of Cr-doped YAlO_3 red ceramic pigment rendering by sol-gel method with high temperature resistance, good color and proposed color mechanism. The prepared samples were characterized by XRD, SEM, EDS and UV-vis, and the effects of Cr on the crystal structure, color rendering properties and color mechanism were discussed. The results showed that the optimum concentration of coloring agent（Cr） in Cr：YAlO_3 red ceramic pigment was 3 at.%. The main color mechanism was also discussed. Compared with the solid phase sintering and precipitation methods for the synthesis of red ceramic pigment, the sol-gel method possessed obvious advantages, such as perfect mixing of the raw materials, uniform dispersion of doping ions and the pure color.

高效BiOBr/红磷异质结光催化剂用于Cr(Ⅵ)光还原

将水热处理后的红磷(HRP)与溴氧化铋(BiOBr)相结合,构建BiOBr/HRP异质结复合材料。通过调节和优化组成比例,7%BiOBr/HRP复合材料(复合材料中BiOBr的质量分数为7%)表现出最高的光催化活性,其可见光还原Cr(Ⅵ)的速率常数为0.188 min^(-1),是纯HRP(0.0376 min^(-1))的5倍。在窄带隙HRP中引入宽带隙BiOBr所构建的异质结复合材料,扩大了可见光光谱吸收范围,增强了光的吸收,加速了光生电子和空穴的分离。

Disposal of wastewater containing Congo Red by synthesizing layer double hydroxide in-situ

Based on the principle of synthesis, a new method was put forward to dispose Congo Red anion-containing dyestuff from wastewater and its feasibility was also examined. The principle of the method is described as follows: Mg2+ and Al3+ are hydrolyzed to form Mg/Al-LDH by adding Mg2+, Al3+ and NaOH in wastewater containing anion dyestuff, which is selectively intercalated with the interlayer of LDH in order to balance positive structural charge. While Mg2+ and Al3+ are co-precipitated to form LDH, the anion dyestuff in wastewater will be removed by LDH synthesized in-situ, as is confirmed by X-ray diffraction analysis of settlings and chemical analysis of aqueous samples. In this work, we studied the influence of Mg/Al mole ratio, pH value, time and temperature of reaction on the removal of anion dyestuff and the use of Mg and Al. The experimental results showed the maximum removal efficiency of anion dyestuff could be attained when pH value was 9.0, and Mg/Al mol ratio was 2∶1, reaction duration was 2 hours, and the effect of temperature was not remarkable, and the removal efficiency could reach 100%. Meanwhile, the Mg and Al added could be made good use of. This technology has the advantage of extraordinary efficiency of wastewater disposal.