Treatment Of Methylene Blue Dye Research Articles

Treatment of Methylene Blue Dye using Natural Adsorbents

Treatment of Methylene Blue Dye using Natural Adsorbents

Novel evolution of gamma irradiated PVP/Cu–Ag nanocomposite for dye polluted water treatment

A novel polyvinylpyrrolidone/copper–silver (PVP/Cu–Ag) nanocomposite was synthesized via aqueous solution reduction and gamma radiation techniques for the treatment of methylene blue dye (MB) polluted water as a common organic dye pollutant in wastewater which is harmful to human health and aquatic life. Different analyses were used for the characterization of the synthesized Cu–Ag nanoparticles (NPs) and PVP/Cu–Ag nanocomposites such as XRD, TEM, DLS, FTIR, EDX, and TGA The XRD results indicated the typical peaks of CuNPs and AgNPs and the formation of pure crystalline nanoparticles in addition to their corresponding peaks were noticed in the PVP/Cu–Ag nanocomposite. Results of FTIR for the PVP/Cu–Ag nanocomposite confirmed the successful interaction between Cu–Ag NPs and PVP chains. The SEM of the PVP/Cu–Ag nanocomposite appeared rough and dense porous surface with white spots of Cu–Ag nanoparticles that dispersed homogeneously all over the surface of the PVP matrix. The effect of the dose of gamma radiation on the gelation and swelling of PVP hydrogel and PVP/Cu–Ag nanocomposite was studied. Using 15 kGy, the gel content of 89% and 97.1% for PVP and PVP/Cu–Ag, respectively. The swelling degree of PVP/Cu–Ag nanocomposite shows pH dependence and the maximum swelling was at pH 6. The point of zero charge (pHpzc) of PVP/Cu–Ag nanocomposite was 5.8. The factors affecting the removal of MB dye were evaluated as the effect of reaction time, dosage, temperature, pH, and dye concentration. The PVP/Cu–Ag nanocomposite shows fast adsorption of MB dye with a removal percentage of 95% after 50 min, at pH 8, 200 mg/L dye concentration, and 0.1 g nanocomposite dosage. Based on the kinetic, isotherm, and thermodynamic studies, it was found that the adsorption of MB dye onto PVP/Cu–Ag nanocomposite fitted to the Pseudo-second-order kinetic model and the Langmuir isotherm model and the reaction was an endothermic, spontaneous, and chemisorption. The fast removal of the dye using the PVP/Cu–Ag nanocomposite confirms its possible use in wastewater treatment applications as an effective adsorbent for dye treatment.

Treatment of Methylene Blue Using Ni-Al/Magnetite Biochar Layered Double Hydroxides Composite by Adsorption

Methylene blue dye is hard to degrade and requires treatment using Ni-Al Layered double hydroxides (LDHs) modified with magnetite biochar (MBC) to form Ni-Al/magnetite biochar composite in overcoming environmental pollution. Material attainment was identified by characterization using X-Ray Diffraction (XRD), Fourier Transform – Infra Red (FT-IR), Branuer Emmet Teller (BET), Scanning Electron Microscopy – Energy Dispersive X-Ray (SEM-EDX) and Vibration Sample Magnetometer (VSM). XRD characterization displays angle 2θ at 11°, 60° is a typical angle of LDH, and angles 22° and 35° of magnetite biochar. FT-IR characterization analysis at wavelength 1381 cm-1 for NO3- group and M-O group at wave number 700 cm-1. C-H group on biochar at 1404 cm-1 and wave number 586 cm-1 for Fe-O group. BET characterization analysis of Ni-Al/MBC has a large surface area and pore volume of 127.310 m²/g and 0.1950 cm³/g. SEM characterization analysis of Ni-Al/MBC has large, coarse pores and non-uniform shape, EDX data shows that there are forming elements such as Ni, Al from LDH and, Fe, C elements from magnetite biochar. pH, kinetics, isotherms, and thermodynamics become influential in adsorption processes. The adsorption capacity of the composite reaches 68.493 mg/g by following the Langmuir equation and adsorption kinetics refers to the Pseudo Second Order (PSO) equation. Adsorption continuity is spontaneous and endothermic. Ni-Al/MBC has stability in the process of adsorbent regeneration up to five adsorption cycles and, therefore can be used as a potential adsorbent in the treatment of methylene blue dye in aqueous environmental pollution. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

3D‐Printed TiO2 Electrode as a Viable Alternative for Photoelectrocatalytic Purification of Water

AbstractA commercial pure titanium (cp‐Ti) powder was used to produce a photoelectrode substrate via 3D‐printing and a commercial titanium foil (Ti‐foil) was used as substrate for direct comparison. TiO2 nanotubes were prepared on both Ti substrates via electrochemical anodization. Characterisation of electrodes showed similar results in all aspects analysed: morphology, absorbance, crystallinity, and photo‐current response. The efficiency of photoelectrocatlytic treatment of methylene blue dye (MB) in water with a single‐chip UVA‐LED was identical. The cp‐Ti/TiO2 electrode achieved 93±4 % removal of MB after 210 min, when combined with a four‐chip UVA‐LED. The cp‐Ti photoelectrode was also tested for the first time for photoelectrocatalytic treatment of benzothiazole (BTH). The highest degradation of BTH (98±2 %, 120 min) was also achieved using the four‐chip UVA‐LED. This study supports further development of 3D‐printed electrodes, maximizing the potential for the creation of novel electrodes for use in PEC technologies for abatement of organic pollutants.

Green synthesis of graphene-oxide based nanocomposites for efficient removal of methylene blue dye from wastewater

Water-soluble dyes are a common problem in wastewater treatment, requiring highly efficient methods for removal. In this study, novel sustainable adsorbents made from graphene-oxide (GO) and other materials, such as eggshell-derived calcium oxide nanoparticles (CaONPs-ES), fish bone calcium oxide nanoparticles (CaONPs-FB), and durian shell activated carbon (DSAC) were synthesized, characterized, and demonstrated for soluble dye removal from wastewater. Fermented maize grain extract (MES) was used as a green cross-linker in the synthesis process. The resulting nanocomposites, GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC, showed promising adsorption capabilities for methylene blue (MB) dye removal from aqueous environments. The prepared nanocomposites (GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC) were characterize using state-of-art instrumental techniques. The BET measurement revealed that the nanocomposites surface areas were enhanced due to the cross-linking phenomenon, improving their adsorption capability towards MB dye treatment. The adsorption data of GO@CaONPs-FB/DSAC and GO@CaONPs-ES/DSAC was well fitted to the Harkins-Jura and Freundlich models, respectively. The maximum sorption capacities of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were 1274.5 and 689.7 mg/g, respectively. The MB dye removal mechanism was driven by π-π interaction, hydrogen bonding, electrostatic attraction and physical interactions and the adsorption process of the nanocomposites followed pseudo-second-order kinetics. The adsorptive performance of the nanocomposites was stable, showing ∼96.45 % and ∼85.18 % after 10 successive cycles for GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC respectively. Cost evaluation revealed that bulk synthesis of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC nanocomposites is cost-effective for treating large quantities of MB contaminated water and other potential dyes as well. Finally, the independent and synergetic contributions between pH, adsorbent dosage and temperature on MB removal by GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were studied and optimized by central composite design (CCD) an aspect of the response surface methodology (RSM). Finally, this study suggests that the novel green cross-linking approach has a significant impact in enhancing the adsorptive performances of the developed nanocomposites to effectively capture MB from aqueous environment.

Magnetic nanocomposites prepared from red mud and durian husk as an effective bio-adsorbent for methylene blue adsorption

Abstract An increasing interest in nanocomposites prepared from agricultural/industrial byproducts has been paid for environmental remediation, especially in water treatment. This study reports the facile preparation of a low-cost magnetic biocomposite of magnetic Fe3O4 nanoparticles (NPs) incorporated with biopolymers extracted from durian husk, called bp-Fe3O4 and examined in the removal of methylene blue (MB) dye. Here, Fe2O3 NPs were first recovered from red mud waste and then converted to magnetic nanostructured Fe3O4 using a one-pot process via carbon combustion. The bp-Fe3O4 inherited the characteristics of each constituent component, while showing slightly higher saturation magnetization than the bare Fe3O4 NPs (19.84 and 18.66 emu/g, respectively), allowing for easy separation from the aqueous solution using a suitable magnet. The MB adsorption on bp-Fe3O4 reached an equilibrium state within 60 min reaction and achieved >90% of removal (at 50 mg/L MB) at an optimal pH range of 6–8. The effective adsorption of MB dye was attributed to both the hydroxylated-Fe3O4 NPs and biopolymers. The material showed excellent reusability tested up to the seventh MB adsorption cycle (decreased by <2% of adsorption efficiency). Overall, the outstanding magnetic properties and low-cost bp-Fe3O4 rendered them easily manipulated and separated, and reusable for water/wastewater treatment of MB dye.

Dacryodes edulis leaf derived biochar for methylene blue biosorption

Carbonized Dacryodes edulis leaf (CDEL) which was obtained at 250 °C, was used for the biosorption of methylene blue (MB) dye from aqueous solutions. The biosorbent was characterised using Boehm titration, pH of zero point charge (pHzpc), FTIR, SEM, XRD and ED-XRF. Mineral compositions of CDEL revealed good amounts of Fe, Ca and K which are of nutritional importance. The pH at zero point of charge (pHzpc) and specific surface area (SSA) of CDEL were found to be 7.5 and 0.983 m2/g respectively. Freundlich isotherm gave good fit to equilibrium biosorption data. Elovich kinetic model gave the best fit to kinetic data which is consistent with chemisorption. Scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) revealed effective biosorption processes. Calculated thermodynamic parameters revealed spontaneous and exothermic biosorption of MB onto CDEL. Highest amount of MB was removed at pH 4 and the percentage removal was about 93%; hence, CDEL is a good biosorbent for MB from aqueous solutions. Generally, CDEL exhibited > 70% MB removal after three adsorption-desorption cycles, showing that it is re-usable and a promising biosorbent for the treatment of MB dye contaminated water.

Synthesis, characterizations, and RSM analysis of Citrus macroptera peel derived biochar for textile dye treatment

Textile wastewater discharging to the surface water body is a great concern because it contains different pollutants such as dyes, organics, surfactants, inorganic salt and heavy metals. An effective low-cost treatment technology has not been developed yet. The objective of this study was to develop a low-cost biochar adsorbent from was from a novel Citrus macroptera peels (CMPs) using a conventional slow pyrolysis process and applied it for the treatment of methylene blue dye in an aqueous solution. The chemical functionalities, surface textures, and crystallinity of the synthesized biochar were characterized by Fourier Transform-Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscope (FESEM) analysis, and X-ray powder Diffraction (XRD), respectively. Different functional groups such as -COOH, OH, and R-OH, randomized porous structures with tunnel-like cracks were confirmed from the FTIR and FESEM, respectively. Typical non-linear disordered 3D carbon structure was predicted from the XRD. Response surface methodology (RSM) was performed with the central composite design (CCD) technique, and analytical tuning of the process variables, e.g., pH, contact time, and methylene blue concentration, was also carried out to validate the RSM optimization. The adsorption isotherms and kinetics were investigated, where isotherm and kinetics followed Langmuir and pseudo 2nd order models. RSM results at pH 8 showed 85% of dye removal within 75 min of contact time. According to the Langmuir isotherm model, the maximum adsorption capacity, qm was 139.7 mg/g, which aligned with the experimental value. The present work shows that the low-cost CMPs-derived biochar has the potential for dye removal from industrial effluents.

Photocatalytic Treatment of MB Dye Using ZnO Nanoparticles

The present study revealed the synthesis of zinc oxide nanoparticles by wet chemical co-precipitation process and were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), UV-Vis spectroscopy, and photocatalysis for Methylene Blue (MB) dye degradation. The crystallite size of the ZnO nanoparticles calculated from XRD using Debye Scherrer Formula is 36.27 nm. The size variation of the ZnO nanoparticles is due to the difference in annealing temperature and precursors. The FTIR spectra confirms the formation of ZnO nanoparticle. From UV-Vis spectra of ZnO nanoparticles, the absorption peak is at 380 nm and decreases with time which shows the dye degradation. MB dye degradation efficiency by ZnO nanoparticle is 91.78% in 21 minutes.

Biosynthesis of Silver Nanoparticles Using Orange Peel Extract for Application in Catalytic Degradation of Methylene Blue Dye

Interest in the biosynthesis of silver nanoparticles (AgNPs) has been steadily increasing primarily due to their numerous applications in various fields, low-cost, use of non-toxic environmentally-friendly materials and easy implementation. This study focused on the biosynthesis of AgNPs using orange peel extract (OPE), optimization of process conditions, and application in catalytic degradation of methylene blue (MB) dye used in the textile industry. A central composite design in response surface methodology resulted in optimum conditions of 0.0075 g dry peel/mL for OPE concentration, pH of 11 and 1.5 mM silver nitrate concentration. The optimum conditions for the response variables corresponded to the peak absorbance of 0.79 and SPR wavelength of 403.8 nm in UV-vis spectra, and minimum particle size of 12.9 nm. In addition, peak absorbance and SPR wavelength appeared to be related to the size of the AgNPs. A full-factorial design for the catalytic degradation of MB dye by the biosynthesized AgNPs for 1 h indicated the maximum influence of AgNPs compared to the concentrations of MB dye and NaBH4 in decreasing order. The MB dye was reduced rapidly with NaBH4 in the presence of AgNPs due to their catalytic action. The findings of the study show the potential of OPE for the biosynthesis of AgNPs with excellent catalytic activity for the treatment of MB dye in industrial effluent.

Dynamic Sorption of Methylene Blue (MB) Dye in Continuous Column Using Bio-Sorbent (Ailanthus excelsa Roxb)

Industrial waste containing dye poses a threat to the ecosystem and human as well as aquatic life. Methylene blue (MB, a cationic dye) has been used in excess amounts in textile, pulp and paper, rubber, plastics, cosmetics, pharmaceutical, and food industries. MB dye released in water sources makes the water toxic in nature. So, to remove the dye from wastewater various methods (physical, chemical and biological) are adopted for treatment purposes. Among them, adsorption is found to be more economical and eco-friendlier in comparison to others. Various adsorbents reported have been the literature for the removal of MB dye such as wheat straw, rice husk, cashew nut shell, sawdust, wood, pine needles, green grass, eucalyptus bark, peanut shell, coconut shell, coir dust, etc. In this experimental study, Ailanthus excelsa Roxb. (AER) is utilised for the treatment of MB dye from the wastewater in continuous mode by varying the different parameters viz., bed height, flow rate, and the initial concentration of MB dye. Yoon-Nelson and Clark’s models have been applied to predict the break through curve and to find out the characteristic parameters of column suitable for process design. The study reported that Clark’s model was found to be fit for the breakthrough curve. The findings revealed that Ailanthus excelsa Roxb. has a high adsorption potential, and it could be used to treat dye-containing effluents.

Methylene Blue Dye Adsorption from Wastewater Using Hydroxyapatite/Gold Nanocomposite: Kinetic and Thermodynamics Studies.

The present work demonstrates the development of hydroxyapatite (HA)/gold (Au) nanocomposites to increase the adsorption of methylene blue (MB) dye from the wastewater. HA nanopowder was prepared via a wet chemical precipitation method by means of Ca(OH)2 and H3PO4 as starting materials. The biosynthesis of gold nanoparticles (AuNPs) has been reported for the first time by using the plant extract of Acrocarpus fraxinifolius. Finally, the as-prepared HA nanopowder was mixed with an optimized AuNPs solution to produce HA/Au nanocomposite. The prepared HA/Au nanocomposite was studied by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) analysis. Adsorption studies were executed by batch experiments on the synthesized composite. The effect of the amount of adsorbent, pH, dye concentration and temperature was studied. Pseudo-first-order and pseudo-second-order models were used to fit the kinetic data and the kinetic modeling results reflected that the experimental data is perfectly matched with the pseudo-first-order kinetic model. The dye adsorbed waste materials have also been investigated against Pseudomonas aeruginosa, Micrococcus luteus, and Staphylococcus aureus bacteria by the agar well diffusion method. The inhibition zones of dye adsorbed samples are more or less the same as compared to as-prepared samples. The results so obtained indicates the suitability of the synthesized sample to be exploited as an adsorbent for effective treatment of MB dye from wastewater and dye adsorbed waste as an effective antibacterial agent from an economic point of view.

Microwave treated Bermuda grass as a novel photocatalyst for the treatment of methylene blue dye from wastewater

Microwave treated Bermuda grass (MW-BG) has been developed and tested for the removal of a toxic cationic dye, methylene blue (MB). The dye removal has been investigated for both adsorption and photocatalytic degradation. The microscopic characterizations reveal that MW-BG’s flat morphology with a smooth surface aids the uptake of the dye contaminant, in spite of the key role played by the presence of functional groups was key in deciding better adsorption performance. The maximum adsorption capacity of MWBG sample has been shown to be 171.25 mgg−1. The adsorbent performs well in the dye concentration range of 25−40 mg L−1 and the adsorption data shows an excellent correlation with both Langmuir and Freundlich isotherms while obeying pseudo-second-order kinetics. The material also efficiently degraded MB up to 96.7 % in 180 min when initial MB concentration was 10 mg L−1. In summary, MWBG is potential as a material for remediation of water containing toxic dye because of its abundance and no additional requirements of pre-treatment or carbonization. Such materials act as a suitable reference for researchers trying to develop better and alternate photocatalysts for the treatment of wastewaters

Adsorption of methylene blue onto betel nut husk-based activated carbon prepared by sodium hydroxide activation process.

In this study, activated carbon (AC) was prepared from agro-waste betel nut husks (BNH) through the chemical activation method. Different characterization techniques described the physicochemical nature of betel nut husks activated carbon (BNH-AC) through Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and pH point of zero charge. Later, the produced AC was used for methylene blue (MB) adsorption via numerous batch experimental parameters: initial concentrations of MB dye (25-250 mg/L), contact time (0.5-24 hours) and initial pH (2-12). Dye adsorption isotherms were also assessed at three temperatures where the maximum adsorption capacity (381.6 mg/g) was found at 30 °C. The adsorption equilibrium data were best suited to the non-linear form of the Freundlich isotherm model. Additionally, non-linear pseudo-second-order kinetic model was better fitted with the experimental value as well. Steady motion of solute particles from the boundary layer to the BNH-AC's surface was the possible reaction dynamics concerning MB adsorption. Thermodynamic study revealed that the adsorption process was spontaneous and exothermic in nature. Saline water emerged as an efficient eluent for the desorption of adsorbed dye on AC. Therefore, the BNH-AC is a very promising and cost-effective adsorbent for MB dye treatment and has high adsorption capacity.

Treatment of Methylene Blue Dye Using Immersed Lamp Photocatalytic Reactor: 5 L Scale Study

The present investigation studied methylene blue dye treatment using 5-L immersed lamp photocatalytic (UV) reactor. Dye treatment further studied using catalysts effects such as H2O2, ZnO, and TiO2. The marginal higher degradation was obtained for ZnO/UV compared to TiO2/UV effect, and it may be due to higher bandgap energy of ZnO. The maximum degradation was obtained for H2O2/UV (2 g/L) effect. The optimum findings of the present work were initial dye concentration: 31.3 µM, pH: 11, operating temperature: 28 °C, moles of dye removed: 30.1 ± 1.6 µM, moles of total organic carbon removed: 350.4 ± 17.5 µM, rate constant (pseudo-first order): 18.3 ± 0.7 × 10−3 min−1, and energy: 9.4 ± 0.4 × 10−3 µM. The present work showed the higher potential of scale-up photocatalytic reactor for treatment dye pollutants.

Preparation, magnetic properties, and photocatalytic performance under natural daylight irradiation of Fe3O4-ZnO core/shell nanoparticles designed on reduced GO platelet

Ternary mesoporous nanocomposites of RGO/Fe3O4-ZnO were prepared successfully via hydrothermal technique. Fe3O4-ZnO core/shell nanoparticles were decorated on the surface of reduced graphene oxide platelet to improve charge separation efficiency and magnetic properties. The phase, microstructure and specific surface area of the prepared samples were determined via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy/selected area electron diffraction (TEM/SAED) and Brunauer–Emmett–Teller (BET) techniques. A vibrating sample magnetometer (VSM) was used for recording the magnetization hysteresis curves. The methylene blue (MB) degradation and photocatalytic activities of prepared catalysts were examined under natural daylight irradiation. The magnetic properties of the RFZ photocatalyst increased compared with the FZ from 12.45emug−1 to 20.18emug−1. The specific surface area (as,BET) for the RFZ compared to the FZ increased from 31.56m2g−1 to 36.05m2g−1. The RFZ photocatalyst, as a result of synergistic effects, indicated an excellent performance for treatment of MB dye. The photocatalytic reactions obeyed pseudo-first-order kinetics and apparent rate constant (kap) of RFZ photocatalyst increased compared to FZ. Furthermore, the RFZ photocatalyst could be recycling using a common magnet besides to the high efficiency of degradation. The repeatability of the photocatalytic activity after 10 cycles was additionally tested and revealed that the RFZ photocatalyst up to 8 cycles showed a small drop in catalysis efficiency. Thus, it was concluded that the RFZ ternary photocatalyst can be an economical multifunctional photocatalyst for the degradation of unsafe compounds in wastewater.

Assessment of hydrothermally modified fly ash for the treatment of methylene blue dye in the textile industry wastewater

Dyes and pigments are one of the major water pollutants and if not discharged properly cause ecological disturbance. Considering this, the current study investigates the application of thermal power plant by-product, i.e., fly ash for the elimination of a hazardous methylene blue dye from its synthetic aqueous solution. Experiments were conducted in batch mode to study the effect of pH, temperature, adsorbent dose and contact time. Highest dye removal (94.3%) was achieved at pH 10 using adsorbent dose of 10 g/L in 90 min of contact time at 40 °C. However, for cost-effective operation at neutral pH and room temperature (30 °C), it yields 89.3% dye removal having similar dose and contact time. Equilibrium isotherms for adsorption were analyzed by Langmuir and Freundlich, Temkin and Dubinin–Radushkevich isotherm equations. The results revealed that the best fit model of adsorption closely followed Langmuir adsorption. Based on adsorption isotherm models, thermodynamics parameters ΔG, ΔH and ΔS were calculated. The negative value of ΔG and ΔH revealed that adsorption process was exothermic, spontaneous and physical. The present work suggests that through simple process hydrothermally modified fly ash has the potential to be used as cost-effective and efficient adsorbent for the treatment of wastewater from textile industries.

Removal of Methylene Blue Dye Pollutant from Aqueous Solution Using Sugar Cane Bark and Chaff Biomass

The removal of Methylene blue (MB) dye pollutant from aqueous solution using sugar cane bark (SCB) and chaff (SCC) was studied using batch experiments. The operating variables studied were initial biomass dose, initial dye concentration, contact time, pH and temperature. The result revealed that the amount of MB dye uptake, qe (mg/g) increased with an increase in temperature, dye concentration and contact time, but decreased with an increase in adsorbent dosage. Equilibrium data were found to obey Langmuir isotherm for both biomass, showing a monolayer adsorption mechanism. The monolayer sorption capacity of SCB and SCC for MB dye were found to be 1.282mg/g and 1.706mg/g, respectively at 303K. The thermodynamics parameters of the MB / biomass system indicate spontaneous (ΔG◦ <0) and endothermic (ΔH > 0) process. The study show that SCB and SCC which are common environmental wastes can be used for the treatment of MB dye polluted water.

Removal of Methylene Blue Dye Pollutant from Aqueous Solution Using Sugar Cane Bark and Chaff Biomass

The removal of Methylene blue (MB) dye pollutant from aqueous solution using sugar cane bark (SCB) and chaff (SCC) was studied using batch experiments. The operating variables studied were initial biomass dose, initial dye concentration, contact time, pH and temperature. The result revealed that the amount of MB dye uptake, qe(mg/g) increased with an increase in temperature, dye concentration and contact time, but decreased with an increase in adsorbent dosage. Equilibrium data were found to obey Langmuir isotherm for both biomass, showing a monolayer adsorption mechanism. The monolayer sorption capacity of SCB and SCC for MB dye were found to be 1.282mg/g and 1.706mg/g, respectively at 303K. The thermodynamics parameters of the MB / biomass system indicate spontaneous (ΔG◦<0) and endothermic (ΔH >0) process. The study show that SCB and SCC which are common environmental wastes can be used for the treatment of MB dye polluted water.

Visible light-activated cadmium-doped ZnO nanostructured photocatalyst for the treatment of methylene blue dye

An attempt was made to prepare Cd-doped ZnO photocatalyst for visible light assisted degradation of a textile dye (methylene blue, MB) in aqueous solutions by a traditional sol–gel process. The as-prepared nanoparticles were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, and photoluminescence spectra techniques. The results showed that the Cd-doped ZnO possess the single-phase hexagonal wurtzite structure. The photocatalytic activity of the nanoparticles under visible light was investigated by measuring the photodegradation of MB in aqueous dispersion. The effects of key operation parameters such as initial dye concentration, catalyst loading as well as initial pH value on the decolorization extents were investigated. The results indicate that the decolorization of the organic molecule followed a pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. Under the optimum operation conditions, approximately 85.0% dye removal was achieved within 3.5 h.