Poly[hydroxybutyrate-co-hydroxyvalerate] and cellulose biocomposite membrane derived from sugarcane bagasse for Congo red dye and vegetable oil removal in water remediation

ABSTRACTCornulaca monacantha stem (CS) and biomass stem-based activated carbon (CSAC) were explored for the removal of congo red (CR) dye from water system. The biomaterial was characterized using Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and field emission scanning electron microscope (FESEM). The BET surface area of biomass stem-based activated carbon (CSAC) was recorded to be 304.27 m2/g. The influence of different parameters such as initial CR concentration, adsorbent dosage, contact time, adsorbate pH and temperature onto CR adsorption were studied.The maximum adsorption of CR dye 97.19% and 86.43% were achieved at 55°C using CSAC and CS adsorbents, respectively. The isotherm, kinetics and thermodynamic study were also investigated to explore the adsorption mechanism. The adsorption isotherm closely follow the Langmuir model (R2 = 0.99) suggesting the monolayer adsorption of CR dye. Kinetic results indicated that pseudo second-order and Elovich model provide the better regression coefficient. Thermodynamic study revealed the feasible, spontaneous and endothermic nature of adsorption process. The regeneration study implies that adsorbent was efficiently recovered from CR dye with 0.01 mol/L NaOH solution. The CSAC adsorbent possesses 75.75% uptake for CR dyes after 6th cycles of desorption-adsorption, respectively. .

Environmental applications of flame synthesized CuO nanoparticles through removal of Congo Red dye

The discharge of industrial effluents containing harmful synthetic dyes has gone up significantly since the last few decades and poses a severe environmental threat. Among a wide variety of treatment techniques available for the remediation of dye-laden wastewater, the adsorption process has been reported to be an effective method. Nanoscale adsorbents derived from metal oxides and their composites have recently attracted attention due to their enhanced ability to adsorb contaminants. The removal of congo red (CR) dye from dye solution was studied using a new adsorbent Fe–Mn-Zr trimetal oxide nanocomposite synthesized with polyaniline (PANI). The structural characterization of the Fe–Mn-Zr/PANI was investigated by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) analysis and energy dispersive X-ray (EDX) analysis. It was observed that the adsorption process was substantially dependent on sonication time, the dose of adsorbent and the initial concentration of CR dye. Optimum solution pH was obtained as 5.0 from the effect of the pH study that has been performed for different initial concentrations of CR dye. The maximum percentage of adsorption efficiency for CR dye obtained was 89.25% at the initial concentration of 20 mg/L, with 0.2 g/L adsorbent dose and pH 5.0 within 15 min. In this work, kinetic analysis was performed utilizing pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models, with the second-order kinetics model being shown to be the best fit. In comparison to pseudo-first-order kinetics, the experimental and calculated values of Qe for the pseudo-second-order kinetics were in good agreement. The isotherm study was performed by varying the initial CR concentration from 5 to 70 mg/L with 0.1–0.4 g/L adsorbent dose. The adsorption experiments are best fitted with the Langmuir isotherm, giving a CR dye adsorption capacity of 111.111 mg/g at pH 5.0. The correlation coefficient value (0.991) indicates an accurate fit for the Langmuir model. The primary adsorption mechanism is the electrostatic interaction between the sulfonated group (–SO3Na) of negatively charged CR dye molecules and the positively charged amine group (–NH2) of PANI surface. The response surface methodology (RSM) was studied to optimize the removal of the CR dye used with different experimental parameters like initial CR concentrations (5, 10, 15, 20 and 25 mg/L), with adsorbent dose (0.1–0.5 g/L), at reaction time (2 min, 4 min, 6 min, 8 min and 10 min) and solution pH: 5.0. Maximum CR dye removal of 97.78% was obtained at an optimum contact time of 15 min, with an initial CR dye concentration of 20 mg/L and adsorbent dose at 0.2 g/L.KeywordsMetal oxide nanoparticlesPolyanilineNanocompositeCongo redDye adsorptionResponse surface methodologyAdsorption mechanismKinetic studyIsotherm modellingCentral composite designOptimization

Wastewater treatment is of utmost importance in providing all equitable and safe drinking water. In the present study, a chitosan impregnated sugarcane bagasse biochar SCNC biocomposite has been synthesized for the removal of Congo red (CR) dye from an aqueous solution. The SCNC biocomposite was thoroughly characterized through Brunauer, Emmett and Teller (BET) and N2 adsorption isotherm, point of zero charge (pHPZC), elemental analysis, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA) analysis. Moreover, SCNC biocomposite was further employed to remove CR dye from the aqueous solution in batch mode. The SCNC biocomposite could remove more than 95.0% of CR at an initial concentration of (100mgL− 1), adsorbent dosage (0.05 g), time (200 min), pH ~ 3. The SCNC biocomposite achieved maximum adsorption capacity of 170mgg− 1. The equilibrium adsorption data for CR dye were best fitted to the Langmuir isotherm model with R2, 0.999. The kinetic and isotherm were statistically investigated using the chi-square statistic (χ2 ), mean square error (MSE), and the sum of squares error (SSE) Because of the higher correlation coefficient (R2 ≥ 0.999) and lower error functions, the equilibrium CR adsorption isotherms for a single-dye system fit Langmuir and the PSO kinetic model. The thermodynamic studies revealed the spontaneous and endothermic nature of adsorption of CR dye onto SCNC biocomposite. The SCNC biocomposite can be regenerated up to the 5th cycle successfully. The mechanism of CR adsorption onto SCNC was elucidated.

Mechanistic aspects for the removal of Congo red dye from aqueous media through adsorption over N-doped graphene oxide nanoadsorbents prepared from graphite flakes and powders

This study describes the ability of green kyllinga weed extract (GKWE) with silver nanoparticles (AgNPs) as catalysts for the removal of congo red (CR) dye from synthetic coloring wastewater. AgNPs were synthesized using GKWE as a reducing agent, resulting in the formation of AgNPs with an average size of 17.64 nm. For the catalytic study, the experiment was carried out in batch mode. Different parameters such as the effect of pH, amount of AgNPs as a catalyst, initial CR dye concentration, and amount of GKWE were evaluated for the removal of CR dye for 30 mins reaction times. The CR removal was achieved between 91.2% and 96.7% at the optimum condition which is at pH 2, 0.5 mL of 2 mM AgNPs as a catalyst, 60-100 mg/L of initial CR dye concentration, and 1 mL amount of GKWE were used. The result showed that the combination between GKWE and AgNPs had a synergy interaction in enhancing the removal of CR dye from coloring wastewater via the coagulation-flocculation and sedimentation process.

Removal of Congo red dye from aqueous solution with hydroxyapatite/chitosan composite

Polymer–agro-waste composites for removal of Congo red dye from wastewater: adsorption isotherms and kinetics

Graphene oxide–MnFe2O4 nanohybrid material as an adsorbent of Congo red dye

Calcined biomass-bentonite composites as eco-friendly adsorbents for the treatment of toxic anionic and cationic dye wastewater

Folic acid modified cross-linked cationic polymer: Synthesis, characterization and application of the removal of Congo red dye from aqueous medium

Adsorptive removal of congo red dye from aqueous solution using bael shell carbon

Nowadays, aquatic pollution is one of the most important global challenges, due to discharges a wide variety of various hazardous materials from different activities which have significant environmental, economic and healthy impacts. Industries and activities related to organic dyes onsume large amounts of water and contribute significantly to the growing problem of water pollution. The current study describes the conversion of plant wastes into activated carbon sphere incorporated sulfonated polystyrene (AC/SPS) for adsorptive removal of Rhodamine B (RhB) and Congo Red (CR) dyes in a batch process. The prepared materials were characterized by different techniques such as XRD, FTIR, FESEM, TEM, BET-BJH, and TGA. The AC/SPS in weight ratio of 10% was used as a novel adsorbent for RhB and CR remediation. Batch adsorption experiment have been studied by investigating the effect of contact time, adsorbent dose, initial pH, and temperature. The maximum removal efficiency of RhB and CR onto AC/SPS under optimized conditions was estimated to be 34% and 98%, respectively. In addition, it has been found that Freundlich model provided the most appropriate fit for the adsorption of both RhB and CR dyes. Based on the thermodynamic study, it was proven that the adsorption process for both dyes is endothermic and spontaneous. The change in entropy was estimated to be 190.59 and 65.40 J/mol K for CR and RhB dyes, respectively. The kinetic study revealed that the adsorption of CR and RhB dyes followed the pseudo-second order and pseudo-first order kinetic models, respectively.Graphical Abstract

Adsorption dynamics of Congo red dye removal using ZnO functionalized high silica zeolitic particles

In this study, the adsorption characteristics of crystal violet (CV) and Congo red (CR) dyes from the aqueous solution onto prepared activated carbon were examined. The activated carbon was prepared from wood apple shell by chemical activation with ZnCl2. The parameters studied were the effect of contact time, initial dyes concentration, and pH of solution. The experimental equilibrium data were analyzed and fitted to Langmuir, Freundlich, and Temkin isotherms. The maximum monolayer adsorption capacities of CV and CR dyes were found to be 142.85 and 83.33 mg per gram of prepared activated carbon at 298 K. The kinetic data obtained at different concentrations were analyzed using pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. Batch adsorption kinetic studies showed that the adsorption of dyes followed pseudo-second-order kinetics and at four different concentrations of both dyes, indicating that chemisorption is the rate-limiting step. Thermodynamic studies reveal that the removal of dyes from aqueous solution onto activated carbon was a spontaneous, feasible, and endothermic process at a temperature greater than standard equilibrium temperature.