Sustainable synthesis of CQD-modified ZIF-8 from sago hampas for improved methylene blue dye removal

Organic dyes, present in the aquatic environment, have negative effects on ecosystems. Attempts are being made to remove these dyes by using number of physico-chemical methods. Out of all the methods, adsorption technique is the most economical and efficient technique. However, for this purpose, efficient and cost-effective adsorbents are needed. In this paper processed neem leaf powder (NLP) has been used for methylene blue (MB) dye removal. NLP has been characterized by X-ray diffraction, FTIR spectroscopic, and scanning electron microscopic techniques. Results have shown that NLP has crystalline character with number of functional groups. MB is removed by using NLP under different varying conditions such as NLP doses, varying MB concentration, and different pH. When fixed amount of NLP (0.2 g) is used, removal of MB increases with time and becomes almost constant after 40 min. Maximum MB removal is obtained at pH = 6.0. Adsorption isotherms and kinetic models are discussed and the data fitted well with Langmuir isotherm and pseudo second order kinetic models. Ab initio calculations have shown that nature of interaction depends on the orientation of groups and both type of adsorption is feasible in the present system. Results show that NLP is an effective adsorbent for removal of MB dye.

Whilst adsorption process is the preferred method of purifying wastewater due to its benefits, problems with the recovery of spent adsorbents are still prevalent in wastewater treatment technology. The use of magnetized biomass-based adsorbents (biosorbents) to ease the regeneration process would be a novel approach to overcome this obstacle. The magnetization of orange peel adsorbent involves a series of preparation stages. In this context, there are several parameters that may affect the magnetization of orange peel (OP) such as the ratio between FeCl3•6H2O and FeCl2•4H2O, mass of untreated orange peel (UOP), volume of NH3 solution, magnetization temperature and magnetization period. In this study, Fractional Factorial Design (FFD) was adopted to identify the significant parameters affecting two different responses namely the success of magnetization process and methylene blue (MB) dye removal. Based on the ANoVA results, the significant parameters affecting the success of the magnetization process were magnetization temperature, interaction between ratio of FeCl2:FeCl3 and volume of ammonia, and mass of OP with duration of mixing. Whereas the significant parameters affecting the MB dye removal were all five of the individual parameters, along with the interaction of amount of OP with the other four parameters, interaction between volume of ammonia with duration of mixing and with ratio of FeCl2:FeCl3, interaction between duration of mixing with temperature and ratio of FeCl2:FeCl3, and interaction between temperature and ratio of FeCl2:FeCl3. The highest recorded MB removal was 89.18%, while the lowest recorded MB removal was 38.76%. The regeneration study also showed that magnetized orange peel could be regenerated at least six times without having a significant reduction in adsorption capacity. The major functional groups of magnetized orange peel before adsorption, after adsorption and after regeneration were all similar, indicating that the spent adsorbent could be regenerated.

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

Mesoporous activated carbon from mangosteen (Garcinia mangostana) peels by H3PO4 assisted microwave: Optimization, characterization, and adsorption mechanism for methylene blue dye removal

Novel, facile, and fast technique for synthesis of AgCl nanorods loaded on activated carbon for removal of methylene blue dye

This paper deals with the prediction of methylene blue (MB) dye removal under the influence of titanium dioxide nanoparticles (TiO NPs) through deep neural network (DNN). In the first step, TiO NPs were prepared and their morphological properties were analysed by scanning electron microscopy. Later, the influence of as synthesized TiO NPs was tested against MB dye removal and in the final step, DNN was used for the prediction. DNN is an efficient machine learning tools and widely used model for the prediction of highly complex problems. However, it has never been used for the prediction of MB dye removal. Therefore, this paper investigates the prediction accuracy of MB dye removal under the influence of TiO NPs using DNN. Furthermore, the proposed DNN model was used to map out the complex input-output conditions for the prediction of optimal results. The amount of chemicals, i.e., amount of TiO NPs, amount of ehylene glycol and reaction time were chosen as input variables and MB dye removal percentage was evaluated as a response. DNN model provides significantly high performance accuracy for the prediction of MB dye removal and can be used as a powerful tool for the prediction of other functional properties of nanocomposites.

Potential utilization of Jatropha curcas L. press-cake residue as new precursor for activated carbon preparation: Application in methylene blue removal from aqueous solution

Optimum preparation conditions of rubberwood sawdust based activated carbon (RSAC) for methylene blue (MB) dye removal was studied. RSAC was produced by applying physiochemical activation method by using potassium hydroxide as a chemical agent which accompanied by carbon dioxide gasification under microwave heating. The effects of microwave power, irradiation time and impregnation ratio on two types of responses namely MB removal and RSAC yield using the center composite design (CCD) were also included in this study. The preparation variables correlation for responses was developed by two quadratic models. Optimum preparation conditions of RSAC were obtained at microwave power, irradiation time and IR of 354 W, 4.5 minutes and 0.98, respectively, which resulted MB removal and yield of 83.79% and 28%, respectively. The average pore diameter, surface area and total pore volume of optimized RSAC were 4.12 nm, 796.33 m2/g and 0.4219 cm3/g, respectively. This sample was found to has well-developed pores on its surface and can be a promising adsorbent for MB removal from aqueous solution.

Utilizing Glutaraldehyde crosslinked sodium carboxymethyl cellulose (CMC-GA) hydrogel and its nanographene oxide composite (CMC-GA-GOx), an effective carboxymethyl cellulose-graphene oxide biobased composites adsorbent was developed for the adsorption removal of methylene blue (MB) cationic dye contaminate from industrial wastewater. The CMC-GA-GOx composites developed were characterized using FTIR, RAMAN, TGA, SEM, and EDX analysis instruments. Through batch experiments, several variables affecting the removal of MB dye, including the biocomposites GO:CMC composition, adsorption time, pH and temperature, initial MB concentration, adsorbent dosage, and NaCl concentration, were investigated under different conditions. The maximum dye removal percentages ranged between 93 and 98%. They were obtained using biocomposites CMC-GA-GO102 with 20% GO weight percent, adsorption time 25 min, adsorption temperature 25 °C, MB concentrations 10–30 ppm, adsorption pH 7.0, and 0.2 g adsorbent dose. The experimental data of the adsorption process suit the Langmuir isotherm more closely with a maximal monolayer adsorption capacity of 76.92 mg/g. The adsorption process followed the kinetic model of pseudo-second order. The removal of MB was exothermic and spontaneous from a thermodynamic standpoint. In addition, thermodynamic results demonstrated that adsorption operates most effectively at low temperatures. Finally, the reusability of the developed CMC-GA-GO102 has been proved through 10 successive cycles where only 14% of the MB dye removal percentage was lost. These results suggest that the developed CMC-GA-GO102 composite may be an inexpensive and reusable adsorbent for removing organic cationic dyes from industrial wastewater.

A comparative study for the removal of methylene blue dye by N and S modified TiO2 adsorbents

Critical environmental issues have emerged from wastewater of industrial textile effluent discharge which consists of refractory dyes. Effective methods such as activated carbon (AC) adsorption is extremely demanded for solving this environmental pollution. In this study, low-cost AC was developed from Parkia speciosa pods (PSP) using microwave-assisted activation technique for the methylene blue (MB) dye adsorption. Optimization on activating conditions in terms of MB removal and AC yield was performed using response surface methodology (RSM). The optimum microwave irradiation power (MIP) of 416.50 W was found to have significant effect on MB removal at 2 minutes activation. The Parkia speciosa pods activated carbon (PSPAC) possessed intermediate surface area and total pore volume of 51.3 m 2/g and 0.0681 cm 3/g, respectively. PSPAC surface morphology was microscopically observed with highly porous structure indicating characteristics of good AC. Batch adsorption studies with various initial concentrations discovered that MB adsorption increased with increasing initial concentrations and contact time. The experimental data was in close fit using Langmuir isotherm and followed pseudo-first-order kinetic models. The MB dye adsorption process was governed by simultaneous surface adsorption and intraparticle diffusion. The results of studies proved that PSPAC is a potential adsorbent for dye-contaminated wastewater.

The present study investigated iron molybdate (Fe2(MoO4)3), synthesized via a simple method, as a nanosorbent for methylene blue (MB) dye removal from aqueous solutions. Investigations of the effects of several parameters like contact time, adsorbent dose, initial dye concentration, temperature and pH were carried out. The results showed that MB removal was affected, significantly, by adsorbent dose and pH. Interestingly, lower values of adsorbent dose resulted in the removal of higher amounts of MB. At the optimum pH, the removal efficiency of 99% was gained with an initial MB concentration of ≤60 ppm. The kinetic study specified an excellent correlation of the experimental results with the pseudo-second-order kinetics model. Thermodynamic studies proved a spontaneous, favorable and endothermic removal. The maximum amount of removal capacity of MB dye was 6173 mg/g, which was determined from the Langmuir model. The removal efficiency was shown to be retained after three cycles of reuse, as proven by thermal regeneration tests. The presence and adsorption of the dye onto the Fe2(MoO4)3 nanoparticle surface, as well as the regeneration of the latter, was ascertained by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). These findings are indicative that the investigated nanosorbent is an excellent candidate for the removal of MB in wastewater.

This study demonstrates the feasibility of Algerian native pine tree bark (NPTB) as a low-cost, sustainable adsorbent for methylene blue (MB) dye removal from wastewater. Characterization revealed a porous structure with a high surface area and abundant functional groups, ideal for adsorption. Batch experiments optimized conditions for maximum MB removal (99.47%) at pH 8, 55 °C, and 0.4 g NPTB dosage. Kinetic analysis confirmed pseudo-second-order kinetics and intraparticle diffusion, indicating chemisorption. The Freundlich isotherm model best described adsorption, with a monolayer capacity of 37.15 mg/g. Thermodynamic studies indicated the process was spontaneous, endothermic, and feasible at higher temperatures. The estimated cost of NPTB is $0.1376 USD/m³, and its low overall treatment cost makes it a promising and environmentally friendly alternative for wastewater treatment.

Herein, the potential of Macadamia integrifolia nutshell powder (MSP) as a sustainable, renewable, and cost-effective biosorbent for methylene blue (MB) dye was evaluated. The physicochemical properties of MSP were characterized via XRD, FTIR, FESEM-EDX, and pHpzc analysis. The biosorption process was optimized using the Box-Behnken design (RSM-BBD), to evaluate the influence of MSP dose (0.02–0.1 g/100 mL), contact time (20–300 min), and solution pH (4–10). The desirability function further refined and validated the BBD results, demonstrating that maximum MB removal (98.7%) was achieved at an MSP dose of 0.09 g/100 mL, contact time of 276.1 min, and solution pH of 8.7. Kinetic modeling indicated that MB biosorption onto MSP conformed to the pseudo-second order (PSO) model. The intraparticle diffusion (IPD) model supports a multi-step adsorption process, consisting of surface adsorption, gradual diffusion, and equilibrium stages. The adsorption equilibrium data were well described by the Langmuir and Freundlich isotherm models, confirming a combination of monolayer and multilayer adsorption profiles. The maximum adsorption capacity (qmax ) of MSP was estimated to be 128.3 mg/g. The biosorption mechanism was attributed to hydrogen bonding, π-π interactions, electrostatic forces, and pore filling, as evidenced by spectroscopy and bioadsorbent morphology results. The reusability study demonstrated that MSP retained significant adsorption capacity over multiple cycles, highlighting its moderate recyclability. These findings establish MSP as a highly efficient, scalable, and environmentally sustainable bioadsorbent for MB dye removal, offering a practical solution for wastewater treatment applications and options for sustainable water management.

This study investigates the treatment of natural zeolite clinoptilolite (NZC) through acid and base pretreatments, aiming to enhance its adsorption efficiency for methylene blue (MB) dye removal. The results indicate that NZC treated with 3.0 M HCl (hydrochloric acid) exhibits superior MB removal efficiency (93.24 %) compared to 1.0 M NaOH (sodium hydroxide)-treated NZC (91.40 %), accompanied by a higher Brunauer–Emmett–Teller (BET) surface area (135.5002 m2/g) in contrast to (43.6059 m2/g). The optimized 3.0 M HCl-treated NZC is further functionalized with curcumin, resulting in CUR-HCl-NZC, which demonstrates enhanced MB removal efficiencies of 95.09 % at 45 min and 83.81 % at 90 min, surpassing untreated NZC. The adsorption parameters, including contact time (45 min), adsorbent dosage (0.2 g), and initial dye concentration (25 ppm), are systematically varied to optimize the conditions for CUR-HCl-NZC. Characterization through Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and BET analysis confirm the successful binding of curcumin to HCl-treated NZC, revealing structural and surface modifications. BET analysis shows that the surface area of CUR-HCl-NZC is 100.0382 m2/g, indicating changes in porosity due to curcumin modifications. The isotherm analysis identifies the Langmuir isotherm model as the best fit, with a correlation coefficient (R 2) of 0.9996 and adsorption capacity of 41.203 mg/g, suggesting monolayer adsorption dominance. This study establishes CUR-HCl-NZC as an effective, low-cost adsorbent for the removal of MB, offering a promising solution for water purification applications.