Increase In Initial Concentration Research Articles

Sustainable Photodegradation of Amoxicillin in Wastewater with a Nickel Aluminate and ZnO Heterosystem Oxides: Experimental and Gaussian Process Regression Modeling Studies

The wastewater generated by the pharmaceutical industry poses a risk to the environment due to undesirable characteristics such as low biodegradability, high levels of contaminants, and the presence of suspended solids, in addition to the high load of organic matter due to the presence of drugs and other emerging products in the effluent. This study aims to reduce the impact of wastewater pollution by removing amoxicillin (AMO) antibiotics as an organic pollutant. In this concept, two synthesized catalysts, NiAl2O4 and ZnO, are sensitive oxides to light energy. The prepared materials were then characterized using X-ray diffraction, UV–vis solid reflectance diffuse, Raman spectroscopy, scanning electron microscopy, BET, and ATR-FTIR spectroscopy. The effects of principal operating parameters under sunlight, namely, the percentage of the mixture of NiAl2O4 and ZnO, the pH of the medium, and the initial concentration of the antibiotic were studied experimentally to determine the optimal conditions for achieving a high degradation rate. The results showed that photodegradation is higher at a pH of 6, with a weight percentage of the mixture of 50% for both catalysts in 1 g/L of the total catalyst dose. Then, the effect of the initial concentration of AMO on the photodegradation reaction showed an important influence on the photodegradation process; as the degradation rate decreases, the initial AMO concentration increases. A high degradation rate of 92% was obtained for an initial AMO concentration of 10 mg/L and a pH of 6. The kinetic study of degradation established that the first-order model and the Langmuir–Hinshelwood (LH) mechanism fit the experimental data perfectly. The study showed the success of using heterosystem photocatalysts and sustainable energy for effective pharmaceutical removal, which can be extended to treat wastewater with other organic emerging pollutants. On the other hand, modeling was introduced using Gaussian process regression (GPR) to predict the degradation rate of AMO under sunlight in the presence of heterogeneous ZnO and NiAl2O4 systems. The model evaluation criteria of GPR in terms of statistical coefficients and errors show very interesting results and the performance of the model used. Where statistical coefficients were close to one (R = 0.9981), statistical errors were very small (RMSE = 0.1943 and MAE = 0.0518). The results suggest that the model has a strong predictive power and can be used to optimize the process of AMO removal from wastewater.

Decolorization of Acid Yellow 17 by ozonation and Peroxone (O3/H2O2) Process

In this study, the decolorization of Acid Yellow 17, a mono azo dye with a wide range of applications such as in food, textiles, personal care products, and household cleaning products, was investigated in aqueous solutions using ozonation and peroxone processes. The effects of ozone gas flow rate (150, 200, and 250 L/h), ozone gas concentration (5.5, 11, and 16.5 g/m3), initial dye concentration (100, 200, and 300 mg/L), and hydrogen peroxide concentration (25, 50 and 62.5 mg/L) on decolorization in the batch bubble reactor were investigated. When the ozone gas flow rate was increased from 150 L/h to 200 L/h in the ozonation process, the removal efficiency increased from 70% to 80.2%. At gas flow rates above 200 L/h, removal was negatively affected. The removal efficiency increased with increasing ozone gas concentration, and at the end of the 45-minute reaction time, a removal efficiency of 98% was achieved at an ozone gas concentration of 16 g/m3. The increase in initial dye concentrations decreases the removal efficiency due to the increase in the amount of pollutant per unit ozone molecule. In the peroxane process, the effect of hydrogen peroxide on color removal was limited. It was determined that the ozonation process was more effective for the removal of Acid Yellow 17 from aqueous solutions.

Removal of Phosphate from Water by Iron/Calcium Oxide-Modified Biochar: Removal Mechanisms and Adsorption Modeling

Phosphorus (P) pollution is a leading cause of water eutrophication, and metal-modified biochar is an effective adsorbent with the ability to alter the migration capacity of phosphorus. This study uses bamboo as the raw material to prepare metal-modified biochar (ZFCO-BC) loaded with Fe and Ca under N2 conditions at 900 °C, and investigates its adsorption characteristics for phosphate. Batch experimental results show the adsorption capacity of the ZFCO-BC gradually increases (from 4.0 to 69.1 mg/g) as the initial phosphate concentration increases (from 2 to 900 mg/L), mainly through multilayer adsorption. Additionally, as the pH increases from 1 to 7, the adsorption capacity of the ZFCO-BC climbs to reach its maximum value of 48.4 mg/g with an initial phosphate concentration of 150 mg/L. At this pH, phosphate primarily exists as H2PO4− and HPO42−, which both readily react with Fe3+ and Ca2+ in the biochar. Furthermore, the addition of CO32−, HCO3−, NO3−, SO42−, F−, and Cl− each affect the removal rate of phosphate by less than 10%, indicating the ZFCO-BC has a highly efficient and selective phosphate adsorption capacity. A multi-column adsorption experiment designed to achieve long-term and efficient phosphorus removal treated 275.5 pore volumes (PVs) of water over 366 h. The cyclic adsorption–desorption experiment results show that 0.5 M NaOH can effectively leach phosphate from the ZFCO-BC. Observations at the molecular level from P K-edge XANES spectra confirm the removal of low-concentration phosphate is primarily dominated by electrostatic attraction, while the main removal mechanism for high-concentration phosphate is chemical precipitation. This study demonstrates that ZFCO-BC has broad application prospects for phosphate removal from wastewater and as a potential slow-release fertilizer in agriculture.

Eco-Friendly Green Approach to the Biosorption of Hazardous Dyes from Aqueous Solution on Ragweed (Ambrosia artemisiifolia) Biomass

The presented research includes the preparation, characterization, and implementation of magnetic biosorbent (Fe3O4/RWB), obtained from ragweed (Ambrosia artemisiifolia) biomass. Fe3O4/RWB was examined for the removal of a hazardous dye, malachite green (MG), from an aqueous solution in a batch system. The effects of the experimental parameters—initial dye concentration (10–300 mg/L), contact time (0–120 min), biosorbent dose (1–5 g/L), initial pH (2–10), ionic strength (0–1 mol/L), and temperature (298–318 K) on dye biosorption—were studied. The results showed that increases in biosorbent dose, contact time, and initial pH led to an increase in biosorption efficiency, while the increase in initial dye concentration, the ionic strength, and temperature had the opposite effect. The biosorption kinetics for MG on Fe3O4/RWB were analyzed with pseudo-first-order, pseudo-second-order, and Elovich kinetic models, while the Langmuir, Freundlich and Temkin isotherm models were used for equilibrium data analysis. It was observed that the MG biosorption followed the pseudo-second-order kinetic model, whereas the Langmuir model was the best fit for the equilibrium biosorption data of MG, with a Qmax of 34.1 mg/g. the desorption of MG from Fe3O4/RWB indicated reusability in five adsorption/desorption cycles, good performance, and potential in practical applications.

Photocatalytic degradation of methylene blue using a Cu2+-modified bimetallic titanium-based metal organic framework (MIL-125) photocatalyst with enhanced visible light activity.

Cu-modified TiO2 nanoparticles derived from MIL-125 were prepared by solvothermal method for the photocatalytic degradation of methylene blue under visible light illumination. For boosting the photocatalytic performance as well as the physicochemical properties of bare sample, 2 wt % Cu2+ ions were integrated into the nodes of the MIL-125 framework. The results showed that incorporation of 2 wt % Cu2+ ions into the MOF framework had significant effects on the crystallographic structure and morphological and optical properties of photocatalytic samples, as well as catalytic activity for the methylene blue degradation reaction. The high activity profile of Cu-modified TiO2 nanoparticles derived from MIL-125 might be attributed to the increased thermal stability, lower band gap energy, and smaller crystallite size of the sample. Activity tests were carried out at five varying MB initial concentrations and four different pH values. According to the findings, an increase in initial dye concentration resulted in a decrease in degradation efficiency. It was observed that increasing the pH value in the range of 3-11 initially led to higher degradation rates until pH 7, after which the degradation rate began to decline.

Adsorption of silver ions onto chitosan hydrogel: Structural studies

Chitosan indicate a significant potential in the field of water treatment due to polymer high porosity, large specific surface area and its ability to bind strongly heavy metal ions form aqueous solutions. Therefore, chitosan based hydrogels have been fabricated by physical crosslinking of the polymer chains via sol–gel method using sodium β-glycerophosphate (β-GP) for silver ions (Ag) removal from water solutions. The aim of this study was to provide experimental studies under batch conditions to perform adsorption isotherm and evaluate the effect of silver adsorption onto chitosan hydrogel morphological and structural changes using SEM, XRD, FTIR and EDX analyses. Obtained results provides the data on the structural changes in the chitosan hydrogels under Ag adsorption process. The FTIR spectra confirmed that the C-NH2 and OH groups contribute to the formation of chitosan - silver ion complexes. The presence of adsorbed Ag in the samples < 0.8 gAgL−1 were evidenced by the characteristic peak at 2θ = 46.35°. Regarding to EDX analysis the adsorption efficiency toward Ag ions, rises with an increase in Ag initial concentration, resulting in L-type isotherm. The percentage removal of silver ions efficiency obtained 34 % for the highest Ag initial concentration (10 gAg L−1). SEM micrographs after Ag adsorption performed morphology as homogeneous porous network and reveals Ag present in the structure resulting from effective Ag adsorption. This study verified structural changes resulted from silver ions adsorption and confirmed the potential for thermosensitive chitosan hydrogels to applied as an adsorbent for water treatment applications.

The Staged Photocatalytic Reactor in the Removal of Acetaminophen: Aspects of Adsorption and Photocatalysis.

The efficiency of a staged photocatalytic reactor prototype was evaluated on a semi-pilot scale with the removal of acetaminophen, for which anatase particles were synthesized by Sol-Gel and impregnated on rectangular plates of clay. X-ray diffraction and Energy Dispersive X-ray Fluorescence patterns show that the final composite is made up of Al2O3 (14 %), SiO2 (41 %), CaO (3 %) TiO2 (34 %), and Fe2O3 (7 %). The impregnation method favors the dispersion of Anatase on the surface of the adsorbent. TiO2-Anatase/Clay, classified as a macro-porous solid with H3-type hysteresis loops by N2 physisorption. Adsorption processes are improved when using TiO2-Anatase/Clay compared to using TiO2-Anatase. The external mass transfer has a greater influence on the removal rate. The dimensionless parameters of the Biot number indicate there are no limitations due to the diffusive effect on the interior of the particle. The evaluation of the kinetic data under the Langmuir-Hinshelwood equation shows a decrease in efficiency as the initial concentration increases. The acetaminophen molecule shows destabilization in the structure of the aromatic ring with a visible decrease in the signals of this functional group evaluated by High-Performance Liquid Chromatography and Raman Spectroscopy.

Removal of Rare Earth Elements from complex mixtures by using manganese ferrite nanoparticles: Optimization through surface response methodology

The crucial role of Rare Earth Elements (REEs) in the development of hi-tech in addition to their limited availability have urged countries to develop sustainable alternatives to their conventional primary sources (ore mining). Sorption technologies using magnetic materials such as spinel ferrite nanoparticles provide efficient removal of REEs from contaminated solutions and ease of separation through application of an external magnetic field. However, there is still limited knowledge available regarding the optimal operational conditions in which to use these materials, especially in complex aqueous mixtures with different REEs. In this study, we have used Surface Response Methodology (SRM) applied to MnFe2O4 nanosorbents to identify their ideal sorption conditions of pH (4–8), REEs concentration (1–5 μM) and sorbent mass (20–180 mg L−1) in a mixture of nine REEs in water samples of distinct salinity (NaCl: 0–30 g L−1). Our results indicated that high pH favored REEs sorption because of the material's surface charge, which promoted interactions with REEs ions at pH 6–8. Yttrium was the least removed element, but total removal was achieved for lowest REEs concentration using 151 mg L−1 of sorbent. High removals were also obtained for the concentration of 5 μM (100 % removal, except for Y and La). Salinity did not impair sorption significantly (<10 %), which was owed to the high sorbent mass used in those assays. An increase in sorbent mass and initial REEs concentration also promoted faster kinetics. The spinel type MnFe2O4 nanoparticles showed great promise in a realistic application, which is the next proposed step in this line of research.

Dielectrophoretic separation of a water-in-oil emulsion

Electric field-assisted separation is considered one of the most effective ways of dehydrating water-in-oil emulsions. In the uniform electric field usually used in electrodehydrators, electrocoalescence leads to droplet enlargement, thus accelerating their gravitational settling. Meanwhile, using a nonuniform field is expected to provide an additional tool for phase spatial separation due to dielectrophoresis while keeping the conditions favorable for electrocoalescence. This study aims to investigate experimentally the dynamics of water-in-oil emulsion in a nonuniform electric field and the efficiency of its separation due to the dielectrophoretic effect. A high-frequency field and emulsions with zero-density contrast were used allowing us to study the action of the dielectrophoretic force in the absence of electrokinetic phenomena and gravitational settling. We found that droplets always move towards the electric field strength gradient, eventually accumulating at the internal electrode. We demonstrate that the separation efficiency increases as the average droplet size, the voltage, the dispersion medium permittivity, and the initial droplet concentration increase. In the latter case the separation enhancement is due primarily to droplet coalescence, the rate of which increases appreciably with increasing concentration. We demonstrate that all the experimental results can be combined into unified dependence based on a simple physical model.

KINETIC, ISOTHERM AND THERMODYNAMIC STUDIES OF THE ADSORPTION OF CRESOL RED DYE USING AGRICULTURAL WASTES

Agricultural wastes and plant biomass are alternative low-cost adsorbents because they can be used without or with a minimum processing. In the present study, batch experiments were carried out to study the adsorption of cresol red (CR) unto mango leaf (ML) and orange peel (OP). Several parameters that affect adsorption process such as pH, adsorbent dosage, contact time, initial dye concentration and temperature were investigated. FTIR and SEM were used to determine the functional group responsible for adsorption. The results revealed that the highest adsorption efficiency was at pH 5 for the two adsorbents. It was also discovered that CR removal efficiency increased with the increase in contact time and adsorbent dosage while adsorption capacity was higher with increase in initial dye concentration but removal efficiency was lowered. The kinetics conform with the pseudofirst-order kinetic model for mango leaf but conform with the pseudo-second-order kinetic for orange mesocarp due to the value of the correlation coefficient (R2). Based on the value of correlation coefficient, the experimental results for the removal by mango leaf best fitted the Langmuir isotherm model with monolayer adsorption capacity of 70.64 mg. g-1, while Freundlich isotherm model was best fitted to the experimental results for the adsorption of CR by Orange peel. The thermodynamic results revealed that the process is spontaneous and endothermic.

Experimental assessment of ozonated ice: Preparation, stability, and preservation effects on shrimp (Metapenaeus ensis)

Ozonated ice not only retains the inherent performance and function of ozone, but also serves as a cold source for food preservation. However, its preparation is challenging due to the low solubility and instability of ozone in water. So here, the major preparation techniques and the storage stability of ozonated water and ice were studied. Besides, the impact of ozonated ice treatment on the quality of shrimp (Metapenaeus ensis) was explored. To achieve these ends, a set of ozonated ice preparation devices was established, and the optimal conditions for producing ozonated water and ice were confirmed as follows: using 0 °C deionized water as the water source, achieving an outlet flow rate of 80 L/h, cyclically mixing gas-liquid twice, adding 1.0 g/kg of polyoxypropylene oxyethylene glycol ether (POGE), and freezing at −80 °C. Regarding ozone stability, an increase in initial ozone concentration and storage temperature, along with a decrease in water purity, resulted in a shorter half-life of ozone in water. Additionally, a lower storage temperature was conducive to prolonging the half-life of ozonated ice, while the addition of POGE had little effect. In practical application, under the optimal conditions for producing ozonated water and ice without POGE, shrimp stored in ozonated ice demonstrated superior sensory scores, whiteness values, and shear force compared to those stored in normal ice. Concurrently, they displayed reduced levels of TVC, TVB-N, and pH. Furthermore, the application of ozonated ice treatment mitigated blackening and improved odor quality. Consequently, this research offers a scientific foundation for the industrial application of ozonated water and ice and serves as a reference for preventing the deterioration and quality loss of shrimp and other seafood products.

Experimental study of methylene blue adsorption from aqueous solutions onto natural Algerian goethite

ABSTRACT The objective of this work is to study and model the methylene blue (MB) sorption, from aqueous solutions by goethite. The equilibrium time was reached during 10 min of agitation with 26.21 ℅ efficiency. MB removal efficiency is improved with an increased absorbent dose (0.5–08 g/L) for an initial 10 mg/L concentration. Treatment efficiency decreases with the increase of initial MB concentration (2–100 mg/L). The best adsorption yields were obtained in basic media. MB sorption kinetics via goethite leads to several results as to mechanisms that govern kinetics and isotherms equilibrium: Blanchard's model provides a better fit of the experimental results compared to Lagergren's model. Thus, the MB sorption kinetics is described by the pseudo-second order. Particle diffusion is involved in the MB removal mechanism, but it is not the only limiting step and the Boyd model application confirms that diffusion in the pores is the limiting step of the MB sorption process. The Elovich model is well verified and translated probably the existence of chemical-type interactions between MB and goethite. The study of MB adsorption isotherms showed that Freundlich, Temkin, and Elovich models are the best adapted than the Langmuir model. Finally, we can assess that goethite can be an interesting natural adsorbent for MB elimination from polluted waters in basic environments.

Adsorptive decolorization of brilliant green dye in aqueous media using various modified MOF-5 adsorbents

Dye pollution in environmental water is a serious problem worldwide, posing significant environmental and health concerns. To effectively address this problem, this study investigates the adsorptive decolorization of brilliant green (BG) dye in aqueous media by using various metal-organic frameworks (MOF-5)-based adsorbents modified with industrial wastes (coal fly ash (CFA) and rice husk ash (RHA)). The adsorption experiments were conducted to evaluate their performance under varying conditions, and the synthesized and spent adsorbents (selected) were characterized. The results showed that the adsorbent samples possessed the characteristics of a good adsorbent. MOF-5 coated with thermally treated RHA at 900 °C (MOF-5@ RHA900 – with BET surface area = 91.6810 m2 g−1) has the highest observed BG dye adsorption efficiency (92%) and adsorption capacity (30.22 mg g−1) at adsorbent mass of 1.4 g, contact time of 2 h, and initial dye concentration of 20 mg L−1. BG dye removal increased with an increase in contact time and adsorbent amount and decreased with an increase in initial dye concentration. The adsorption kinetics and isotherm equilibrium studies revealed that the adsorption data were best fitted to the pseudo-second-order kinetic model (R2 = 0.9507) and Langmuir isotherm model (R2 = 0. 0.9929), respectively. These findings highlight the potential of mesoporous MOF-5@ RHA900 as an effective adsorbent for BG dye decolorization in aqueous media, with implications for water treatment and the utilization of industrial waste materials.

Fixed Bed Column Adsorption System for the Removal of 2,4-Dichlorophenoxyacetic Acid Herbicide from an Aqueous Solution

The intensive use of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide has resulted in the presence of its residues in the environment, which leads to contamination of surface and groundwater. In this study, a fixed-bed column experiment was conducted for the removal of 2,4-D from an aqueous solution using termite mound soil (TMS). Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), atomic absorption spectrometry (AAS), and Brunauer–Emmett–Teller (BET) techniques were used to characterize the adsorbent. The effect of significant variables, such as the initial 2,4-D concentration (50 mg/L and 75 mg/L), flow rate (2.5 ml/min and 5 ml/min), solution pH (2, 4, and 6), and bed height (3, 6, and 9 cm), on the breakthrough characteristics of the adsorption system was assessed. In addition, the Thomas and Yoon–Nelson models were applied to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The findings showed that at a lower pH (2), a lower flow rate (2.5 ml/min), a lower 2,4-D concentration (50 mg/L), a higher bed depth (9 cm), and 840 min breakthrough time, a higher removal percentage (80.2%) of 2,4-D was achieved. The experimental data were in good agreement with the Thomas and Yoon–Nelson models. For the Yoon–Nelson model, the rate constant increased with an increase in the flow rate, initial ion concentration, and bed height. The time required for a 50% breakthrough decreased with an increase in the flow rate, bed height, and initial ion concentration. For the Thomas model, the rate constant increased with an increase in the flow rate but decreased with an increase in bed height and initial concentration. Overall, the study showed that termite mound soil in a fixed-bed column adsorption system presents an excellent potential for removing 2,4-D from aqueous solutions.

Enhanced heavy metal adsorption capacity of surface-functionalized Philippine natural zeolite in simulated wastewater

The adsorption efficiency of surface-functionalized Philippine natural zeolite (PNZ) for heavy metal uptake from single and mixed metal ion-simulated wastewater solution is reported in this work. Atomic adsorption spectroscopy (AAS) findings revealed that NaCl-modified PNZ (MPNZ) exhibited the highest zinc ion adsorption of 99.96 % while PNZ yielded an adsorption of 95.61 %. The adsorption isotherms of raw PNZ and MPNZ both show similar shapes that reflect Type IV adsorption-desorption isotherms with Type H2 hysteresis loop which can be observed for micro-mesoporous materials (pore containing 2–50 nm). An increase in PNZ pore size from 10.11 nm to 13.36 nm for NaCl-PNZ and 15.59 for NaOH-PNZ is observed after alkaline treatment. EDS confirmed the decrease in Si/Al ratio from 4.02 to 3.76, indicative of possible higher negative charge in the PNZ framework which is favorable for an enhanced Coulombic or electrostatic interaction with the cationic heavy metals being detected in this study. MPNZ demonstrated an adsorption capacity of 99.96 % for copper in mixed-ion solution while 88.49 % and 86.67 % were obtained for zinc and nickel, respectively. These values are higher compared to PNZ having only 32.21 % uptake for zinc and 38.00 % for nickel. A hierarchy of the average metal adsorption capacity showed the order: copper > nickel > zinc. Rapid adsorption at the first hour of the adsorption reaction was attained in all solutions while samples with pH 9 exhibited the highest Ni2+ and Zn2+ percent removal. Moreover, the increase in initial solution concentration led to lower adsorption efficiency and the maximum uptake was attained at 100 ppm. The equilibrium data of adsorption and mechanism were suitably described by Langmuir isotherm model. With these, surface functionalization of PNZ has further enhanced its cationic adsorption capacity on heavy metals in both single and mixed-ion solution having promising potential for wastewater remediation.

Bioremediation of Wastewater Contaminated with Dyes, Rhodamine B Using Alginate Immobilized Cell of Spirulina platensis

Bioremediation of wastewater contaminated with rhodamine B dyes using alginate immobilized cell of Spirulina platensis was studied. Factors affecting the dye adsorption such as pH, contact time, adsorbent dose, and initial dye concentration were investigated. The results showed that the optimum pH for dye adsorption was at 2 with an adsorption capacity of 0.86±0.00 mg/g. The adsorption was very rapid and reached equilibrium within 180 min with an adsorption capacity of 1.24±0.00 mg/g. Dye adsorption capacity by this alga was reduced at high adsorbent dose whereas the increase of initial concentration of dye increased the adsorption capacity. The adsorption isotherm correlated with Langmuir with the maximum adsorption capacity (qm) of 52.70±3.18 mg/g. Adsorption kinetic correlated with pseudo-second order. The adsorption rate limiting step were film diffusion rate and secondary rate of intraparticle diffusion. This study suggested that alginate immobilized cell of S. platensis can be applied for treatment of wastewater contaminated with rhodamine B.

Statistical physics investigation on the simultaneous adsorption mechanism of Cd2+ and Pb2+ on amino functionalized activated carbon derived from coal gasification fine slag

In this study, a novel surface amino-functionalized activated carbon (T-AC) was synthesized from coal gasification fine slag (CGFS) and used as an adsorbent for heavy metal ions. T-AC exhibits excellent adsorption capacity for Cd2+ and Pb2+. The adsorption process of Cd2+ and Pb2+ onto T-AC was found to be spontaneous. The dominant adsorption process was chemisorption, primarily involving chelation and covalent bonding. In binary systems, as the initial concentration increases, the independent adsorption effect of Pb2+ and Cd2+ gradually becomes a competitive adsorption effect. Statistical physical models revealed that the adsorption of T-AC for Cd2+ and Pb2+ in single systems followed a multi-molecular adsorption process, whereas in binary systems, it involved a multi-anchorage process. The adsorption capacity was primarily influenced by the number of ions attached to the receptor sites and the density of the adsorbent receptor sites. Moreover, elevating temperature enhanced the thermal movement of heavy metal ions within the pore structure of the adsorbent, reducing their tendency to aggregate at the active sites. This work provides insights into the microscopic-level adsorption process of heavy metal ions by carbon-based materials and contributed to understand of the adsorption behavior.

Box-Behnken Design for Photocatalytic Degradation of Sudan Black B by Catalyst-Embedded Multiwalled Carbon Nanotubes

This research employs a Box Behnken design-based technique for photocatalytic use of Multiwalled Carbon Nanotubes (MWCNTs) derived from spray pyrolysis. This procedure was used for photocatalytic degradation applications on Sudan black dye using Citrus limonum oil as a carbon precursor and Fe/Co/Mo supported on silica as a catalyst. The influence of initial dye concentration was compared to the effects of H2O2, catalyst concentration and solar light intensity. The Response Surface Methodology was used to optimize growth parameters for higher yield and graphitization. The as-grown CNTs were exemplified using scanning and transmission electron microscopy and Raman spectroscopy. This work resulted in the identification of the optimal set of spray pyrolysis turning parameters for achieving high CNT yield and effective decolorization of Sudan black B dye by employing MWCNTs as catalyst. The degree of decolorization of Sudan black B dye increases upto a certain level with an increase in initial H2O2 concentration and subsequently declines as excess H2O2 hydroxyl radicals formed serve as scavengers, resulting in less dye decolonization.

Study on removal performance of Fe3+ by biomass-based activated carbon and Liquefaction of Poplar Sawdust catalyzed by ferro activated Carbon

The adsorption experiment of iron ions on biomass based nut shell activated carbon was conducted to explore the adsorption capacity of iron ions on biomass based activated carbon and the key influencing factors: pH value, initial concentration of solution and adsorption time on the adsorption effect of activated carbon. The preparation of supported catalyst of activated carbon iron and its influence on the effect of catalytic liquefaction of poplar sawdust were investigated. The results showed that the optimal pH value of Fe3+ solution adsorbed by activated carbon was 5.0. The adsorption rate of activated carbon decreased with the increase of initial ion concentration, and the adsorption equilibrium of activated carbon reached at 250min. The optimum concentration of poplar sawdust liquefaction catalyzed by iron supported on activated carbon is between 6mg/L and 10mg/L.

Degradation performance and mechanism of microcystins in aquaculture water using low-temperature plasma technology

The eutrophication of aquaculture water bodies seriously restricts the healthy development of the aquaculture industry. Among them, microcystins are particularly harmful. Therefore, the development of technologies for degrading microcystins is of great significance for maintaining the healthy development of the aquaculture industry. The feasibility and mechanism of removing microcystins-LR by dielectric barrier discharge (DBD) plasma were studied. DBD discharge power of 49.6 W and a treatment time of 40 min were selected as the more suitable DBD parameters, resulting in microcystin-LR removal efficiency of 90.4%. Meanwhile, the effects of initial microcystin-LR concentration, initial pH value, turbidity, anions on the degradation effect of microcystin-LR were investigated. The removal efficiency of microcystin-LR decreased with the increase of initial microcystin-LR concentration and turbidity. The degradation efficiency of microcystin-LR at pH 4.5 and 6.5 is significantly higher than that at pH 8.5 and 3.5. HCO3− can inhibit the removal efficiency of microcystin-LR. Furthermore, five intermediates products (m/z = 1029.5, 835.3, 829.3, 815.4, 642.1) were identified in this study, and the toxicity analysis of these degradation intermediates indicated that DBD treatment can reduce the toxicity of microcystin-LR. e－aq, •OH, H2O2, and O3 have been shown to play a major role in the degradation of microcystin-LR, and the contribution ranking of these active species is e－aq > •OH > H2O2 > O3. The application of DBD plasma technology in microcystin-LR removal and detoxification has certain development potential.