Adsorption Of Indigo Carmine Dye Research Articles

Simple Synthesis and Characterization of Cobalt Ferrite Nanoparticles for the Successful Adsorption of Indigo Carmine Dye from Aqueous Media

Indigo carmine dye falls into the category of toxic chemicals, potentially leading to irritation and allergic reactions in certain individuals. Thus, this study employed the Pechini sol–gel strategy to easily produce CoFe2O4 nanoparticles, which serve as an effective adsorbent for the disposal of indigo carmine dye from aqueous solutions. The maximum adsorption capacity of CoFe2O4 for indigo carmine dye was determined to be 421.94 mg/g. The synthesized CoFe2O4 nanoparticles exhibited an average crystallite size of 18.75 nm. SEM analysis revealed that these nanoparticles were nearly spherical, with an average grain size of 198.32 nm. Additionally, TEM analysis indicated a fully agglomerated spherical morphology for the CoFe2O4 sample, with an average diameter of 15.37 nm. The EDS spectrum confirmed that the synthesized CoFe2O4 nanoparticles consisted of Co, Fe, and O elements, with respective weight percentages of 17.82%, 49.46%, and 32.72%. The removal of indigo carmine dye by the synthesized CoFe2O4 is spontaneous, chemical, exothermic, closely fitting the pseudo-second-order kinetic model, and demonstrating a strong concordance with the Langmuir equilibrium isotherm.

Improved pollutant management by kinetic and Box-Behnken design analysis of HDTMA-modified bentonite's adsorption of indigo carmine dye

The optimal performance characteristics of hexadecyltrimethylammonium-modified bentonite (HDTMA-B) for the removal of indigo carmine (IC, vat dye) from aqueous solution require a process parameter study. Using batch mode experiments and kinetic models, the study evaluated the adsorption behavior and dye-adsorbent interaction at different temperatures, adsorbent dosages, and initial dye concentrations. The rating mechanism for adsorption in ICs was found to be quite similar to the pseudo-second-order model. All of these IC dye removal adsorption parameters were optimized using a Box-Behnken surface statistical design with a pH of 6.6 as the starting point (as a fixed input parameter). At the 95% confidence level, the main effects of starting dye concentration and adsorbent dosage were both statistically significant, as was the square impact of initial dye concentration (ANOVA). There was a negative interaction between the adsorbent dose and the initial dye concentration, and this led to the discovery of a substantial detrimental effect. The primary factor in IC elimination was the initial dye concentration component (PC = 48.36%). At 34.28 °C and a starting dye concentration of 53.3 mg L-1, 0.97 g L-1 of adsorbent was optimal for removing 96.40% of IC from aqueous solutions, yielding a desirability of 1.00. The removal effectiveness of IC dye by HDTMA-modified bentonite could be predicted and the experimental parameters optimized using the simulated polynomial function. The regeneration capacity of the HDTMA-B adsorbent proves its importance in industrial wastewater treatment.

Adsorption of Indigo Carmine Dye and Copper Ion by Kaolin from Bangka Island

Indigo Carmine (IC) is a synthetic dye that might promote irritations, vomiting, and diarrhea when orally consumed in high concentrations. Copper is a dangerous heavy metal that tends to accumulate in organisms' cells as a pollutant. Hyperproduction of IC and accumulation of copper in water could cause an environmental problem that must be adequately addressed. Kaolin is found abundant on Bangka Island. Based on XRD analysis, Kaolin Island from Bangka Island consists of two important minerals, Kaolinite and Rectorite. Kaolin has chemical and physical properties, which make it useful in several applications, including as an adsorbent. This study aims to evaluate how Kaolin can adsorb copper ion from acid wastewater (pH < 0.5) and determine natural Kaolin's ability to adsorb IC dye from an aqueous solution. Many factors, including mixing time and number of doses of Kaolin, influence Kaolin's ability to absorb IC. The longer the stirring time, the more IC is absorbed. The optimal temperature for IC adsorption is 25˚C. The optimal kaolin dose for IC adsorption is 20% (m/v). Copper concentration after application of Kaolin tends to decrease, with optimal at 25.09% (m/v) dosage for 19.23% copper removal.

Adsorption of Indigo Carmine Dye by Acacia nilotica sawdust activated carbon in fixed bed column

A continuous mode fixed-bed up-flow column adsorption analysis was conducted utilizing Acacia nilotica sawdust activated carbon (ASAC) as an adsorbent for the adsorption treatment of toxic Indigo Carmine Dye (ICD). The effect on the adsorption characteristics of ASAC of the influent ICD concentration, flow rate, and column bed depth has been investigated. According to the column study, the highest efficiency of ICD removal was approximately 79.01% at a preliminary concentration of 100 mg/L with a flow rate of 250 mL/h at a bed depth of 30 cm and adsorption power of 24.67 mg/g. The experimental work confirmed the dependency of break-through curves on dye concentration and flow rate for a given bed depth. Kinetic models were implemented by Thomas, Yoon–Nelson, and Bed-depth-service-time analysis along with error analysis to interpret experimental data for bed depth of 15 cm and 30 cm, ICD concentration of 100 mg/L and 200 mg/L and flow rate of 250 mL/h, and 500 mL/h. The analysis predicted the breakthrough curves using a regression basin. It indicated that all three models were comparable for the entire break-through curve depiction. The characteristic parameters determined by process design and error analysis revealed that the Thomas model was better followed by the BDST and Yoon–Nelson models in relating the procedure of ICD adsorption onto ASAC. B-E-T surface area and B-E-T pore volume of ASAC were 737.76 m2/g and 0.2583 cm3/g, respectively. S-E-M and X-R-D analysis reveal the micro-porous and amorphous nature of ASAC. F-T-I-R spectroscope indicate distinctive functional assemblies like -OH group, C–H bond, C–C bond, C–OH, and C–O groups on ASAC. It could be computed that the ASAC can be used efficiently as an alternative option for industrial wastewater treatment

Non-linear modelling of the adsorption of Indigo Carmine dye from wastewater onto characterized activated carbon/volcanic ash composite

Over the past couple of years, the resurgence of placing an effective and sustainable amendment to combat against the auxiliary industrial entities like Indigo Carmine (IC), remains a highly contested agenda from a global point. The birth of non-linear modelling for these auxiliary entities is also of significant interest in order to avoid loss of some useful information. With the renaissance of activated carbon (AC), the AC prepared from palm kernel shells (PKSAC) and composite prepared by combining the PKSAC and porous volcanic ash (BVA) from the foot of active volcanic mountain of Cameroon will be of significant contribution for ever increasing pollution problems. Non-linear modelling method was used to model the uptake capacity by adsorption process of IC onto PKSAC and PKSAC/BVA composite. Effects of contact time (0–60 min), adsorbent dose, pH of solution and initial dye concentration (10–20 ppm) were studied on the quantity removal of the hazardous IC dye from aqueous solution in a batch experiment. The prepared PKSAC and PKSAC/BVA composite were characterized using Nitrogen adsorption at 77 K (BET), Fourier transform Infrared spectroscopy (FTIR), Sacanning electron microscopy with energy dispersive X Ray (SEM-EDX), and particle size. The optimum IC uptake was 11.025 and 12.642 mg/g for PKSAC and PKSAC/BVA composites adsorbent respectively. Four Isotherms and kinetic non-linear regression models each were used to model the adsorption data. It results that for the isotherm models, the Langmuir and Freundlich isotherm models best fitted the adsorption phenomenon while pseudo-first and pseudo-second order kinetic models well described the adsorption mechanism. Furthermore, the adsorption speed constant (α) of the Elovich kinetic model being higher than the desorption coefficient (β) implies chemisorption was the dominant mechanism in the adsorption process. The composite shows 14.67% higher in retention capacity of the IC dye than the pristine carbon. Conclusively, the expanding of activated carbon/volcanic ash composite represents a potentially viable and powerful tool, leading to the plausible improvement of environmental preservation.

Removal of indigo carmine (IC) in aqueous solution onto activated pomegranate peel (APP) by adsorption process: Kinetic and thermodynamic studies

The adsorption of indigo carmine dye onto Activated Pomegranate Peels (APP) from aqueous solutions was followed in a batch system. The adsorbent was characterized by the BET method (specific surface area SBET: 51.0674 m2/g) and point of zero charge (pHpz = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of pomegranate peels (APP) such as the initial dye concentration (10–60 mg/L), solution pH (2–12), adsorbent dose (1–10 g/L), agitation speed (100–600 rpm), and temperature (298–308 K). The best adsorption capacity was found at pH 2 with an adsorbent dose 1 g/L, an agitation speed 300 rpm and a contact time of 45 min. The adsorption mechanism of IC onto (APP) was studied by using the first-pseudo order, second-pseudo order, Elovich, and Webber-Morris diffusion models. The adsorptions kinetic were found to follow rather a pseudo-second order kinetic model with a determination coefficient ( R2) of 0.999. The equilibrium adsorption data for IC onto (APP) were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with capacities ( qmax of 158.73 mg/g at 298 K). The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy; enthalpy and entropy to predict the nature of adsorption process. The negative values Δ G° and Δ H° indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent elaborated from pomegranate peels material was found to very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low cost preparation, and good adsorption capacity.

Adsorption of Indigo Carmine Dye onto Porous Adsorbent Derived from Banaba Peels Waste

This study investigated the preparation method and adsorption efficiency of porous adsorbents prepared from banana peels (BP) waste. The BP waste was acquired from banana fried chip factories in Sukhothai province. Chemical activation by sulfuric acid was used to activate the raw material, followed by carbonization at 500 °C. The activated BP adsorbent has been characterized by energy dispersive X-ray spectrometer (EDXRF), N2 adsorption-desorption isotherms (BET), scanning electron microscopy (SEM), and zeta potential measurements. The analysis of chemical properties showed that it mainly contained 70.39 % K matter. The specific surface area of the BP sample reached 215.05 m2/g under acid activation and thermal treatment. The SEM images showed the morphologies of the BP adsorbent before and after activation. There was a significant change in the morphology and in the dried BP and activated BP. The pHPZC value of the activated BP obtained under optimal conditions was 4.13. Adsorption of indigo carmine (IC) onto porous activated BP at different initial IC concentrations (10 - 100 mg/L) and contact times (30 - 120 min) was investigated using batch experiments (0.1 g/50 mL). At an optimum contact time of 60 min, maximum adsorption capacity was determined at 56.18 mg/g. The Freundlich isotherm model with a high correlation coefficient was used to describe multilayer adsorption. The kinetic study fit well with a pseudo second-order kinetic model that represented chemisorption. The negative deltaG° value of –14.64 kJ/mol indicated that adsorption of IC onto the BP adsorbent was spontaneous in nature at 305.15 K. HIGHLIGHTS Increase the value of the biomass resources was produced form banana peels as high surface area adsorbent The qmaxfor indigo carmine (IC) adsorption was 56.18 mg/g under optimized conditions The adsorption of the IC follows the Freundlich model and pseudo-second order kinetic model Negative deltaG° value indicated the possibility of IC adsorption process GRAPHICAL ABSTRACT

Adsorption of Indigo Carmine Dye onto Physicochemical-Activated Leaves of Agave Americana L

Dyes represent a serious threat to the environment when released in wastewaters. Hence, the main objective of this work was to design and fabricate an activated carbon from an invasive plant – Agave Americana L – capable of removing indigo carmine in aqueous solutions. The equilibrium adsorption of indigo carmine was assessed using the Freundlich, Langmuir and Dubinin-Radushkevich isotherm model.The zinc chloride was used to activate the powder of Agave at 600 °C and 900 °C. The results of this work showed that the elaborated activated carbon had a maximum adsorption of 61.72 mg/g and a specific surface area of 38 m²/g determined using the BET method. The thermodynamic study showed that the adsorption of indigo carmine on the activated carbon was endothermic. Therefore, the activated carbon prepared from the Agave Americana L would be an efficient and cost effective alternative adsorbent of indigo carmine and would have a positive effect on the environment.

Synthesis and Structural Studies of Manganese Ferrite and Zinc Ferrite Nanocomposites and Their Use as Photoadsorbents for Indigo Carmine and Methylene Blue Dyes.

Solar-moderated adsorptions of indigo carmine and methylene blue dyes were investigated using manganese and zinc ferrite capped with biochar prepared from the root of Chromolaena odorata. TEM micrograph of the as-prepared manganese ferrite nanocomposites (MnFe2O4@BC) revealed octagonally shaped particles with an average size of 42.64 nm while the zinc ferrite nanocomposite (ZnFe2O4@BC) micrograph revealed mixtures of rod- and cone-shaped particles with an average size of 43.82 nm. Biochar capping of MnFe2O4@BC reduced the band gap from 3.63 to 2.08 eV. The nanocomposite surface areas were 197.64 and 92.14 m2/g for MnFe2O4@BC and ZnFe2O4@BC, respectively. Photoadsorption of the as-prepared nanocomposites showed that 10 mg of ZnFe2O4@BC effectively removed 69.07 and 98.60% of 70 mg/L indigo carmine and methylene blue dyes while MnFe2O4@BC removed 77.65 and 94.83% of indigo carmine and methylene blue dyes after 2 h of equilibration under visible light irradiation, respectively. The nonlinear form of the Langmuir isotherm had a better approximation to the experimental solid-phase concentration (qe) for the adsorption of indigo carmine dye using both nanocomposites. In contrast, the linear form gave a better goodness-of-fit for the adsorptions of methylene blue dye. The manganese ferrite (MnFe2O4@BC) and zinc ferrite (ZnFe2O4@BC) nanocomposites showed no inhibition of Escherichia coli and Staphylococcus aureus, which indicates that they could be used for both biological and environmental applications.

Activated carbonaceous materials from tea waste and its removal capacity of indigo carmine present in solution: synthesis, batch and optimization study

The present work determines efficiency of domestic food waste like tea waste in removing indigo carmine from synthetic textile wastewater. Carbonaceous material (tea waste) has been employed and it showed removal percentage of indigo carmine at 90% through adsorption process. Carbonaceous material was chemically activated by using modified Hummer’s method and it was observed through Scanning Electron Microscopic image, Fourier Transform Infrared Spectrometer, X-ray diffractometer and Brunauer, Emmett and Teller analysis that revealed that the modified biochar is comparably similar to graphene oxide (GO). Various experimental parameters are evaluated for the removal efficiency of the synthesized adsorbent under the present study. Results of the experiments performed using the GO-like adsorbent synthesized from tea waste confirmed potential efficiency of adsorption of indigo carmine dye from synthetic waste water solution. The adsorption mechanism has been analysed by fitting the experimental data in different adsorption isotherm and kinetic models. The results indicated that the adsorption followed Langmuir isotherm model with maximum uptake of 20 mg g− 1 and pseudo second order kinetic model with the best correlation coefficient. The thermodynamic study showed the dye removal to be spontaneous and endothermic.

Adsorption of Indigo Carmine dye onto the surface-modified adsorbent prepared from municipal waste and simulation using deep neural network

A new adsorbent was prepared from municipal wastes (a mixture of Corn Stover, Paper Waste, and Yard Waste) by cationization with 3 ̶ Chloro ̶ 2 ̶ Hydroxypropyl Trimethylammonium Chloride. The FTIR spectrum confirmed the quaternary ammonium group's presence on the adsorbent surface (1450 cm−1). The maximum adsorption capacity (148 mg/g) was higher than the earlier reported values. Liu isotherm described well the adsorption process, with a high R2adj value (0.997). The pseudo-first-order equation fits well for kinetic data, and thermodynamic experiments demonstrated the endothermic nature of the adsorption. The deep neural network (DNN) is applied to simulate the adsorption process, which outperformed the classical machine learning and shallow neural network models. The DNN model predicted accurately the adsorption process with the lowest deviation from the actual values with Mean Absolute Error (MAE = 3.2), Root Mean Squared Error (RMSE = 4.89), and the highest performance accuracy of R2 (0.96) as compared to various classical ML algorithms such as Linear Regressions (MAE = 12.53, RMSE = 18.01, R2 = 0.42), Random Forest (MAE = 5.81, RMSE = 10.05, R2 = 0.82), and Extra Trees (MAE = 4.35, RMSE = 8.22, R2 = 0.88). The utilized DNN model can be used for predicting the removal efficiency of dyes for various combinations of input parameters without going through laboratory experiments.

Adsorption of Indigo Carmine Dye by Composite Activated Carbons Prepared from Plastic Waste (PET) and Banana Pseudo Stem

This study is on the adsorption of indigo carmine dye by composite activated carbons prepared from banana pseudo stems and plastic waste. The activated carbons named TB1P1, TB1P1h and TB2P1 were obtained by pyrolysis at 700°C under steam of raw materials at different ratios (1:1 and 2:1). They were characterized by different techniques such as SEM/EDX, Raman Spectroscopy, FTIR, XRD, TGA/DTA and BET/BJH. Analyses indicate amorphous structures with specific surface areas of 424.37; 385.45 and 338.84 m2/g for TB1P1, TB1P1h and TB2P1 respectively. The study of the adsorption of indigo carmine dye by these adsorbents was carried out by varying parameters such as contact time, mass of adsorbent and initial concentration of the dye. The maximum retention is 94.71%, 86.18% and 84.17% for TB1P1, TB1P1h and TB2P1 respectively after 60 min of stirring, for a pH = 4.6 using 0.6 g of adsorbents. The adsorption of indigo carmine follows well, the Langmuir model, with the most suitable kinetics as pseudo second order.

Adsorption and anion exchange insight of indigo carmine onto CuAl-LDH/SWCNTs nanocomposite: kinetic, thermodynamic and isotherm analysis.

Two-dimensional layered materials are gaining much attention in the field of wastewater purification. Herein, we report the synthesis and characterization of an anion selective copper–aluminum-layered double hydroxide/single-walled carbon nanotubes (CuAl-LDH/SWCNTs) composite for the scavenging of organic dye indigo carmine (IC) from aqueous solution. A facile urea hydrolysis method was used for the controlled growth of the metal hydroxides over the SWCNTs. Structural characterization of the prepared materials was investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The obtained results revealed that the CuAl-LDH/SWCNTs composite has a higher potential for the removal of IC in comparison to CuAl-LDH and SWCNTs. The enhanced adsorption capacity of the composite revealed that deposition of CuAl-LDH over SWCNTs increases the active adsorption sites and promotes the interactions between the composite and IC dye via anion exchange, electrostatic, π–π, hydrogen bonding etc. Moreover, adsorption kinetics, isotherms, and thermodynamic studies have been also proposed to illustrate the mechanism of the IC adsorption onto the CuAl-LDH/SWCNTs composite. Thermodynamic parameters showed that the adsorption of IC dye onto the CuAl-LDH/SWCNTs composite was exothermic and spontaneous in nature. Intra-particle diffusion was determined to be the rate-limiting step and adsorption of IC followed the Langmuir isotherm model with the maximum monolayer adsorption capacity 294.117 mg g−1 at 20 °C. The results suggest that the CuAl-LDH/SWCNTs composite is a potential material for IC adsorption in aqueous solution.

An efficient adsorption of indigo carmine dye from aqueous solution on mesoporous Mg/Fe layered double hydroxide nanoparticles prepared by controlled sol-gel route

A new approach for removal of indigo carmine blue (IC) dye which is extensively used in jeans manufacture was successfully performed on novel mesoporous [LDH] nanoparticles prepared by sol-gel route using CTAB as shape and pore directing agent. The physicochemical features were monitored by X-ray diffraction (XRD), Fourier transformer infra-red (FTIR), N2 adsorption-desorption isotherm, Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). The influence of reaction parameters affecting dye adsorption including contact time, initial dye concentration, pH and temperature were investigated. Textural analysis and HRTEM images indicate the existence of mesoporous spherical nanoparticles of size = 26 nm connected to each other's and embedded large numbers of mesopores of average pore radius = 43.5 Å. A successful adsorption of IC on LDH nanoparticles of surface area = 85.6 m2/g at various pH with maximum adsorption capacity = 62.8 mg/g at pH = 9.5. Langmuir model is more favorable to describe the adsorption of IC rather than Freundlich model which reflecting the preferential formation of monolayer on the surface of LDH. Both film diffusion and the intraparticle diffusion affect the dye adsorption. The values of enthalpy change (ΔH) for and (ΔS) are + 28.18 and + 0.118 kJ/mol, respectively indicating that the removal process is endothermic. The results indicated that LDH nanoparticles conserved a good activity even after five consecutive cycles of reuse. Our results suggest that mesoporous LDH nanoparticles are considered a potential novel adsorbent for remediation of wastewater containing IC.

Calcium hydroxide as low cost adsorbent for the effective removal of indigo carmine dye in water

Adsorption of indigo carmine dye onto calcium hydroxide was investigated in this work. The variation in the pH, adsorbent dose, dye concentration, duration and the temperature was evaluated. Adsorption of indigo carmine dye onto calcium hydroxide was effective at pH 12 (50min) and follows Langmuir-type isotherm behaviour. The adsorption process follows pseudo-second order rate kinetics. Enthalpy, entropy, free energy and the activation energy parameters have been reported.

Hydrothermal synthesis of nano cavities of Al-MCF for adsorption of indigo carmine from aqueous solution

Aluminum mesocellulous silica foam (Al-MCF) was synthesized by pH-adjusting with hydrothermal method. Nano cavities of Al-MCF were characterized with FTIR, XRD and TEM methods. BET was done with N2-adsorption experiments and is showed the surface area 665.56m2/g. TEM of Al-MCF was shown the particles diameters are pH dependent. Al-MCF particles were use d for adsorption of indigo carmine dye from aqueous solution. The sorption kinetics was found to follow a pseudo-second order kinetic model. The thermodynamic parameters were evaluated. The adsorption of IC onto Al-MCF foam was exothermic and negative value of ΔG° confirms the spontaneous process.

HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF NANO SIZED ZSM-5 AND THEIR EFFECT ON THE DECOLORIZATION OF INDIGO CARMINE DYE

Silica sources can influence different effects of ZSM-5 crystallization and it leads to change in the properties of the final product. The crystallinity of nanosized ZSM-5 zeolite from precursors mixtures containing different silica sources, e.g. tetraethylorthosilicate (TEOS), colloidal silica (CS), silicic acid(SA) and fumed silica(FS) have been studied. The produced samples are investigated using XRD, SEM, FT-IR, pyridine adsorption and N2 adsorption measurements. XRD results show that the product obtained by different silica sources is nano sized ZSM-5 phase. SEM results show that silica sources influences on shape of the produced ZSM-5; the sample which was prepared by silicic acid crystallized in spherical shape crystals, the samples which was prepared by TEOS crystallized in cubical shape crystals, the sample which was prepared by colloidal silica crystallized in spherical shape crystals with smaller aggregated but the sample which was prepared by fumed silica crystallized in round shape crystals. N2 adsorption results show thatsilica sources influences on pore diameter and pore volume of the produced ZSM-5.The adsorption of indigo carmine dye by ZSM-5 has been studied. It was found that the synthesized zeolite by SA exhibited significantly higher adsorption capacity for indigo carmine than other ZSM-5 states due to the difference in morphological properties. The optimum ZSM-5 loading is 1 g at pH 4 after 180 min.

Synthesis and characterization of MnO x/TiO 2 nanoparticles for photocatalytic oxidation of indigo carmine dye

Manganese (10 wt.%) supported on titania synthesized by sol–gel (Mn/TiO 2SG) and impregnation (Mn/TiO 2D-imp) methods in addition to their precursors TiO 2SG and TiO 2D (Degussa) materials were characterized by measuring the surface texturing, Fourier transform infrared spectroscopy, X-ray diffraction, particle size (analyzer) and electrophoretic mobility (zeta potential). These materials were tested for adsorption and mineralization (in the presence of UV irradiation) of indigo carmine (IC) dye. Through comparison of the results, the photocatalytic degradation of Mn/TiO 2D-imp indicated the highest activity (98%) comparatively. This was due to 34% of the support titania is covered by Mn species in Mn/TiO 2D-imp mainly as Mn 2O 3 moieties, as validated from IR results (605, 714 cm −1). On the other hand, Mn in Mn/TiO 2SG was incorporated in titania lattice mainly in tetrahedral coordination sites as β-MnO 2 (655, 693 cm −1) and only exposes surface coverage comprises of 10%. The adsorption of IC dye onto TiO 2D was considerably higher (88%) than rest of materials due to increasing OH groups, large surface to volume ratio and moderate pore radius (33 Ǻ) that was accessible to facile IC diffusion. TiO 2SG and Mn/TiO 2SG presented lower activity either in adsorption and photocatalysis compared with Mn/TiO 2D-imp. There is no apparent size effect on IC degradation over former catalysts since they have comparable values (48–43 nm). The influence of time on the decolorization rate of IC on Mn/TiO 2-Dimp was thoroughly investigated and well pH regulated and correlated with ZPC of MnO x species and surface properties.