Higher Adsorption Percentage Research Articles

Synthesis, characterization and performance of a polycarboxylate superplasticizer with amide structure

The amide-structural polycarboxylate superplasticizers (amide-PCEs) were synthesized by amidation reaction between polyacrylic acid (PAA) and amino-terminated methoxy polyethylene glycol (amino-PEG) under different conditions, and the effects of amide-PCE's synthesis on amidation rate and flow performance of cement paste were investigated. Fourier Transform Infrared Spectroscopy (FTIR), 1H Nuclear Magnetic Resonance (1H NMR), and molecular-weight measurements were used for structural characterization, and the results confirmed ideal amide structure and sufficient amidation reaction. Amide-PCE with the carboxyl–amino ratio of 4:1 exhibited the lowest surface tension, highest adsorption percentage, and the best paste fluidity results. Based on the above results, the dispersion and adsorption mechanisms of amide-PCE in cement–water system were discussed. The application performances in concrete showed that amide-PCE had similar slump to that of conventional PCE, but also had better air-entraining ability, bubble retention and concrete frost-resistance than those of conventional PCE. Depending on this amide structure and good performances, amide-PCE shows broad application prospects.

Removal of Reactive Dye using Activated Carbon from Agricul-tural Waste

Activated carbon produced from agricultural waste, namely tapioca peel, was used for the adsorption of reactive dye Turquoise Blue H5G from its aqueous solutions. The preparation of activated carbon from agricultural waste would increase economic returns and reduce pollution. In this project, adsorption studies were performed by varying parameters such as dye concentration, pH of the dye solution and contact time. The equilibrium adsorption data obtained were used to calculate the Freundlich and Langmuir isotherm parameters. The study investigates the removal of Turquoise Blue H5G dye from its aqueous solution. Higher adsorption percentages were observed at lower concentrations of Turquoise Blue H5G. Optimum pH value for dye adsorption was determined as 7. Maximum dye was removed within 120 min from the start of every experiment.

Cr(VI) Adsorption and Desorption on Soils and Biosorbents

We study the adsorption and desorption of chromium on two soils (a forest soil and a vineyard soil), both individually or after being combined with ground mussel shell, and on various materials (mussel shell, pyritic material from a dump site, and slate processing fines). The adsorption capacity depends mainly on the initial Cr concentration, on the pH, and on the abundance of noncrystalline Fe. The highest adsorption percentage (94 %) corresponds to the pyritic material, which also shows very low desorption rates (1.4 %), has the lowest pH, and has the highest concentration of noncrystalline Fe. The adsorption isotherms in most cases fit the Freundlich and Lineal models, rather than the Langmuir model, with no easily predictable maximum for chromium adsorption.

Adsorption of some metal complexes derived from acetyl acetone on activated carbon and purolite S-930

A new Schiff base (HL) derived from condensation of p-anisidine and acetyl acetone has been prepared and used as a chelating ligand to prepare Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) complexes. The study of the nature of these complexes formed in ethanol solution following the mole ratio method (2:1, L:M) gave results which were compared successfully with these obtained from isolated solid state studies. These studies revealed that the complexes having square planner geometry of the type (ML2), M=Co(II), Ni(II) and Cu(II), and octahedral geometry of the type [CrIIIL2(H2O)2]Cl and [MNIIL2(H2O)2]. The adsorption studies of three complexes Cr(III), Mn(II), and Co(II) on activated carbon, H and Na-forms of purolite S-930 resin show high adsorption percentage for Cr(III) on purolite S-930 due to ion exchange interaction compared with high adsorption of neutral Mn(II), Co(II) complexes on activated charcoal. Linear plot of log Qe versus log Ce showed that the adsorption isotherm of these three complexes on activated carbon, H and Na-forms of purolite S-930 surface obeys Freundlich isotherm and was similar to S-curve type according to Giles classification which investigates heterogeneous adsorption. The regression values indicate that the adsorption data for these complexes fitted well within the Freundlich isothermal plots for the concentration studied. The accuracy and precision of the concentration measurements of these complexes were determined by preparing standard laboratory samples, the results show relative error ranging from ±1.08 to 5.31, ±1.04 to 4.82 and ±0.28 to 3.09 and the relative standard deviation did not exceed ±6.23, ±2.77 and ±4.38% for A1, A2 and A3 complexes, respectively.

Biosorption Studies for the Removal of Malachite Green from its Aqueous Solution by Activated Carbon Prepared from Cassava Peel

The association of dyes with health related problems is not a new phenomenon. The effectiveness of carbon adsorption for dye removal from textile effluent has made it an ideal alternative to other expensive treatment methods. The preparation of activated carbon from agricultural waste could increase economic return and reduce pollution. Cassava peel has been used as a raw material to produce activated carbon. The study investigates the removal of malachite green dye from its aqueous solution. The effects of condition such as adsorbent dosage, initial dye concentration, pH and contact time were studied. The adsorption capacity was demonstrated as a function of time for malachite green from aqueous solution by the prepared activated carbon. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly. Higher adsorption percentages were observed at lower concentrations of malachite green dye. Silver nitrate treated cassava peel showed a better performance compared to Sulphuric acid treated and raw carbons, thus making it an interesting option for dye removal textile effluent.

Adsorptive removal of Megenta MB cold brand reactive dye by modified activated carbons derived from agricultural waste

The activated carbon produced from agricultural waste, Tapioca Peel, was used for the adsorption of reactive dye Megenta MB from its aqueous solutions. The preparation of activated carbon from agricultural waste could increase economic return and reduce pollution. In our project, adsorption studies were performed by varying parameters such as dye concentration, pH of the dye solution and contact time. The study investigates the removal of Megenta MB dye from its aqueous solution. The equilibrium adsorption data obtained were used to calculate the Freundlich and Langmuir isotherm parameters. Higher adsorption percentages were observed at lower concentrations of Megenta MB. Optimum pH value for dye adsorption was determined as 7. Maximum dye was removed within 120 min after the beginning for every experiment. Keywords: Tapioca peel; Megenta MB; effluent treatment, textile dye, water pollution, environment, industry, India

Adsorptive Removal of Megenta MB Cold Brand Reactive Dye by Modified Activated Carbons Derived from Agricultural Waste

The activated carbon produced from agricultural waste, Tapioca Peel, was used for the adsorption of reactive dye Megenta MB from its aqueous solutions. The preparation of activated carbon from agricultural waste could increase economic return and reduce pollution. In our project, adsorption studies were performed by varying parameters such as dye concentration, pH of the dye solution and contact time. The study investigates the removal of Megenta MB dye from its aqueous solution. The equilibrium adsorption data obtained were used to calculate the Freundlich and Langmuir isotherm parameters. Higher adsorption percentages were observed at lower concentrations of Megenta MB. Optimum pH value for dye adsorption was determined as 7. Maximum dye was removed within 120 min after the beginning for every experiment.

Adsorption of Chrysoidine R by using fly ash in batch process

This investigation deals with effective utilization of fly ash as adsorbent for the removal of Chrysoidine R from the aqueous solution. The fly ash is a major byproduct generated in coal-based thermal power plants and has good potential for use as an adsorbent. A series of experiments were carried out in a batch adsorption technique to obtain the effect of process variables viz. contact time, pH (2, 4, 6 and 8) initial concentration of the dye (400, 600, 800 and 1000 mg L −1), amount of the adsorbent (125, 250, 375 and 500 mg L −1), and temperature (303, 313, 323 and 333 K) on adsorption. The concentration of dye was determined by spectrophotometer. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly; higher adsorption percentage was observed at lower concentration of chrysoidine. The adsorption data were analyzed using Langmuir and Freundlich isotherms. The adsorption was found to obey pseudo-first order kinetics. An intra particle diffusion model was used to fit the experimental data. The thermodynamic parameters such as standard change in free energy, enthalpy and entropy of adsorption have been calculated. Adsorption of Chrysoidine R on fly ash was found to be an exothermic reaction.

Comparison of azo dye degradation efficiency using UV/single semiconductor and UV/coupled semiconductor systems

This study examined degradation of azo dyes using photocatalytic oxidation (UV/semiconductor). The model substrates employed in this work were Procion Red MX-5B and Amaranth, while the photocatalysts were TiO 2, ZnO, and SnO 2. UV–Vis spectrum analysis demonstrated that the band gap energies of TiO 2, ZnO, and SnO 2 were 3.17, 2.92, and 4.13 eV, respectively. The band gap energy of SnO 2 is insufficient to initiate photocatalytic reaction after UV irradiation (365 nm). The reaction rate constants fit a first-order reaction model and the reaction rate constant of Procion Red MX-5B for TiO 2 + SnO 2 (0.31 h −1) is larger than that of TiO 2 (0.24 h −1) and SnO 2 at pH 10. The difference between the conduction bands of SnO 2 and TiO 2 enables the former to act as a sink for the photogenerated electrons. Most of the reaction rate constants had higher values at pH 10 than pH 7, and thus the OH attack could be assumed to represent the main reaction in this investigation. The quantities of sulfate and chloride ions released are below stoichiometry during the degradation. Owing to the sulfonate groups of Amaranth exceeding Procion Red MX-5B, Amaranth had larger electrostatic attraction than Procion Red MX-5B with the surface of ZnO, and also had higher adsorption percentage than Procion Red MX-5B on the surface of ZnO. The trend of adsorption is consistent with the reaction rate constant at pH 7, namely Amaranth > Procion Red MX-5B. The sulfate dissociation rate constant of Amaranth in UV/ZnO at pH 7 (0.49 h −1) approaches the overall rate constant (0.53 h −1); therefore, the first step involved in Amaranth can be suggested to the cleavage of the bonds of the C–S in Amaranth, causing sulfate ion formation.

Basic dye (methylene blue) removal from simulated wastewater by adsorption using Indian Rosewood sawdust: a timber industry waste

Dyes are usually present in trace quantities in the treated effluents of many industries. The effectiveness of adsorption for dye removal from wastewaters has made it an ideal alternative to other expensive treatment methods. This study investigates the potential use of Indian Rosewood ( Dalbergia sissoo) sawdust, pretreated with formaldehyde and sulphuric acid, for the removal of methylene blue dye from simulated wastewater. The effects of different system variables, viz., adsorbent dosage, initial dye concentration, pH and contact time were studied. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly. Higher adsorption percentages were observed at lower concentrations of methylene blue. Optimum pH value for dye adsorption was determined as 7.0 for both the adsorbents. Maximum dye was sequestered within 30 min after the beginning for every experiment. The adsorption of methylene blue followed a first order rate equation and fit the Lagergren equation well. Similar experiments were carried out with commercially available activated carbon to compare the results. Sulphuric acid treated sawdust or formaldehyde treated sawdust of Indian Rosewood can be attractive options for dye removal from dilute industrial effluents.

Biosorption of Cr (VI) from aqueous solution by Rhizopus nigricans

The study was aimed to quantify the Cr sorption ability of powdered biomass of Rhizopus nigricans at the best operating conditions. The influence of solution pH, agitation, Cr (VI) concentration, biomass dosage, contact time, biomass particle size and temperature were studied. The optimum pH for biosorption of Cr (VI) was found to be 2.0. Higher adsorption percentage was noted at lower initial concentrations of Cr ions, while the adsorption capacity of the biomass increased with increasing concentration of ions. Optimum biomass dosage was observed as 0.5% (w/v). More than 75% of the ions were removed within 30 min of contact and maximum removal was obtained after 8 h. Biomass particles of smaller size (90 μm) gave maximum adsorption (99.2%) at 100 mg/l concentration. The adsorption capacity increased with increase in temperature and agitation speed and the optimum were determined as 45°C at 120 rpm. Freundlich and Langmuir isotherms were used to evaluate the data and the regression constants were derived. The adsorption rate constant values ( K ad) were calculated for different initial concentration of Cr ions and the sorption was found to be higher at lower concentration (100 mg/l) of metal ion.