Solution pH Conditions Research Articles

Liquid Droplet of Protein-Polyelectrolyte Complex for High-Concentration Formulations

The formulation of high-concentration protein solutions is a challenging issue for achieving subcutaneous administration. Previously, we developed a method of precipitation-redissolution using polyelectrolyte as a precipitant to produce protein solutions at high concentrations. However, the redissolution yield of proteins was insufficient. This study aims to optimize the solution conditions for practical applications by combining IgG and poly-l-(glutamic acid) (polyE). A systematic analysis of solution pH and polyE size conditions revealed that an acidic condition favors precipitation, whereas neutral pH values are more effective for the redissolution. We find that the optimal size for polyE ranged from 15,000 to 50,000. This slight modification in the procedure in comparison with previous studies increased the precipitation and redissolution yields to nearly 100%, without irreversible protein denaturation. The fully reversible IgG-polyE complex formed as a droplet structure, which is similar to a condensate of liquid-liquid phase separation. The droplet structure plays an indispensable role in the salt-induced, redissolved state, which is pertinent to the new application that takes advantage of the methods to produce highly concentrated protein solutions.

Effect of ultrasound pre-treatment on adsorbent in dye adsorption compared with ultrasound simultaneous adsorption

Ultrasound was applied simultaneously with adsorption process in most of the previous studies. However, this method is not practical to treat huge amounts of coloured wastewater effluent. In this study, the efficiency of ultrasound pre-treated peanut husk powder at different power levels (1.5–3.5 W) in dye adsorption with several conditions of initial dye concentration (20–100 mg/L), contact time (0.5–5 h), solution pH (2–8), and dosage (0.1–0.3 g) was studied and compared with ultrasound simultaneous adsorption process and the control. Adsorption efficiency of indirect ultrasound pre-treated peanut husk powder has increased 25.78%, 13.64% and 1.5% compared with the control, ultrasound simultaneous adsorption and direct ultrasound pre-treated sample respectively at 60 mg/L of initial dye concentration. Indirect ultrasound pre-treated sample at 3.5 W has achieved the highest adsorption efficiency of 89.96% at solution pH 8 and 94.83% at 0.3 g dose for 3 h. The surface feature and textural properties of samples were characterized by using scanning electron microscopy and surface characterization analyser. The result indicated that more porous structure was created on the ultrasound pre-treated sample at increasing power levels.

Effects of Environmental Factors on the Synergy of Functional Bacteria in Completely Autotrophic Granular Sludge

To obtain experimental evidences for optimizing a completely autotrophic nitrogen removal process based on granules, the effects of dissolved oxygen (DO) concentration, temperature (t), initial ammonium (NH4+-N) concentration, and solution pH conditions on the synergy between the aerobic and anaerobic ammonium-oxidizing bacteria (AOB and AMX) were investigated using a single factor batch experiment, while the analysis of the microbial community structure within them was conducted using MiSeq high-throughput pyrosequencing. Results revealed that AOB (genus Nitrosomonas) and AMX (genus Candidatus Kuenenia) dominated in the granules, representing relative abundances of 32.9% and 9.8%, respectively. For the granules, the highest specific nitrogen removal rate of q(TN)=(17.7±1.0) mg·(g·h)-1 was obtained at a DO concentration of 2 mg·L-1, while the initial NH4+-N concentration was set at 100 mg·L-1. And a lower DO level resulted in partial nitritation became the rate-limiting step of process, otherwise, it would be the ANAMMOX reaction instead. According to the free energy of the reactions, the activity of AMX was more sensitive to low temperature than that of AOB. When the reaction temperature was lower than 30℃, nitrite accumulation could be observed in bulk liquid, with the significant decrease of q(TN) for the granules. Under the same oxygen supply conditions, an initial NH4+-N concentration lower than 100 mg·L-1 could inhibit the activity of AMX partly. However, with an initial NH4+-N concentration over 150 mg·L-1, either oxygen-limiting or high free ammonia concentration could lead to the dramatic decrease of q(TN). In addition, the effective synergy of the two types of ammonium oxidizers in granules was always achieved at solution pH in the range of 7.0-8.5.

Electrospun UiO-66/polyacrylonitrile nanofibers as efficient sorbent for pipette tip solid phase extraction of phytohormones in vegetable samples

In this work, metal-organic framework particles incorporated fibers (UiO-66/PAN nanofibers) were used as adsorbent in pipette tip solid phase extraction (PT-SPE) for the first time. The UiO-66/PAN nanofibers were fabricated by a facile electrospinning method and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption experiments. The UiO-66/PAN nanofibers were applied to assemble a novel PT-SPE cartridge for determination of four phytohormones followed by high performance liquid chromatography (HPLC). Several experimental parameters such as kinds of UiO-66/PAN nanofibers, the amount of UiO-66/PAN nanofibers, the effect of solution pH, ionic strength and desorption conditions were intensively investigated. Under the optimal conditions, the linear ranges of the phytohormones were in the range of 0.06–60 ng/mL with correlation coefficients above 0.992. The limits of detection were between 0.01 ng/mL to 0.02 ng/mL. The interday and intraday precision (RSD) for three replicate extractions of the four phytohormones (15 ng/mL for each) was in the range of 1.5–5.6%. The established method was successfully applied for the determination of phytohormones in watermelon and mung bean sprouts samples. The results showed that the electrostatic interaction between the positively charged UiO-66 and anionic forms of phytohormones played an important role in the extraction of the phytohormones.

Improved Accuracy for Constant pH-REMD Simulations through Modification of Carboxylate Effective Radii.

The accuracy of computational models for simulating biomolecules under specific solution pH conditions is critical for properly representing the effect of pH in biological processes. Constant pH (CpH) simulations involving implicit solvent using the AMBER software often incorrectly estimate pKa values of aspartate and glutamate residues due to large effective radii stemming from the presence of dummy protons. These inaccuracies stem from problems in the sampled ensembles of titratable residues that can influence other observable pH-dependent behavior, such as conformational change. We investigate new radii assignments for atoms in titratable residues with carboxylate groups to mitigate the systematic overestimation in the current method. We find that decreased carboxylate radii correspond with increased agreement with experimentally derived pKa values for residues in hen egg-white lysozyme and Δ+PHS variants of staphylococcal nuclease (SNase) and improved conformation state sampling compared to experimentally described expectations of native-like structure. Our CpH simulations suggest that decreasing the effective radii of these carboxylate groups is essential for eliminating a significant source of systematic error that hurts the accuracy of both conformational and protonation state sampling with implicit solvent.

Application of Fe3O4/RGO Nanocomposite as a Sorbent of Pesticides

In the present study, to extract the residue of seven pesticides (diazinon, chlorpyrifos, ethion, permethrine, cypermethrin, fenvalerate RR and fenvalerate SS) from raisin samples, reduced graphene oxide—Fe3O4 magnetic nanocomposite is applied as an adsorbent and then the preconcentrated pesticides were determined by GC–MS. The application of high adsorption capacity magnetic graphene oxide sheets in pesticides solid phase extraction, provides a fast and easy procedure without filtration or centrifugation. The extraction conditions were optimized by analyzing spiked raisin samples (80 ng mL−1). The parameters affecting the performance of the extraction such as nanoparticles concentration, extraction time, solution pH and desorption conditions were investigated using a univariate optimization process. The maximum adsorption was observed within 15 min at pH 7–8 using 0.4 mg mL−1 of adsorbent with the sample ionic strength of 0.02 M NaCl. Limits of detection and quantification were about 14 and 40 µg kg−1, respectively, for all of pesticides. The validated method was successfully applied for the determination of pesticides in raisin samples.

Protein-RNA complexation driven by the charge regulation mechanism

Electrostatic interactions play a pivotal role in many (bio)molecular association processes. The molecular organization and function in biological systems are largely determined by these interactions from pure Coulombic contributions to more peculiar mesoscopic forces due to ion-ion correlation and proton fluctuations. The latter is a general electrostatic mechanism that gives attraction particularly at low electrolyte concentrations. This charge regulation mechanism due to titrating amino acid and nucleotides residues is discussed here in a purely electrostatic framework. By means of constant-pH Monte Carlo simulations based on a fast coarse-grained titration proton scheme, a new computer molecular model was devised to study protein–RNA interactions. The complexation between the RNA silencing suppressor p19 viral protein and the 19-bp small interfering RNA was investigated at different solution pH and salt conditions. The outcomes illustrate the importance of the charge regulation mechanism that enhances the association between these macromolecules in a similar way as observed for other protein-polyelectrolyte systems typically found in colloidal science. Due to the highly negative charge of RNA, the effect is more pronounced in this system as predicted by the Kirkwood-Shumaker theory. Our results contribute to the general physico-chemical understanding of macromolecular complexation and shed light on the extensive role of RNA in the cell's life.

Retention and transport of graphene oxide in water-saturated limestone media

In this work, column experiments were conducted to investigate the transport characteristics of graphene oxide (GO) nanoparticles in limestone media under various electrolytes, solution pH, and humic acid (HA) concentration conditions. In the limestone media, GO exhibited relatively low mobility with the mass recovery rate lower than 65.2%, even when solution ionic strength was low. The presence of HA enhanced its mobility. In addition, the presence of S2-, a divalent anion, also promoted GO transport in limestone media compared to Cl− under similar ionic strength conditions through neutralizing more positive charge and thus diminishing the cation bridging. Solution pH showed slight effect on the transport of GO in limestone with the mass recovery range from 40.3% to 51.7%. Over all, decreases in solution pH, HA concentration and increases in solution ionic strength reduced the mobility of GO in the limestone media under the tested conditions. These results indicated both environmental conditions and media characteristics played important roles in controlling GO fate and transport in porous media. The one-site kinetic deposition model was applied to describe the interactions between the GO and limestone media and model simulations fitted the observed experimental data very well. As limestone is an important component of aquiferous media in subsurface, findings from this study elucidated the key factors and processes controlling the fate of GO particles in limestone media, which can inform the prediction and assessment of the risks of GO in groundwater environment.

Studies on electrochemical deposition and physicochemical properties of nanocrystalline Ni‐Mo alloys

Nanocystalline Ni‐Mo coatings were deposited from citrate-ammonia solution, in a model system with a rotating disc electrode (RDE) using low carbon steel discs as the cathode. The effect of parameters such as electrolyte solution pH (from 4 to 10), temperature (from 20°C to 60°C), and hydrodynamic conditions (RDE speed in the range of 0 to 640rpm) on chemical and phase composition, microstructure, average crystallite size of coatings and current efficiency of electrodeposition was investigated. It was confirmed that, in the induced co-deposition process, molybdenum acts as a grain refinement modifier. This, apart from influencing changes in surface morphology, has a significant effect on the mechanical properties of the layers. For alloys containing less than 16wt% of Mo (related to the crystallite size of 7nm) loss of strengthening effect (the inverse Hall-Petch relationship) was observed, which was correlated with the decrease in coatings' resistance to wear. Hence, for electrodeposition nanocrystalline Ni‐Mo alloys characterised by high microhardness, good resistance to wear and adhesion to the steel substrate, the suitable conditions for electrolysis were determined. These conditions include: electrolyte solution pH above 7, plating temperature in the range of 20°C to 40°C, and hydrodynamic conditions corresponding to the RDE speed of 260 to 640rpm.

Br-PADAP embedded in cellulose acetate electrospun nanofibers: Colorimetric sensor strips for visual uranyl recognition

In this work, a new visual colorimetric strip based on cellulose acetate nanofiber mats modified by 2-(5-Bromo-2-pyridylazo)-5-(diethylamino) phenol was successfully prepared via electrospinning technology. The prepared colorimetric strip showed high sensitivity towards UO22+ with the yellow-to-purple color change signal. Upon the optimal conditions of solution pH at 6.0 and response time for 80min, the detection limit for UO22+ can reach 50 ppb. Moreover, the strip also exhibited excellent anti-interference ability in the presence of other metal ions. In order to achieve the quantitative detection for UO22+, a color-differentiation map was established, which was prepared from converted H values. Finally, the strip was also used to detect UO22+ in the seawater and showed high sensitivity.

Transition from disordered aggregates to ordered lattices: kinetic control of the assembly of a computationally designed peptide.

Natural biomolecular self-assembly typically occurs under a narrow range of solution conditions, and the design of sequences that can form prescribed structures under a range of such conditions would be valuable in the bottom-up assembly of predetermined nanostructures. We present a computationally designed peptide that robustly self-assembles into regular arrays under a wide range of solution pH and temperature conditions. Controling the solution conditions provides the opportunity to exploit a simple and reproducible approach for altering the pathway of peptide solution self-assembly. The computationally designed peptide forms a homotetrameric coiled-coil bundle that further self-assembles into 2-D plate structures with well-defined inter-bundle symmetry. Herein, we present how modulation of solution conditions, such as pH and temperature, can be used to control the kinetics of the inter-bundle assembly and manipulate the final morphology. Changes in solution pH primarily influence the inter-bundle assembly by affecting the charged state of ionizable residues on the bundle exterior while leaving the homotetrameric coiled-coil structure intact. At low pH, repulsive interactions prevent 2-D lattice nanostructure formation. Near the estimated isoelectric point of the peptide, bundle aggregation is rapid and yields disordered products, which subsequently transform into ordered nanostructures over days to weeks. At elevated temperatures (T = 40 °C or 50 °C), the formation of disordered, kinetically-trapped products largely can be eliminated, allowing the system to quickly assemble into plate-like nanostructured lattices. Moreover, subtle changes in pH and in the peptide charge state have a significant influence on the thickness of formed plates and on the hierarchical manner in which plates fuse into larger material structures with observable grain boundaries. These findings confirm the ability to finely tune the peptide assembly process to achieve a range of engineered structures with one simple 29-residue peptide building block.

Effect of ball milling process on the structure of local clay and its adsorption performance for Ni(II) removal

The effect of ball milling process on the properties of the natural local clay including structural changes and adsorption capacity for the removal of Ni(II) ions from aqueous solutions, was investigated. The local clay was ground at varying times from 5 to 20h with a 10:1 or 20:1 weight ratio of the balls to powder, which produced six different ball milled clays (BM-Clay1 to BM-Clay6). Ground clays were then characterized by particle size measurement, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy analysis, and adsorption experiments. These analyses were performed to evaluate the changes in particle size distribution, morphology, crystallinity, and adsorption characteristics. According to XRD analysis, the degree of amorphization increased with grinding time, and the present crystalline phase in the final ball milled clay was found to be quartz, which was the associated phase in the original unmilled clay mineral. FTIR studies indicated the destruction of the layers of the montmorillonite upon milling. Adsorption experiments revealed that under similar conditions, BM-Clay2 has the most adsorption capacity for Ni(II) ions. Adsorption characteristics of this ball milled clay for the removal of Ni(II) ions from aqueous solutions was examined in batch adsorption studies under different conditions of contact time, solution pH, adsorbent dose, and initial Ni(II) concentration. The Langmuir maximum adsorption capacity was found to be 29.76mg/g at pH7 and 25°C. The adsorption kinetics data showed better agreement with the pseudo second-order kinetic model. Also, both surface adsorption and intra-particle diffusion contributed to the rate limiting steps in the adsorption of Ni(II) on clay adsorbent. In conclusion, grinding of local clay using ball milling process can significantly increase the adsorption capacity of the clay for Ni(II) removal from aqueous solutions.

The Degradation Chemistry of Farglitazar and Elucidation of the Oxidative Degradation Mechanisms

The chemical degradation of farglitazar (1) was investigated using a series of controlled stress testing experiments. Farglitazar drug substance was stressed under acidic, natural pH, basic, and oxidative conditions in solution. In the solid state, the drug substance was stressed with heat, high humidity, and light. Farglitazar was found to be most labile toward oxidative stress. A series of mechanistic experiments are described in which the use of 18O-labelled oxygen demonstrated that oxidative degradation of farglitazar is caused primarily by singlet oxygen formed under thermal conditions. Major degradation products were isolated and fully characterized. Mechanisms for the formation of degradation products are proposed. Drug product tablets were also stressed in the solid state with heat, high humidity, and light. Stressed tablets afforded many of the same degradation products observed during drug substance stress testing, with oxidation again being the predominant degradation pathway. Evidence for the activity of singlet oxygen, formed during thermal stress testing of the solid oral dosage form, is presented. The degradation pathways observed during stress testing matched those observed during long-term stability trials of the drug product.

Sorption of vanadium (V) onto natural soil colloids under various solution pH and ionic strength conditions

Batch sorption kinetics and isothermal characteristics of V(V) were investigated on three natural soil colloids (manual loessial soil colloid (MSC), aeolian sandy soil colloid (ASC), and cultivated loessial soil colloid (CSC)) under various solution pH and ionic strength (IS) conditions. Colloids were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). AFM micrographs showed CSC with an aggregated shape with larger particle diameter as compared with ASC and MSC. XRD spectra revealed the presence of different minerals in natural soil colloids including biotite, kaolinite, calcite and quartz, which might contribute to sorption process. The sorption ability decreased with increase of colloidal particle size. The sorption was mainly attributed to complexation by active carboxylate and alcohol groups of colloidal components. Sorption kinetics and isotherms of V(V) onto natural soil colloids were best fitted with Pseudo-second-order and Freundlich models. Langmuir model indicated that sorption capacity of MSC and ASC was comparable (285.7 and 238.1 mg g−1); however, CSC exhibited the lowest sorption capacity (41.5 mg g−1) due to its larger particle diameter and aggregated shape. The maximum V(V) sorption capacity reached plateau values at a solution pH ranged between 5.0 and 9.0 for MSC and ASC, and 6.0–8.0 for CSC. Sorption capacity of V(V) onto natural soil colloids decreased with increasing IS. Based on result of this study we can conclude that sorption of V(V) onto natural soil colloids is pH- and IS-dependent. These findings provide insights on the remediation of vanadium-contaminated soils.

Removal of hexavalent chromium from aqueous solutions by adsorption on modified groundnut hull

There is an emerging serious threat to the environment from indiscriminate release of heavy metals into the wastewaters and soil from human industrial practices. In this study therefore, the uptake of hexavalent chromium, being among the major pollutants from our industries, by modified and unmodified groundnut hull was investigated. The effects of different conditions of contact time, adsorbate concentration, solution pH, and temperature on sorption process were studied. The adsorbent materials were characterized by Fourier Transform Infrared Spectroscopy (FT-IR). Analysis of the surface morphology by Scanning Electron Microscopy (SEM) revealed a change in morphology upon chromium adsorption. The adsorption process of Cr(VI) ions onto both the unmodified groundnut hull (UGS) and the modified groundnut hull (MGS) is in good agreement with the Langmuir adsorption isotherm and follows the pseudo-second-order kinetic model. According to the equilibrium studies, chromium(VI) ions are better adsorbed by modified groundnut hull.

Removal of Cd (II) from water using the waste of jatropha fruit (Jatropha curcas L.)

The aim of this work was to evaluate the removal of Cd (II) from water using three biosorbents originated from the biomass of jatropha (bark, endosperm, and endosperm + tegument). For that, batch tests were performed to verify the effect of solution pH, adsorbent mass, contact time, initial concentration of Cd (II), and the temperature of the process. The adsorption process was evaluated by the studies of kinetics, isotherms, and thermodynamics. The ideal conditions of solution pH were 5.5 and 8 g L−1 of adsorbent mass of biosorbents by solution volume, with an equilibrium time of 60 min. According to the Langmuir model, the maximum adsorption capacity for bark, endosperm, and bark + endosperm of jatropha was, respectively, 29.665, 19.562, and 34.674 mg g−1, predominating chemisorption in monolayers. The biosorbents presented potential for the remediation of waters contaminated with Cd (II).

Formulation and physiochemical study of α-tocopherol based oil in water nanoemulsion stabilized with non toxic, biodegradable surfactant: Sodium stearoyl lactate

The unique properties such as high optical clarity, stability and enhanced bioavailability of nanoemulsion make them useful for food, cosmetic and pharmaceutical industries. In this work, sodium stearoyl lactate and Tween 80 surfactants were collectively used to fabricate alpha tocopherol based oil in water nanoemulsion using high energy ultrasonication method. The spherical nature of pure and drug loaded nanoemulsion has been confirmed with transmission electron microscopy (TEM). The influence of pH, dilution, surfactant concentration and ionic strength on average particle size of pure and nutraceutical (benzylisothiocyanate and curcumin) encapsulated emulsion was examined. The prepared emulsion exhibited good stability up to 90days in salt solution (50–200mM) and different pH conditions. The cumulative release % of benzylisothiocyanate and curcumin was found to be 50.29% in 36h and 89.15% in 150h respectively. The antioxidant activity of pure, benzylisothiocyanate, curcumin and cocktail (benzylisothiocyanate and curcumin) nanoemulsion was calculated with 2,2-diphenyl-1-picrylhydrazyl radical. The IC50 value of different antioxidant showed that benzylisothiocyanate nanoemulsion acted as better antioxidant as compared to pure and curcumin encapsulated nanoemulsion. Also the cell viability of pure nanoemulsion was found to be 24% on hep G2 cell. The effect of UV light irradiation on curcumin and benzylisothiocyanate stability was carried out in different solvent conditions (water/ethanol and nanoemulsion). The degradation of curcumin by the impact of UV light was successfully controlled by trapping in NEm.

Role of sodium hexametaphosphate in MgO/SiO2 cement pastes

The extent of reaction between magnesium oxide (MgO) and silica fume (SiO2) is normally limited and mixes require high water contents to give suitable rheology. The use of considerably lower water contents and the formation of magnesium silicate hydrate (M-S-H) gel as a binding phase is made possible by adding sodium hexametaphosphate (Na-HMP) to the mix water prior to the addition of MgO and SiO2. This results in the formation of extensive reaction products and cured samples with high compressive strength and low porosity. In this work, the effect of Na-HMP on the hydration of MgO/SiO2 mixes is investigated using high water to solids ratio samples to allow monitoring of pH and the solution chemistry during hydration. It is shown that a relatively small amount of Na-HMP inhibits the formation of Mg(OH)2 when MgO is hydrolyzed. It is proposed that this is due to adsorption of phosphate species on the MgO which inhibits the nucleation of the Mg(OH)2. This gives rise to high Mg2+ species in solution and elevated pH (>12) conditions relative to when Mg(OH)2 forms. In contrast, the phosphate does not suppress formation of M-S-H gel. In combination with the enhanced dissolution rate of SiO2 at high pH, M-S-H gel can form quickly without competition for Mg2+ ions by Mg(OH)2 precipitation. Incorporating the optimum concentration of Na-HMP into the mix water therefore transforms the properties of cement paste and mortar samples formed by reacting MgO and SiO2.

Immobilization of lead and copper in aqueous solution and soil using hydroxyapatite derived from flue gas desulphurization gypsum

Flue gas desulphurization (FGD) gypsum is an abundant waste generated from coal-fired power plants. This study evaluated the potential application of hydroxyapatite (F-HAP) derived from FGD gypsum for immobilization of lead (Pb) and copper (Cu) in water and soil. MINTEQ software was employed to determine the species distribution of Pb(II) and Cu(II) at different solution pH conditions. The factors that affect sorption behavior such as pH effect, sorption kinetics, thermodynamics, and isotherms were investigated using batch tests. Various kinetics and isotherms models were used to fit the obtained data. The experimental results showed that the amount of Pb(II) and Cu(II) adsorbed on F-HAP increased as the pH increased from 2.0 to 6.0, and adsorption was enhanced with the rise in temperature. The predicted maximum adsorption capacities were found to be 1.376 and 0.460mmol/g for Pb(II) and Cu(II), respectively. The values of mean free energy (E) obtained from Dubinin-Radushkevich (D-R) model implied that the chemical reaction, which was stronger than ion exchange governed the process of Pb(II) adsorption, while the adsorption of Cu(II) was mainly ascribed to ion exchange. XRD analysis revealed that the final solid obtained after Pb(II) immobilization was mainly mixed of pyromorphite and F-HAP, while the final solid acquired after Cu(II) immobilization still consisted of a single phase of F-HAP. On the other hand, application of F-HAP in contaminated soil effectively reduced the leachable and exchangeable Pb and Cu, reflecting that F-HAP is a potential material for remediating environmental pollution with Pb and Cu. This study realized the potential of a modified geochemical waste material towards remediation of metal contaminated soils, providing very useful and valuable information for other similar solid wastes, such as paper sludge and phosphogypsum.

Adsorption of methylene blue using modified adsorbents from drinking water treatment sludge.

This study aims to explore the preparation and application of alum sludge (AS) and mud sludge (MS) from a drinking water treatment plant to remove methylene blue (MB) dye from aqueous solution. The sludge (MS and AS) was treated by chemical and physical activation to obtain new adsorbents. The adsorption experiments were carried out under different conditions of initial dye concentration (50-100 mg/L) adsorbent dosage (0.05-0.25 g), solution pH (3-9), temperature (20-60 °C) and contact time (20-90 min). Scanning electron microscopy (SEM) and X-ray diffraction instruments were used for characterization of the developed adsorbents. The results show that sludge activated by nitric acid (0.25 M HNO3) and pyrolysis at 700 °C were the best chemically and physically activated adsorbents. The optimum adsorption conditions for the adsorption of MB are 100 ppm initial dye concentration, 1 hour contact time, 250 °C solution temperature, pH 7 and 0.25 g adsorbent dosage. Application of the Langmuir and Freundlich Isotherm models showed that adsorbents fitted the Langmuir model well. SEM studies indicated the porous structural aspects of sludge suitable for removing MB dye.