Cited by (24)
Boron removal by means of adsorption processes with magnesium oxide - Modelization and mechanism
2009, Desalination
The boron adsorption process, in borate ion form, onto magnesium oxide was described in terms of mathematical equations and, taking into account the knowledge acquired by means of experimental data, the most probable mechanism of boron removal process was proposed. The modelization has been carried out by establishing Langmuir adsorption isotherms and kinetic law. Upward convex curves are observed indicating that the process is advantageous towards boron adsorption. Moreover, the adjustment of experimental data to their corresponding functions leads to highly satisfactory correlations for all the studied conditions and pseudo-second-order kinetic model was observed. As for the mechanism of the adsorption process, a superficial process of chemosorption comprising three stages or reactions is proposed: 1) the hydration reaction of magnesium oxide as it is in contact with the aqueous solution to yield a magnesium hydroxide gel over the surface of which the active points for adsorption are located, 2) the alkalisation reaction of the solution due to the acid–base reaction between magnesium oxide and water and 3) the stereospecific chemical reaction between borate ions and active centres. This mechanism develops with time to reach stabilisation and leads to the formation of an adsorption monomolecular layer that is typical in chemosorption processes, as well as in systems following Langmuir adsorption isotherms and pseudo-second-order kinetics.
Boron removal by adsorption onto activated alumina and by reverse osmosis
2008, Desalination
The presence of boron compounds in waters increases in a continuous and parallel way to industrial development. Therefore, their harmful effects on living organisms also increase, especially on plants, since this element manifests an important micronutrient-toxic boron duality.
The aim of this study is to investigate the boron removal by the adsorption process onto activated alumina and by membrane processes.
Boron removal from aqueous solutions was investigated using activated alumina. Experiments were conducted to delineate the effect of stirring time, pH, adsorbent dose and boron concentration. Effects of foreign ions such as sulfate, fluoride, nitrate, hydrogenocarbonate and silica on boron removal by adsorption onto activated alumina were studied.
The content of boron in water can be also reduced by means of various membrane processes. The reverse osmosis tests were carried out with the use of Osmonics spiral module equipped with AG 2514 TF membrane. Using conventional RO, significant removal of boron has been observed only in its ionic form. Experiments were conducted to present membrane retention as a function of pH and to delineate membrane performance.
Boron removal by means of adsorption with magnesium oxide
2006, Separation and Purification Technology
(Video) Ion Exchange resinsThe presence of boron compounds in waters increases in a continuous and parallel way to industrial development. Therefore, their harmful effects on living organisms also increases, especially on plants, since this element manifests an important micronutrient–toxic boron duality. The aim of this study is to investigate the influence of different operation variables within the adsorption process of the boron compounds with magnesium oxide when liquid waste of urban, agricultural or industrial origin is being treated. The results obtained indicate that the process is strongly influenced by the quality of added reagent and by the contact time between the reagent and solution. Moreover, the temperature variable also stands out, as it has a very positive influence, reducing the necessary contact time to obtain specific boron removal yields. On the one hand, it has been observed that this process appears to be inextricably linked to pH. The removal process improves as the pH increases, presenting a maximum at pH value between 9.5 and 10.5, which is where borate ion predominates. The reagent used in the study has an important alkalinising capacity. Due to the fact that the pH of the solutions is situated around this range, it is not necessary to adjust this variable during the process. Therefore, using this reagent is an attractive option. As for the metallic cations that usually accompany boron in industrial waste, it seems that the reagent's presence also facilitates the removal of these cations and a simultaneous treatment of industrial waste can thus be carried out. Furthermore, interrelationships between the different variables have been established. When the optimum conditions are selected, the process reaches over 95% of boron removal.
Boric acid as a mobile phase additive for high performance liquid chromatography separation of ribose, arabinose and ribulose
2006, Journal of Chromatography A
A new high performance liquid chromatographic (HPLC) method is described for the analysis of ribose, arabinose and ribulose mixtures obtained from (bio)chemical isomerization processes. These processes gain importance since the molecules can be used for the synthesis of antiviral therapeutics. The HPLC method uses boric acid as a mobile phase additive to enhance the separation on an Aminex HPX-87K column. By complexing with boric acid, the carbohydrates become negatively charged, thus elute faster from the column by means of ion exlusion and are separated because the complexation capacity with boric acid differs from one carbohydrate to another. Excellent separation between ribose, ribulose and arabinose was achieved with concentrations between 0.1 and 10gL−1 of discrete sugar.
Boron removal from industrial wastewaters by ion exchange: An analytical control parameter
2005, Desalination
The results obtained from the application of molecular absorption spectrophotometry using Azomethine H to establish breakthrough curves for the boron purification process are presented in order to determine the breakthrough point, or maximum acceptable effluent concentration, which is regulated by environmental legislation. The breakthrough capacity of the ion-exchange process and the degree of column utilisation were also calculated. The results were highly satisfactory at the level of experimental work in the laboratory; however, although the method of the Azomethine H stands out for its simplicity and sensitivity, it is slow as a method for control of the exchange process and of regeneration in a pilot plant or an industrial plant. For the purpose of obtaining an in-line method, pH and specific conductivity of the aliquot of the effluent were determined. A sample for this was taken during the test of elution in the fixed bed of resin. The combined representation and the comparison of the values of boron concentration, pH and specific conductivity of the effluent showed that the pH cannot be adapted for a quick determination of the breakthrough point; however, the conductivity can. A conductivity sensor can be designed to quickly detect the moment that the breakthrough point is reached.
Adsorption of boron from boron-containing wastewaters by ion exchange in a continuous reactor
2005, Journal of Hazardous Materials
In this study, boron removal from boron-containing wastewaters prepared synthetically was investigated. The experiments in which Amberlite IRA 743, boron specific resin was used were carried out in a column reactor. The bed volume of resin, boron concentration, flow rate and temperature were selected as experimental parameters.
The experimental results showed that percent of boron removal increased with increasing amount of resin and with decreasing boron concentration in the solution. Boron removal decreased with increasing of flow rate and the effect of temperature on the percent of total boron removal increased the boron removal rate. As a result, it was seen that about 99% of boron in the wastewater could be removed at optimum conditions.
(Video) Ion Exchange Resins, Cation Exchange Resins, Anion Exchange Resins
Recommended articles (6)
Research article
Selective removal of arsenic(V) from natural water using N-methyl-d-glucamine functionalized poly(propylene) membranes
Journal of Environmental Chemical Engineering, Volume 2, Issue 4, 2014, pp. 2221-2228
Functionalized membranes for As(V) removal were synthesized by grafting glycidyl methacrylate in the fibrous and microporous host substrates, and subsequently reacting these precursor membranes with N-methyl-d-glucamine (NMDG). These membranes have been characterized and studied for As(V) removal from aqueous solution by the permeation method using dense membranes and flow-through method using fibrous membranes. In the permeation experiment, it was observed that As(V) could be transferred 60% from feed (ground water) to receiver compartment (NaOH) using the dense NMDG-membranes. The lower transfer of As(V) from feed to receiver compartment was due to counter transport of OH− ions from a receiver to a feed compartment. To address this problem, the removal of As(V) by sequential flow-through cycles of the feed and receiver across the fibrous NMDG-membrane was studied. In this mode, 92% of As(V) was sorbed in the fibrous NMDG-membrane in one cycle of 7.5min for 15mL feed. As(V) was deloaded to 66% by a single cycle of 0.3molL−1 NaOH. The HPLC method was also developed for quantifying As(V) content preconcentrated in a receiver solution. This method could be used for coupling desorption flow through cycle directly to the HPLC system. The reusability experiments showed that the membranes developed in the present work is highly stable and can be regenerated without affecting their As(V) removal efficiency.
Research article
A combined experimental and theoretical study on supramolecular assemblies in octahedral cobalt(III) salicylaldimine complexes having pendant side arms
Polyhedron, Volume 112, 2016, pp. 86-95
(Video) Ion exchange chromatographyTwo mononuclear cobalt(III) complexes, [Co(L1)(N3)2(deen)] (1) and [Co(L2)(N3)2(DMSO)] (2), where HL1 {2-(2-(diethylamino)ethyliminomethyl)-4-bromophenol} and HL2 {2-(2-(diethylamino)ethyliminomethyl)-6-methoxyphenol} are tridentate and tetradentate Schiff bases, respectively and deen is a bidentate chelating ligand, N,N-diethyl-1,2-diaminoethane, were prepared and characterized by elemental and spectral analysis. X-ray crystal structure determination confirmed their structures. Both complexes are meridional isomers. The solid state structures show the participation of the organic ligands in concurrent conventional and unconventional C
H⋯π interactions along with hydrogen bonding. The energetic features of these interactions have also been studied by means of DFT calculations.Research article
High resolution analysis of the (111) vibrational state of SO2
Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 144, 2014, pp. 1-10
The high resolution Fourier transform spectrum of the weak band was recorded and analyzed for the first time. 1085 transitions with values of quantum numbers and were assigned to that band. The hot band was also recorded and analyzed, and 1132 transitions with values of quantum numbers and were assigned. On the basis of the obtained information, 780 ro-vibrational energies of the (111) upper vibrational state were determined. The derived results significantly exceed analogous results known in the literature both in number of the assigned transitions and upper energy levels, and in values of quantum numbers and .
Research article
Effects of Pressure in Cathodic Deposition of TiO2 and SnO2 with Supercritical CO2 Emulsified Electrolyte
Electrochimica Acta, Volume 208, 2016, pp. 244-250
This study reports the effect of the high pressure on properties, especially the crystallinity, of the TiO2 and SnO2 films cathodically deposited in supercritical CO2 emulsified electrolyte. The as-deposited metal oxides are usually amorphous when cathodic deposition is applied. An additional heat treatment process is needed to have crystalline metal oxides. In this study, the TiO2 and SnO2 thin films cathodically deposited at elevated pressure showed an improvement in the crystallinity with an increase in the pressure using X-ray diffraction analysis. The high-resolution transmission electron microscopy and selected-area electron diffraction confirmed that the TiO2 deposited at 35MPa had the anatase crystal structure. An enhancement in the charge carrier dynamics at the TiO2 electrode/electrolyte interface with an increase in the pressure was observed from the electrochemical impedance spectroscopy, which is a result of the improved crystallinity. The effect of the pressure on the crystallinity of the SnO2 was more obvious than that on the TiO2. Grain size of the SnO2 films estimated by the Scherrer equation was increased from 3.5 to 14.8nm when the pressure was increased from 5 to 25MPa.
(Video) Ion Exchange Resins Know HowResearch article
Selective separation of chloride and sulfate by nanofiltration for high saline wastewater recycling
Separation and Purification Technology, Volume 166, 2016, pp. 135-141
In order to effectively separate chloride (such as NaCl) and sulfate (such as Na2SO4) for high saline wastewater recycling, one commercial NF membrane (named Desal-DL) was employed in the permeation of the single and binary salt solutions of NaCl and Na2SO4 with a lab-scale cross-flow batch module, where the salt concentration ranged from 4 to 96gL−1 and the operating pressures varied from 0.6 to 2.4MPa as well as the temperature was kept under room temperature. The experimental results showed that the Desal-DL NF membrane had a low rejection to NaCl and a high rejection to Na2SO4 for single salt solutions. While for binary salt solutions, the membrane presented a bit higher rejection to SO42− and much lower rejection to Cl−, even special negative rejection to Cl− was observed when the concentration of Na2SO4 was high. This implies that NF is suitable to be used for the separation of Na2SO4 and NaCl from their binary solution, where Na2SO4 could be retained by the NF membrane and concentrated to high concentration while NaCl could pass through the membrane and might be diluted to low concentration with a diafiltration operation mode. Finally the selective separation of Na2SO4 and NaCl by NF diafiltration was simulated for the binary salt solution containing 23.4gL−1 NaCl and 8.76gL−1 Na2SO4. A highly concentrated solution of Na2SO4 (71.74gL−1) and a relatively pure solution of NaCl (20.79gL−1) were obtained, which favored the post-treatment of high saline wastewater for inorganic salts recycling.
Research article
Arsenic(V) removal using an amine-doped acrylic ion exchange fiber: Kinetic, equilibrium, and regeneration studies
Journal of Hazardous Materials, Volume 325, 2017, pp. 223-229
This study investigates As(V) removal from aqueous solutions using a novel amine-doped acrylic ion exchange fiber. The amine doping reaction was confirmed using FT-IR, and the surface of the fiber was characterized using FEG-SEM. The synthesis process was completed within 60min using an AlCl3·6H2O catalyst at 100°C, and the resulting in a fiber with an ion exchange capacity of 7.5meq/g. The removal efficiency of the A-60 fiber was affected by the solution pH, and the efficiency was optimum at pH 3.04. As(V) adsorption on the fiber was rapid in the first 20min and reached equilibrium in 60min. As(V) removal followed pseudo-first-order kinetics, and the Redlich-Peterson adsorption isotherm model provided the best fit of the equilibrium data. The fiber has an As(V) adsorption capacity (qe) of 205.32±3.57mg/g, which is considerably higher than literature values and commercial adsorbents. The removal efficiency of the fiber was above 83% of the initial value after nine regeneration cycles.
H⋯π interactions along with hydrogen bonding. The energetic features of these interactions have also been studied by means of DFT calculations.Copyright © 1993 Published by Elsevier Ltd.
FAQs
What is strong base anion exchange resin? ›
The strongly basic anion exchange resin is an anion exchange resin with quaternary ammonium groups incorporated into the styrene frame. Two types with differing alkalinity strengths are: Type I with a trimethyl ammonium group, and Type II with a dimethylethanol ammonium group.
What is the use of anion exchange resin? ›Ion-exchange resins are insoluble polymers containing a backbone of cross-linked polystyrene and side chains of ion-active groups. The ion-exchange resins are widely used for prevention of drugs from binding to the surface of the tongue and the oral cavity and suppression of drugs' unpleasant tastes.
What is the color of anion resin? ›Strong-base gel anion resin is almost always light amber in color when new.
What is an example of anion exchange resin? ›These resins also bind to anionic drugs in the intestine and decrease their absorption and their therapeutic effects. Examples are warfarin, thyroxine, digitalis, propranolol, and thiazides.
What is the difference between strong base and weak base anion exchange resin? ›Compared with strong base anion (SBA) exchange resins, WBA resins are easier to regenerate and can be efficiently regenerated with a small amount of NaOH. In addition, WBA resins have greater capacities for mineral acids, better chemical stability and stronger resistance to organic fouling than SBA resins.
What are characteristics of anion exchange resins? ›Anion exchange resins consist of a polymeric matrix to which different functional groups are attached. Most weakly basic anion exchangers contain tertiary amino groups; in a few cases primary and secondary groups are also encountered.
What does anion resin remove? ›Cation and anion resins remove dissolved ionic contaminants.
Does anion resin remove nitrates? ›Anion resin in the chloride form removes not only nitrates, but also sulfate and alkalinity.
Does anion resin lower pH? ›Anion resin will remove alkalinity and the pH will be suppressed during the service cycle. pH adjustment may be required.
What is the difference between Type 1 and Type 2 anion resin? ›There are two chemicals that generally are used for the amination step, each producing a different type of SBA resin with different chemical properties. Type I SBA resins are aminated with trimethylamine. Type II SBA resins, developed after the SBA Type I, are aminated with dimethyl-ethanolamine.
What is the shelf life of anion resin? ›
Generally, ion exchange (IX) resins may be safely stored for two to five years (or longer) without significant chemical or physical deterioration.
Is anion resin positive or negative? ›Anion resins and cation resins are the two most common resins used in the ion exchange process. The difference between anion and cation resins is that one is positively charged (anion) and the other is negatively charged (cation).
What does anion exchange bind? ›Anion exchange resins will bind to negatively charged molecules, displacing the counter-ion. Anion exchange chromatography is commonly used to purify proteins, amino acids, sugars/carbohydrates and other acidic substances with a negative charge at higher pH levels.
Which functional group is present in anion exchange resin? ›The functional groups are sulfonic (–SO3H), carboxylic (–COOH), or phosphonic (–PO32 −) acids for resins capable of exchanging cations, whereas anion exchange resins possess basic functional groups, such as quaternary ammonium or ammine groups (Korkisch, 1989).
What does anion exchange resins removes from the hard water? ›In the Ion Exchange Resin method, resins are used, which can completely remove the cations and anions present in the hard water. The resins used are generally organic, cross-linked and insoluble polymers with some functional groups responsible for the ion-exchange properties.
What are the important characteristics of a good ion exchanger? ›- Resin Specification Explanation. This section covers several important topics regarding the characteristics of ion exchange resin. ...
- Total Capacity. ...
- Salt Splitting. ...
- Moisture Level. ...
- Macroporosity. ...
- Microporosity. ...
- Particle Size. ...
- Uniformity of Particle Size.
Weak base anions are more chemically stable than strong base anions and are used for the removal of mineral acids, organic acids and other organic materials. They are highly resistant to organic fouling. Purolite.com uses cookies to give you the best possible experience.
What is the difference between cationic and anionic resin? ›The main difference between cation and anion resins is that one is positively charged (cation) and the other is negatively charged (anion). This makes them useful in removing different types of contaminants (which will also vary depending on their size and chemical composition).
What is the difference between cation exchange resin and anion exchange resin? ›Anion resins and cation resins are the two most common resins used in the ion-exchange process. While anion resins attract negatively charged ions, cation resins attract positively charged ions.
What are the factors affecting anion exchange chromatography? ›The factors that affect separation during ion exchange chromatography include the surface area of the stationary phase (resin bead size); the density of exchange sites on the stationary phase surface (cross-linkage); the flow rate of the mobile phase (resin bead size and column geometry; system pressure in high- ...
Which solution is regenerated in anion exchanger resins? ›
The anion exchange resins are generally regenerated with sodium hydroxide (48% w/v rayon grade in lye form (as per IS: 252) solution of suitable strength.
Does anion resin remove fluoride? ›Anion exchange
Low concentrations of fluoride ions can be removed by ion exchange using a strong base anion resin.
Chelating resins are used to collect trace metals from seawater. Further, a copper-loaded chelating resin also adsorbs, by coordination, traces of amino acids from seawater.
What is the best resin for nitrate removal? ›Betapet Nitrapore is a Macroporous Nitrate Removal Resin. Nitrates has always been an issue for the hobby and fishkeepers and now there is a cost effective way of keeping them down. Nitrapore is best used as a filter media in your Aquarium, Fish Tank or Pond.
What is the best filtration to remove nitrates? ›Reverse Osmosis is our number one recommendation for treating nitrates in your drinking water. Reverse Osmosis will effectively remove up to 95% of nitrates in your water depending on your original water temperature, quality and system pressure.
What neutralizes nitrates in fish tank? ›Removal is simple enough if you carry out large, regular water exchange. Water changes are a sure shot, as they instantly and permanently remove the nitrate from the system. Want to remove 20 percent of the nitrate in the water? Do a 20 percent water change; it's as straightforward as that.
Do anions affect alkalinity? ›Alkalinity in most natural waters is due to the presence of carbonate (CO3=), bicarbonate (HCO3-), and hydroxyl (OH-) anions. However, borates, phosphates, silicates, and other bases also contribute to alkalinity if present.
What are the disadvantages of anion exchange chromatography? ›One of the main disadvantages of ion exchange chromatography is its buffer requirement: because binding to IEX resins is dependent on electrostatic interactions between proteins of interest and the stationary phase, IEX columns must be loaded in low-salt buffers.
What elutes first in anion exchange chromatography? ›A compound with a lower charge will elute first. The stationary phase would have charges opposite those of the ions that we wished to separate. For example, maybe the column is packed with a phase that contains many anions.
What does A and B mean in resin? ›All of their retail formulas are two-part epoxy systems made up of a resin (Part A) and a hardener (Part B). As with all epoxy resins, our systems are designed to work in a specific mix ratio between the two parts. Our CLR epoxy resin with CLF Fast Hardener works in a 100:47 mix ratio by weight or a 2:1 volume ratio.
What pH is weak anion exchange resin? ›
WBA (weakly basic anion exchange) resins can be usually used in a pH range from 0 to 9.
What are the three 3 types of commonly used resin? ›There are three widely used resin types: polyester, vinyl ester, and epoxy.
What is the temperature limit for anion resin? ›The limits of thermal stability are imposed by the strength of the carbon-nitrogen bond in the case of anion resins. This strength is sensitive to pH and low pH enhances stability. A temperature limitation of 60°C (140°F) is recommended for hydroxide cycle operations.
Can unused resin go bad? ›Those who have used polyester resins know that its shelf life is only about six months before it turns to a useless jelly-like substance. An abundance of expired material can easily cancel the initial cost savings of cheaper materials.
How do you recharge anion resin? ›Resin is regenerated on site using hydrochloric or sulfuric acid and sodium hydroxide (caustic) to regenerate the cation and anion respectively.
What is Type II strong base anion resin? ›Aldex SB-2 is a strongly basic, Type 2, gel anion resin. It provides superior regeneration efficiency and greater resistance to organic fouling than Type 1 strongly basic exchangers. Aldex SB-2 is intended for use in all types of dealkalization deionization and chemical processing applications.
How do you store anion resin? ›Storage of Used Resins Resins should be stored in their original unopened packaging in a cool dry area. An indoor storage facility with climate control between 0-30° C (32-90° F) should be used for the best results.
How do you clean anion resin? ›Ensure anion resins are fully exhausted as peracetic acid performs best at a pH < 8. Make up 1 bed volume (BV) of peracetic acid solution containing 0.1% peracetic acid. Inject 1 BV of disinfectant at a flow rate of 5 BV/h (0.6 USGM/ft3) with displacement discharged to a drain approved for chemical waste disposal.
What is anion absorption? ›Anion adsorption involves an electrostatic interaction and some chemical interaction between the surface and the ion. The Langmuir model is incomplete in describing this adsorption because it takes no account of charge.
What binds to an anion exchange column? ›Negatively charged glycans such as sialic acids bind to the anion exchanger, while neutral sugars pass through the column.
What is the anion exchange capacity? ›
Anion exchange capacity (AEC) represents the positive charge available to attract anions in solution. In most soils CEC > AEC. Figure 3. Ion exchange between nutrient sources (minerals and OM) and plant roots.
What is an example of a weak anion exchange resin? ›For example, TOYOPEARL SuperQ-650 resin (pKa about 12.2) is functionalized with a quaternary amine which is considered a strong base. Hence it is called a strong anion exchange resin. However, TOYOPEARL DEAE-650 is functionalized with a putative weak basic group and is called a weak anion exchange resin.
What functional groups are strong anion exchange? ›PHENOLS | Solid-Phase Extraction
The typical functional groups of strong or weak basic anion exchangers are –CH2–N+(CH)3 and – N + H ( R ) 2 − respectively.
Ion exchange resins are used to soften water by replacing the cations with sodium ions (and possibly the anions with chloride ions) of sodium chloride. They may also be used to demineralize water where the cations are replaced by H+ ions and the anions are replaced by OH− ions.
How is cation and anion exchange process used for the treatment of hard water? ›Cation exchange water softeners remove the calcium and magnesium ions found in hard water by exchanging them with sodium (or potassium) ions. Once all the ions are fully exchanged, the water softener undergoes a regeneration process to flush the system of excess ions and recharge with new sodium ions.
How do you regenerate the exhausted cation and anion exchange resin? ›The exhausted cation exchange resin can be regenerated by the moderately concentrated sodium hydroxide solution.
What is strong base anion resin water treatment? ›Strong base anion resins (SBA), operated in the chloride form, can remove many contaminants from drinking water. These contaminants include arsenic V (also known as arsenate), nitrate, chromate, fluoride and uranium.
What is the difference between a strong and weak ion exchanger? ›A “weak” exchanger is ionized over only a limited pH range, while a “strong” exchanger shows no variation in ion exchange capacity with changes in pH.
What is the difference between Type 1 and Type 2 strong base anion resin? ›Type I resins are the most thermally stable followed by Type II with acrylics being the least temperature resistant. All the SBA resins are more susceptible to temperature degradation in the hydroxide form than in the chloride form.
How do you know which anion is the stronger base? ›When comparing the stability of the conjugate base, look at the atoms which have the negative charge and compare their relative electronegativities. The greater the electronegativity of the atom, the greater the hold on the electrons. As a result, this leads to a more stable anion.
What are the advantages and disadvantages of ion exchange process? ›
Specific advantages and disadvantages
This enables effective selectivity. It also enables particular heavy metals to be re-used. Ion exchangers are quickly polluted, which considerably reduces the exchange capacity.
Household water softeners are ion exchange devices. Ion exchange involves removing the hardness ions calcium and magnesium and replacing them with non-hardness ions, typically sodium supplied by dissolved sodium chloride salt, or brine.
How does flow rate affect ion exchange? ›Flowrate is one of the major determining variables in sizing a water softener. Ion exchange is not instantaneous. The faster water passes through resin, the more resin it must pass through to become soft. The depth of the resin band required to soften water is the reaction zone.
What resin sets the hardest? ›Tough-Cast 65D is a two part casting resin that is virtually indestructible. It's designed to make durable prototypes, and reproductions. Tough-Cast 65D is a two component polyurethane casting resin that is virtually indestructible.
Does stronger base mean the more stable base? ›Weaker bases have negative charges on more electronegative atoms; stronger bases have negative charges on less electronegative atoms. Thus, the methoxide anion is the most stable (lowest energy, least basic) of the three conjugate bases, and the ethyl carbanion anion is the least stable (highest energy, most basic).
Which anion A or B is the stronger base? ›Answer and Explanation: Compound B is a stronger base.
Why are anions more reactive? ›Anions, with their excess of electrons, tend to be more reactive and have a higher tendency to gain or share electrons with other atoms to achieve a stable electron configuration.