Saturated solution of sodium lignosulfonate relationship between the concentration of hydrochloric acid concentration, Figure 2. Sodium lignosulphonate solubility in strong acidic medium, small and nearly constant (HCl ≥ 1mol /
A saturated solution of sodium lignosulfonate lignin content of the vertical axis to a pH of abscissa plotted in Figure 1. Solubility of lignosulfonate closely with the media. In strong acidic medium, the poor solubility (pH = 0.1, solubility of less than 0.2g / L); thereafter, with increasing pH, solubility increases rapidly, and when the pH is above 5, the solubility with pH changes and leveled (pH = 6.1, the solubility of 204g / L).
Lignin sulfonate medium at different pH values solubility
The use of spectrophotometry at 25 ℃ ligosulfonate at different pH medium solubility. The results show that the strong acid solution, its solubility is very small and almost constant, and in the neutral or alkaline medium, the concentration of the saturated solution 200g / L or so.
Sodium lignosulphonate from kraft pulp cooking method or extracted from waste paper can also be obtained through the lignosulphonate [1,2]. It is in the industrial, agricultural, petrochemical, construction and other aspects of a broad and important use [3,4], both good surface active agents, dyes and pesticides dispersant, is also an important chemical raw material. Studies show that the pH value is very significant impact on the physical and chemical properties of lignin sulfonate, such as solubility, surface activity, foaming, foam stability and the stability of various lignosulfonate. Solubility is a very important and common physical properties
Lignosulfonate solubility and pH value of the relationship
Goals for the future development of carbon fiber is applied so that more low-cost producers in the car . From the Federal University of Rio de Janeiro, Brazil (Federal University of Rio De Janeiro) professor Kawei Du (Calvado) states: If the United States uses 13 kg per car carbon fiber, then the current global carbon fiber production have failed to meet the supply. He also pointed out that the cost of carbon fiber is required to meet the conditions of 10 U.S. dollars per kilogram , the ideal goal is $ 5 per kilogram , the intensity of at least 1.72Gpa, modulus of at least 170Gpa.
Oak Ridge National Laboratory under the U.S. Department of Energy , is one of America’s most important laboratory also developed the world’s first atomic bomb laboratory , carbon fiber Ministry has already set up a total investment of $ 40 million .
MOST carbon fiber back in March 2009 by the U.S. government and enterprises initiated the establishment of a total of 75 units , the purpose is to accelerate the production of carbon fibers bigger and cost reduction . November 2012 formally began the development of this year, on January 26 to make a success of the first batch of carbon fiber. Carbon fiber carbon fiber as an American National Science and Technology R & D and industrialization enterprise bridge , there are including the United States National Aeronautics and Space Administration (NASA), 3M, U.S. Hearst Corporation (Hexcel) and Ford , etc. 25 U.S. government agencies and enterprises, the current does not accept non-US business. Ministry of Science and director of the carbon fibers in a speech , pointed out that as a national asset servicing industry , carbon fiber Ministry ‘s mission is to help the industry breakthrough in low-cost difficulties and achieve a lot more technical production .
Oak Ridge National Laboratory experts spoke stressed with Lignin lignin as raw material to manufacture low-cost carbon fiber is the trend, because lignin is a renewable resource , and the original use of polyacrylonitrile -based carbon fibers are petroleum-based raw materials, as non- renewable resources. They are expected to do with lignin mesh carbon fiber costs can be controlled within 4 to $ 5 per kilogram .
Currently Oak Ridge National Laboratory has been used to replace the traditional polyacrylonitrile lignin production of carbon fiber, this year they raised short-term goal is to complete an annual output of 25 tons of low-cost carbon fiber.
Canada Ubc University professor Frank (Frank) R & D team is also developing lignin production of low-cost carbon fiber.
The company also revealed that the world’s major production of carbon fiber on the latest trends. In early April , the U.S. Dow Chemical (Dow) and Turkey Aqsa polyacrylonitrile staple fiber company (Aksa) together invest $ 1 billion joint venture : Advanced Composites DowAksa Holdings BV (DowAksa Advanced Composites Holding BV), about production plant in the United States and Russia . Dow Chemical and Ford are jointly developed low-cost, high- yield carbon fibers and carbon-carbon composite materials for applications in next-generation automotive industries.
Oak Ridge National Laboratory called carbon fiber production enterprise: carbon fiber as a work of art should be produced in order to produce the perfect product .
As a niche product viscose -based carbon fiber is now the United States has been basically shut down , and only a small production company . University of Tennessee is also developing .
Belong to the high-end niche and mesophase pitch -based carbon fiber in the aerospace and civilian fields and a large number of new applications, especially in systems that require high thermal conductivity materials and high modulus materials, so it has also become the highest price of all carbon fiber inside the product . Currently the United States only U.S. Cytec (Cytec) in the production , NASA is the largest customer .
As the production of carbon fiber equipment Hubble companies, but also demonstrate to the delegates of the latest production of carbon fiber production equipment and technology and other new and improved equipment .
Lignosulfonate is one of lignin derivatives. It is the source and lignin, chemical structures and physical properties are different. Lignosulfonate mainly from the sulfite pulping process resulting “black liquor”, separated from the black liquor extracted, mainly sodium lignosulphonate or calcium lignosulphonate.
The three components of wood lignin itself (the other two are the cellulose and hemicellulose), is a natural polymer, the content is generally in the plant cellulose> lignin> hemicellulose. Lignin extracted from plants and there are many ways, including organic solvent extraction, alkaline extraction, anthraquinone extraction. If lignosulphonate extraction, you will get a lignosulfonate.
Common lignin and lignosulfonate biggest difference is insoluble in water, easily soluble in water and lignosulfonate. Lignosulfonate very easy to absorb moisture in the air.
Microbial fuel cell (Microbial fuel cell, MFC) is a use of microorganisms as a catalyst in the organic chemical energy into electrical energy. MFC attached to the anode by microbial degradation of organic matter in electrons and protons, and the resulting electron transfer to the anode, the external circuit to the cathode, thereby generating outer current; protons generated directly or through the proton exchange membrane to the cathode, and the electron acceptor (oxygen, iron, potassium, etc.) reduction reaction occurs, the completion of the internal positive charge transfer. MFC has both organics and externally output power characteristics, as a new energy technologies attracting widespread attention. At present, has been shown by the microorganism of glucose as fuel, acetate, lactate, and other easily degradable substances and food processing waste, sewage and other organic waste, but the use of lignin sulfonate as the fuel degradation and production of MFC electricity has not been reported.
Lignin sulfonate is sulfite pulping and paper industry waste in the major pollutants. Lignin sulfonate waste separation and purification methods usually ultrafiltration method and the long-chain amine resin method, but low yield of only 30%. There are still a lot of waste lignin sulfonate, if direct emissions, it will cause damage to the ecological environment. For the treatment of lignin sulfonate are common thermochemical method, chemical oxidation method, but the former need to harsh conditions such as high temperature and pressure under which the metal oxide such as nitrobenzene oxidation Activity oxide are generally not suitable for industrial applications . The microbial fuel cell can be degraded under mild conditions while organic matter directly generate electricity. If the MFC in the production of electricity and can effectively degrade lignin sulfonate, low energy consumption compared to the pulp and paper effluent treatment provides new ideas and technology, which has great economic value.
Paper products Application lignosulfonate
China is the world ‘s paper-making powers , lignin sulfonate is sulfite pulp or fiber pulp production of major products , derived from renewable resources. Development and utilization of this abundant and cheap resources has important practical significance. Lignosulfonates phenylpropane derivatives by hydrophobic backbone and hydrophilic sulfonic acid groups and other groups composed of a relative molecular mass complex a wide range of polymers. Since lignin sulfonate molecules containing phenolic hydroxyl group , alcoholic hydroxyl group , a carboxyl group , a carbonyl group , a sulfonic acid functional groups . Carboxyl and sulfonic acid functional group is flocculation . A phenolic hydroxyl group , alcoholic hydroxyl group , a carbonyl group to a metal ion chelation , sulfonic acid group and a phenolic hydroxyl group can be adsorbed on the metal surface protective metal , phenol ether structure has a stable protective film.
In addition , lignin sulfonate also scattered with adsorption , adhesion , rheology and colloidal properties and other physicochemical properties of the surface , which is widely used in agriculture, industrial equipment maintenance , construction, oil industry , water treatment and other fields. In agricultural applications , fertilizer synergist in kraft pulping , the alkaline lignin degradation and the sulfurization reaction , but also a certain degree of condensation reaction, the phenolic hydroxyl group and a carboxyl group generated a certain chelating capacity . Sulfonated kraft lignin obtained by cation-exchange agent, chelating 5% Fe, Cu, Zn.
An acid pulping waste lignin lignin synthesis spherical cation exchange resin prepared directly carbonized resin water quality; carbonization conditions investigated, using electron microscopy, thermal gravimetric analysis, X-ray diffraction instrument for lignin carbonizing the resin structure, carbonation loss, pore structure, surface area and adsorption capacity and other properties were studied.
The results showed that: zinc chloride resin prepared by carbonizing spherical lignin optimal process conditions, carbonization time 0.5h, carbonization temperature 400 ℃, activation time 1h, activation temperature 500 ℃. Carbonization of the resin surface area 382.3m2 / g, the amount of methylene blue adsorption 132.6mg / g. Lignin carbonized resin spherical pore structure has a rich, good physical and chemical properties.
History The first generation superplasticizer – naphthyl superplasticizer and melamine resin-based superplasticizer was developed in the early 1960s out, due to performance than ordinary water reducer – to late 1930s hair lignosulfonate open represented – is obviously improved , which is also known as superplasticizers . The second generation superplasticizer is sulfamate , although chronologically is the third generation superplasticizer – polycarboxylate afterwards. The sulfonic acid groups have both a graft copolymer of a carboxylic acid group is the third generation of the most important superplasticizer , the performance is the best superplasticizer . Main types of superplasticizer water reducing rate of 20 % or more. Now mainly naphthalene , melamine , and by their compound from the reducing agent, which naphthalene , accounting for 67%. In particular, China is the most naphthalene superplasticizer are the main raw material of naphthalene superplasticizer . Naphthalene superplasticizer content according to their level of Na2SO4 products can be divided into high-concentration products (Na2SO4 content < 3% ) , medium thick products (Na2SO4 content of 3% to 10% ) and low enriched products (Na2SO4 content> 10% ) . Most naphthalene superplasticizer synthesis plant all have the Na2SO4 content is controlled below 3% of capacity , and some can even be advanced enterprises controlled below 0.4% .
To calcium lignosulfonate ( hereinafter referred to as wood calcium ) as the main raw material , the use of catalytic oxidation and lead compound modified method, developed a superplasticizer GCL. Determine the modified process conditions , the Fe2 + + Cu2 + induced catalyzed hydrogen peroxide as the oxidant , the amount of wood calcium 2% to 5 %, reaction temperature 90 ± 2 ℃, reaction time is 1 to 2 hours , the pH of 8 to 10 , the amount of wood modifier Ca 2 % to 5% . Experimental determination of the GCL for cement and concrete water-reducing performance enhancements .
The results showed that when the GCL dosage is 0.5 %, the grout water reduction of 20% , 3-28 days of concrete compressive strength increased by 50 % ~ 162% , reaching a standard of superplasticizer . GCL also has the advantages of small loss of fluidity , mixing cement paste the GCL placed 120 minutes fluidity loss of only 22 %, while the FDN superplasticizer fluidity under the same conditions , but the loss of 62% . GCL preliminary study of the surface properties , the results show that compared with calcium lignin sulfonate , GCL ‘s is significantly improved surface properties , the surface tension of the solution from the 4.6 × 102N / m decreased to 2.5 × 102N / m, and can form micelles , the critical micelle concentration of 1g / L, the improved dispersibility of cement particles , cement particles while increasing the amount adsorbed on the surface of 30% .