8 results about "Cross linked chitosan" patented technology

The invention discloses a stainless steel pickling waste liquid treatment method, and relates to the technical field of pickling waste liquid treatment.The stainless steel pickling waste liquid treatment method comprises the steps that quaternized iminodiacetic acid functionalized cross-linked chitosan aerogel is prepared, an adsorption column is filled with the quaternized iminodiacetic acid functionalized cross-linked chitosan aerogel, the stainless steel pickling waste liquid is pumped into the adsorption column, and selective adsorption operation is conducted; ni and Cr in the waste liquid are selectively chelated by iminodiacetic acid groups, and F is captured by quaternary ammonium salt groups; when it is monitored that the concentration of Ni or Cr at the outlet end of the adsorption column reaches a preset value, it is regarded that adsorption is saturated, feeding is stopped, and stepwise elution and resource recovery are conducted in sequence; and washing the adsorption column with deionized water until the pH value of an outlet is neutral to complete material regeneration for the next round of adsorption circulation. According to the method, nickel and chromium can be selectively recycled from the strong acid waste liquid, fluorine is synchronously captured, hazardous waste sludge is not produced, the used materials are stable, durable and recyclable, the problems of resource waste and secondary pollution are solved, and recycling and harmless treatment of the waste liquid is achieved.

The invention discloses a multilayer crystal coated controlled-release nitrogen fertilizer based on root system organic acid triggering and a preparation method thereof, and belongs to the technical field of controlled-release fertilizers. The fertilizer is a multi-layer controlled-release nitrogen fertilizer formed by sequentially coating a Zn-Mg phosphate crystal layer, a PLGA temperature-sensitive layer and a Ca / Fe cross-linked chitosan-succinic acid trigger layer with urea or urea formaldehyde particles as a core. The crystal layer in the fertilizer provides 90-120 d baseline slow release, the temperature-sensitive layer is subjected to peak clipping, the outermost layer disintegrates under the action of rhizosphere organic acid, micropores are exposed, and on-demand nitrogen supply is achieved. Field tests show that compared with common urea, the nitrogen utilization rate of the fertilizer is increased by about 50%, nitrogen leaching loss and ammonia volatilization are reduced by about 60%, the yield is remarkably increased, and the technical effect is remarkable.

The present invention relates to the field of water treatment, and particularly relates to a cross-linked chitosan and its preparation and application. The cross-linked chitosan is obtained by cross-linking N -ethyl chitosan with glutaraldehyde. The advantages of the present invention are that the reaction process is simple, the conditions are mild, the reaction materials are cheap and easily available, and it is easy to promote industrial application. The amino cross-linked chitosan has a fast adsorption rate and a large adsorption capacity for phenoxycarboxylic acid compounds in water. Moreover, the amino cross-linked chitosan can be recycled, enhancing the adsorption performance of chitosan and expanding the application scope of chitosan. It can be applied to the fields of water treatment and pollutant adsorption. Formula (1) N -ethyl chitosan and glutaraldehyde are cross-linked. The advantages of the present invention are that the reaction process is simple, the conditions are mild, the reaction materials are cheap and easily available, and it is easy to promote industrial application. The amino cross-linked chitosan has a fast adsorption rate and a large adsorption capacity for phenoxycarboxylic acid compounds in water. Moreover, the amino cross-linked chitosan can be recycled, enhancing the adsorption performance of chitosan and expanding the application scope of chitosan. It can be applied to the fields of water treatment and pollutant adsorption. Formula (1)

The present invention relates to a novel cross-linked chitosan and formulations, compositions and uses thereof. In particular, the present invention relates to nanoparticles useful as active agents and delivery systems for at least one biologically active agent and compositions thereof.

The present invention belongs to the field of environmental functional materials and relates to a preparation method of a cross-linked chitosan nanosponge adsorbent for efficiently removing cationic and anionic dyes. The specific steps are as follows: Dissolve chitosan powder in a 0.5-2% dilute acetic acid solution; Add a 2-5% glutaraldehyde solution according to a volume ratio of 1:(10-20) to the chitosan solution and stir for 0.5-1 h for cross-linking; After the nanosponge fully absorbs the chitosan solution, place it in a refrigerator at 4°C for cross-linking for 4-6 h; Immerse the sponge block in a NaOH solution, allow it to react fully for 5-10 s, and then let it stand at room temperature for 24 h to age the chitosan on the sponge fibers; Wash with ultrapure water until neutral and then dry at a low temperature of 40°C to obtain a cross-linked chitosan nanosponge composite adsorbent. The cross-linked chitosan nanosponge adsorbent prepared by the present invention has excellent removal ability for cationic and anionic dyes in wastewater, and has the advantages of strong acid and alkali resistance, low cost, large adsorption capacity, reusable multiple times, simple and rapid separation, and the dye can be desorbed and recovered, etc., and has good application prospects in the field of wastewater treatment.

The present application provides a modified oxygen-releasing nano-peroxide for degrading organic pollutants, a preparation method therefor and a use thereof, and a composite slow-release oxygen material, a preparation method therefor and a use thereof. The modified oxygen-releasing nano-peroxide comprises an oxygen-releasing nano-peroxide, a pH regulator, a polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer, and a cross-linked chitosan membrane layer. The polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer encapsulates the oxygen-releasing nano-peroxide and the pH regulator, and the cross-linked chitosan membrane layer encapsulates the polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer. The modified oxygen-releasing nano-peroxide has high purity and good dispersibility, can maintain stable dissolved oxygen content in water for a relatively long time, and has minimal impact on the environmental pH.

In various aspects, the present invention relates to methods of treating or preventing bleeding of a tissue site comprising applying a chitosan powder composition to a tissue site. In various aspects, the present invention relates to a chitosan powder composition for application to a tissue site, where the powder composition comprises a chitosan salt, a crosslinked chitosan, a derivatized chitosan, or a combination thereof. In various aspects, the invention relates to a catheter assembly preloaded with a chitosan powder composition and configured to deliver the chitosan powder composition to a tissue site.

The present invention discloses a method for regulating and recovering a sewage treatment system after a shock. The method comprises: when the fluctuation amplitude of the respiratory rate is less than 10% of the lower limit of the normal range for more than 60 minutes, an alarm is notified to the control system, water intake is stopped, and powdered activated carbon and a biosorbent are added to the system. The alarm is released when the respiratory rate returns to the normal range, and the addition of activated carbon is first stopped. When the effluent ammonia nitrogen concentration is lower than the emission standard limit, the addition of the biosorbent is stopped and water intake is restarted to continue operation. The system achieves rapid recovery after the shock and enters a stable operating state. The biosorbent is based on cross-linked chitosan embedded with calcium carbonate, on which heterotrophic bacteria are adsorbed and grown, wherein the heterotrophic bacteria account for 5% to 50% of the mass of the adsorbent. The method of the present invention can achieve early warning and timely eliminate the risk of shock. It does not require re-acclimation and cultivation of sludge, reduces recovery time, and ensures long-term stable operation of the system.