Effect of the Resorcinol/Formaldehyde Ratio and the Temperature of the Resorcinol–Formaldehyde Gel Solidification on the Chemical Stability and Sorption Characteristics of Ion-Exchange Resins

Abstract

A series of resorcinol–formaldehyde resins (RFR) samples for Cs-137 removal from liquid alkaline media have been synthesized. It has been demonstrated that the chemical stability as well as sorption characteristics are determined by the resorcinol/formaldehyde molar ratio and the solidification temperature. It has been also demonstrated that the sample synthesized at the resorcinol/formaldehyde molar ratio of 1.8/2.2 and solidified at 210 °C is characterized by the best sorption-selective characteristics and chemical stability. Under dynamic conditions, at feeding >1000 bed volumes of a model solution with pH > 13, the RFR 3-1 goes through six sorption cycles without noticeable changes in the sorption characteristics. The results are presented that demonstrate the possibility of RFR application in the decontamination of real LRW from Cs-137.

Gelling Behavior of PAM/Phenolic Crosslinked Gel and Its Profile Control in a Low-Temperature and High-Salinity Reservoir

“…The crosslinking reactions of PHRO gel are condensation reactions between polyacrylamide (PAM), hexamethylenetetramine (HMTA) and resorcinol (RO). There are three types of crosslinking reactions [ 17 ]: HMTA is hydrolyzed to produce formaldehyde, which is crosslinked with PAM; Formaldehyde reacts with RO to generate polyhydroxy methyl phenol, which is crosslinked with PAM; Formaldehyde reacts with RO to phenolic resin, which is crosslinked with PAM. …”

“…The crosslinking reactions of PHRO gel are condensation reactions between polyacrylamide (PAM), hexamethylenetetramine (HMTA) and resorcinol (RO). There are three types of crosslinking reactions [17]:…”

“…Gelation agents are water-soluble polymers, such as polyacrylamide and polyethylene imine, of which polyacrylamide and its derivatives are the most commonly used. For crosslinking agents, there are two main types [ 14 , 15 , 16 , 17 ]: (1) organic metal crosslinking agents, such as Cr 3+ , Zr 4+ and Al 3+ , can be crosslinked with the carboxylic acid group in the polymer molecule; (2) organic crosslinking agents, such as formaldehyde-phenol and phenolic resin, can be crosslinked with amide groups in polymer molecules. At present, research on gel focuses on middle and deep reservoirs, whereas there are few studies on shallow reservoirs with low temperature and high salinity.…”

Removal of Cs-137 Radionuclide by Resorcinol–Formaldehyde Ion-Exchange Resins from Solutions Simulating Real Liquid Radioactive Waste

“…The values of the distribution coefficients of Cs-137 in LRW alkaline simulates (NaNO 3 -2.25 mol/L, NaOH-0.75 mol/L) obtained using these materials were above 10 3 mL/g. In addition, we demonstrated earlier that the RFR stability and selectivity to Cs in alkaline solutions can be improved via the optimization of the synthesis parameters [23]. It was shown that the increase of the resorcinol/formaldehyde molar ratio in the reagent mixture from 0.6/2.2 to 1.8/2.2 and the gel solidification temperature from 130 • C to 210 • C yielded a stronger polymer network with an increased accessibility of adsorption sites.…”

High-Temperature-Resistant Epoxy Resin Gel Behavior and Profile Control in Heavy Oil Steam Drive

“…Upon stabilization of the strength code, the current code reflected the strength level of the EHRB, and the corresponding gelation time was documented. Each group had three parallel samples, and the gelation time was the average of the sample data [35,36].…”