Rheological study of partially hydrolyzed polyacrylamide-hexamine-pyrocatechol gel system

Abstract

Removal of metals from wastewaters causes a big concern from the environmental point of view due to their extreme toxicity towards aquatic life and humans. Application of As(III) from aqueous solution by ZnO nanorods as adsorbent has been investigated in the present study. The synthesized nanorods were characterized by XRD, FT-IR spectroscopy, SEM, and thermogravimetric analysis. Optimum biosorption conditions were determined with respect to pH, adsorbent dose, contact time, and temperature. The experimental data were examined using the Lagergren's first-order, pseudo-second-order and intraparticle diffusion kinetic models. The results revealed that the pseudo-second-order kinetic model provided the best description of the data. Langmuir and Freundlich isotherm models were applied to the equilibrium data. The maximum As(III) sorption capacity of ZnO nanorods was found to be 52.63 mg/g at pH 7, adsorbent dose 0.4 g, contact time 105 min, and temperature 323 K. The calculated thermodynamic parameters, ΔG o (between − 5.741, − 5.342 and − 4.538 kJ/mol at 303-323 K), ∆H o (13.75 kJ/mol) and ∆S o (0.0616 J/mol K) showed that the sorption of As(III) onto ZnO nanorods was feasible, spontaneous and exothermic, respectively.

Synthesis, characterization and evaluation of polyacrylamide graft starch/clay nanocomposite hydrogel system for enhanced oil recovery

“…Polymer gels are widely used to control water production by blocking the high-permeability zones in heterogeneous mature reservoirs and then diverting the water to the low-permeability zones during enhanced oil recovery operations. Polymer gel is very cost-effective as it does not require a work over rig and it can control water production for a long period of time Bai 2012, 2016;Yadav and Mahto 2013b;Zhao et al 2011). Synthetic polymers and biopolymers are two main types of polymers which have been used in reservoirs since the 1950s.…”

Hydrogels Applied for Conformance-Improvement Treatment of Oil Reservoirs

“…Gelling systems based on polyacrylamide cross-linked with hydroquinone (HQ), hexamethylenetetramine (HMTA), and sodium bicarbonate-formed hydrogels that remained stable for 12 months, at 149°C, and for 5 months, at 176.7°C [52,53]. This nontoxic biopolymer gels in the absence of cross-linker when the pH value is reduced below 10.8.…”

“…The screening and selection of the most appropriate gelling polymer system for the conformance-improvement treatment of an oil reservoir can be done using different laboratory tests (i.e. bottle tests, continuous and oscillatory rheological measures, and core flooding experimental tests) to access information on the gelation time and final gel strength, as well as the short-and long-term stability of gelling polymer systems under specific reservoir conditions − temperature, salinity, pH value of the formation water, and the presence of either carbon dioxide (CO 2 ) or hydrogen sulfide (H 2 S) [20,35,53,[80][81][82][83].…”

Study of the polymer concentration and polymer/crosslinker ratio effect on gelation time of a novel grafted polymer gel for water shutoff using a central composite design method

“…Therefore, there is a vital need to reduce excessive water production from oil and gas wells for the petroleum industry. [4][5][6] The gel polymer treatment is one of the most efficient chemical methods to control of excess water production in chemically enhanced oil recovery. [7][8][9] The most widely used gelant system is the aqueous solution of partially hydrolyzed polyacrylamide as polymer and Cr(III) acetate as crosslinker.…”