Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries

Our plain-English summary of Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries, by A. Pourjavadi, S.M. Fakoorpoor, S.H. Hosseini (Carbohydrate Polymers, 2013).

The study

• Authors: A. Pourjavadi, S.M. Fakoorpoor, S.H. Hosseini
• Journal: Carbohydrate Polymers
• Published: 2013;93(2):506-11
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A new cationic flocculant was synthesized by graft copolymerization of acrylamide (AM) and 3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) onto salep using free radical polymerization initiated by ammonium persulfate (APS) to produce cationic salep [S-g-P(AM-co-MAPTAC)]. Reaction parameters (monomers/salep ratio, concentration of reactants, MAPTAC/AM ratio, and APS) were optimized using a full factorial experimental design to obtain the highest settling rate for cement suspensions. The best performing product was characterized by gel permeation chromatography (GPC), FTIR, (1)H NMR spectroscopy, and thermogravimetric analysis (TGA). The resulted cationic flocculant may be introduced as a promising candidate for the green production of asbestos-free fiber cement products by Hatschek process.

Copyright © 2012 Elsevier Ltd. All rights reserved.

In plain English

This was a laboratory chemistry study, not a study of asbestos exposure or health. It reports no data on asbestos or on people. The authors, at Sharif University of Technology in Tehran, Iran, made a new positively charged (cationic) flocculant, a substance that clumps fine particles so they settle. They made it by grafting acrylamide and a cationic monomer, MAPTAC, onto salep, a polysaccharide from orchid tubers. Using a full factorial experimental design, they made a series of versions, numbered 156 to 171 in the article's table, and measured how fast each made Portland cement suspensions settle. In a 6 wt.% cement slurry, the best-performing version, sample 170, gave settling rates of 9.1 mm/s at 10 ppm and 12.5 mm/s at 50 ppm. Native (unmodified) salep gave 0.5 mm/s at both doses. Neutral and anionic versions did not form flocs and acted as dispersants. The authors concluded that the new flocculant was more efficient and easier to prepare than other cationic flocculants and could be used in the Hatschek process to make asbestos-free fiber cement products. They noted that comparison with other flocculants was not easy or straightforward.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory synthesis and testing study (polymer chemistry) using a two-level full factorial experimental design
• Who was studied: No human or animal subjects. The study tested suspensions of Tehran Portland Cement Type I in water. These were treated with cationic salep flocculant formulations numbered 156 to 171 in Table 1, and with neutral, anionic and native salep comparison samples. The work was done at Sharif University of Technology, Tehran, Iran. The article does not give dates for the experiments.
• Exposure: No asbestos or human exposure was studied. The tested material was a salep-based graft copolymer flocculant, salep-g-P(AM-co-MAPTAC), added to cement suspensions, mainly at 10 ppm and 50 ppm. Settling rate was the measure of performance.
• Main results:
  • The best-performing formulation, sample 170, gave settling rates of 9.1 mm/s at 10 ppm and 12.5 mm/s at 50 ppm of flocculant, measured on a 6 wt.% cement in water slurry.
  • Native salep gave settling rates of 0.5 mm/s at both 10 ppm and 50 ppm in the same test.
  • The neutral and anionic graft copolymers made from the best formulation did not form flocs. They reduced the settling rate compared with cement slurry without flocculant, acting as dispersants.
  • The two most important synthesis parameters for settling rate, at both flocculant concentrations, were the weight ratio of total monomers to salep and the salep/water percentage.
  • The weight average molecular weight of the best flocculant (3.13 × 10^6) was nearly twice that of native salep (1.64 × 10^6).
  • By titration, 97% of the cationic monomer was grafted, corresponding to a cationic charge density of 0.564 meq/g in the optimum sample.
  • Thermogravimetric analysis showed higher thermal stability for the cationic salep than for native salep.
• The authors' conclusion: The authors concluded that the new salep-g-P(AM-co-MAPTAC) was more efficient and easier to prepare than other cationic flocculants. They concluded it could be used in the Hatschek process to produce eco-friendly fiber-cement products, in which asbestos is replaced by cellulose fibers.
• Limitations the authors state:
  • The authors stated that comparing this flocculant with other flocculants for cement suspensions is not easy or straightforward, because studies use different techniques, instruments and conditions.
  • The authors' conclusion that their flocculant needs a lower dose than others rests on an assumption: that the highest settling rates in their work correspond to the best flocculation conditions reported in other studies.

Topics

Medical terms in this study, explained in our Lexicon: Thermogravimetric Analysis.

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