Sulfonated Naphthalene Formaldehyde Condensates Research Articles

Admixtures Used in Self-Compacting Concrete: A Review

Self-compacting concrete or self-consolidated concrete is a highly flowable, non-segregating concrete which spreads into congested reinforcement area and fills the formwork without the use of any vibrators. Self-compacting concrete allows denser reinforcement, optimized concrete section and shapes, and greater degree of freedom. It has the advantages of maintaining the durability and characteristics and meeting expected performance requirements. It has been used ideally in bridges, drilled shaft, and earth-retaining structure, columns and area with high concentration of rebars and pipes. The self-compacting concrete improves constructability, reduces skilled labor and noise level, minimizes the voids in highly reinforced area, gives superior strength and durability and smooth and uniform surface finishing and accelerates the project schedules. In the present study, various mineral admixtures, i.e., ground-granulated blast-furnace slag, limestone powder, silica fume, fly ash and chemical admixtures such as sulfonated melamine formaldehyde condensate, melamine formaldehyde, sulfonated naphthalene formaldehyde condensates and polycarboxylate ether-based superplasticizer, have been studied in the self-compacting concrete. A critical review of the effect of combination of these mineral and chemical admixtures on various rheological, strength and durability properties of the self-compacting concrete is presented in this paper.

A case of death after ingestion of an agrochemical spreading agent

An agrochemical spreading agent was found near the slightly decomposed corpse of a deceased female. The appearance of the stomach contents suggested that ingestion of a surfactant had occurred before death. The spreading agent was found to contain nonionic nonylphenol ethoxylates (NPEO(n)) and anionic sulfonated naphthalene-formaldehyde condensates (SNFC(n)). A solid phase extraction cartridge containing a mixed reversed phase-weak anion exchange sorbent (Oasis WAX, Waters) was used to successfully extract both NPEO(n) and SNFC(n) from the blood. The cartridge was preconditioned with methanol and acetic acid (AcOH). After the dilute blood sample was applied to the cartridge, it was washed with AcOH, and then NPEO(n) and SNFC(n) were eluted with methanol/dichloromethane (7:3, v/v) and 5% NH(3)/80% methanol, respectively. The concentrations of NPEO(n=2-9) and SNFC(n=0) in the blood sample were 7.7μg/mL and 1.8mg/mL, respectively. It is possible that postmortem changes increased the concentration of SNFC(n=0) monomer by breaking down the polymer. However, the behavior of these compounds in the human body is unclear and further case studies are needed to investigate this result.

The role of tannins in conventional and membrane treatment of tannery wastewater

The role that tannins play in tannery wastewater treatment has been evaluated employing a pilot Membrane Bioreactor (MBR) plant and a full scale Conventional Activated Sludge Process (CASP) plant conducted in parallel. The proposed methodology has established the preliminary use of respirometry to examine the biodegradability of a selection of commercial products (synthetic and natural tannins); the subsequent analysis, by means of spectrophotometric reading and RP-IPC (Reverse-Phase Ion-Pair) liquid chromatography, estimates the concentrations of natural tannins and naphthalenesulfonic tanning agents in the influent and effluent samples. The results show that a consistent percentage of the Total Organic Carbon (TOC) in the effluent of the biological phase of the plants is attributable to the presence of natural and synthetic (Sulfonated Naphthalene-Formaldehyde Condensates, SNFC) tannins (17% and 14% respectively). The titrimetric tests that were aimed at evaluating the levels of inhibition on the nitrifying biomass samples did not allow a direct inhibiting effect to be associated with the concentration levels of the tannin in the effluent. Nonetheless, the reduced specific growth rates of ammonium and nitrite oxidising bacteria imply that a strong environmental pressure is present, if not necessarily due to the concentration of tannins, due to the wastewater as a whole. The differences that have emerged by comparing the two technologies (CASP and MBR), in regards to the role that tannins play in terms of biodegradability, did not appear to be significant.

A water-soluble acrylate/sulfonate copolymer. I. Its synthesis and dispersing ability on cement

A new water-soluble methacrylate/2-acrylamido-2-methylpropane sulfonate copolymer (PMAMP) was synthesized and evaluated as a dispersion agent for cement particles. PMAMP was prepared from methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMP). The structure of the prepared polymer was verified by its NMR and IR spectra. The dispersing properties of PMAMP were evaluated by a minislump test on cement pastes. The test results indicated that this copolymer could disperse the cement particles and improve the minislump of cement pastes. Compared with a commercial superplasticizer (sulfonated naphthalene formaldehyde condensates), PMAMP performed better in enhancing the fluidity of the cement pastes. The polymer with about 40–50% AMP and a weight-average molecular weight of about 5 × 104 was most effective in dispersing cement particles and promoting the fluidity of cement pastes. Nevertheless, PMAMP with a higher AMP content or a higher molecular weight appeared to cause less slump loss. This was related to the interaction of this admixture with the cement particles and its adsorption behavior onto the cement particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2490–2496, 2006

Occurrence and Solid−Liquid Partition of Sulfonated Naphthalene−Formaldehyde Condensates in the Aquatic Environment

Sulfonated naphthalene-formaldehyde condensates (SNFC) are high production volume chemicals used in a variety of applications, for example, as concrete plasticizers, tanning agents, or dye dispersants. They enter the aquatic environment primarily by the wastewater path. The occurrence and fate of the monomers, which are different isomers of mono- and disulfonated naphthalene, was intensively investigated in previous studies. However, the environmental fate of the persistent higher molecular SNFC is so far widely unknown. This paper describes an ultrasonic extraction under alkaline conditions, followed by ion-pair HPLC with fluorescence detection for the analysis of SNFC oligomers from solid environmental matrixes such as sewage sludge, suspended solids, and river sediments. Limits of quantification of about 0.1 mg kg-1 d.m. were well below the measured concentrations in environmental samples. SNFC were adsorbed to suspended solids and river sediments in three major German rivers (Rhine, Neckar, and Danube) in concentrations typically up to several mg kg(-1) d.m. A total content of about 4 g kg(-1) d.m. was measured in a sewage sludge of a municipal wastewater treatment plant, which receives wastewater from a textile dyeing plant. Furthermore, the first quantitative field data on the partition of SNFC and their monomers between the aqueous phase and solid environmental compartments are presented. Solid-liquid partition coefficients (Kd) of oligomers with a chain-length ranging from three to six naphthalenesulfonate units were derived from the analysis of corresponding wastewater and sewage sludge samples and from suspended solids and river water samples, respectively. Determined Kd values were in the range from 10(2) to 10(4) L kg(-1).

Sorption and mass fluxes of sulfonated naphthalene formaldehyde condensates in aquifers

Sulfonated naphthalene formaldehyde condensates (SNFC) and their monomeric analogues were used as superplasticizers for cement suspension injections at two tunnel construction sites that are in direct contact with groundwater. Because in one case the aquifer is an important drinking water resource, the behavior of SNFC in the groundwater was carefully investigated. Chemical analyses showed that SNFC leached to the groundwater in concentrations of up to 58 μg/l of total SNFC at a distance of about 60 m down-gradient from the construction site. Of the individual SNFC components, only monomers and oligomers with up to four units could be detected in the groundwater. Oligomers with more than four units did not leach from the cement paste. The leached oligomers were transported in the groundwater at different velocities, which can be explained by sorption experiments. Mass fluxes of SNFC used at the tunnel construction sites were evaluated. Most SNFC were immobilized in the cement, but 5% (w/w) of the applied SNFC were found to leach into the aquifer. This corresponds to a total amount of leached SNFC of approximately 100 kg, of which about 80% are biodegraded in the aquifer and 20% (20 kg) still remain in the groundwater.

Occurrence of naphthalenesulfonates and their condensates with formaldehyde in a landfill leachate and their transport behavior in groundwater of the Upper Rhine Valley, Germany

Naphthalenesulfonates and their condensation products with formaldehyde are manufactured in the chemical industry for broad application as tanning agents, dispersing agents, and as superplasticizers for concrete. With the disposal of waste they have found their way into the aquatic environment. Five monomeric naphthalenesulfonates and a group of dimeric sulfonated naphthalene-formaldehyde condensates (SNFC) were identified in the leachate and in groundwater observation wells downstream in the plume of the Karlsruhe-West landfill, situated in the Upper Rhine Valley in southwest Germany. For the main monomer of technical SNFC products, 2-naphthalenesulfonate (2-NS), the concentration in the leachate was 170 µg l–1, which decreased to 9.5 µg l–1 at a distance of about 300 m from the boundary of the landfill. In the Merdingen tracer test field, the transport of these compounds was studied under more controlled conditions in two tracer experiments with (1) two model compounds, and (2) a technical SNFC product and uranine as a reference tracer. In these experiments, the monomeric naphthalenesulfonates and the SNFC with n=2 behave as conservative tracers. Thus, the findings of the landfill study were supported by these results. Higher molecular SNFC were strongly retarded, which is attributed to adsorption to soil particles. The results of the second tracer experiment suggest a degradation of 2-NS and 2,6-naphthalenedisulfonate (2,6-NDS) after adaptation of the microorganisms in the groundwater aquifer as a consequence of the first tracer experiment.

Analysis of Sulfonated Naphthalene−Formaldehyde Condensates by Ion-Pair Chromatography and Their Quantitative Determination from Aqueous Environmental Samples

An ion-pair solid-phase extraction (IPE), ion-pair chromatography (IPC) procedure with fluorescence detection for the quantitative analysis of sulfonated naphthalene-formaldehyde condensates (SNFC) was developed, which provides full resolution of SNFC up to a degree of condensation n = 5 and partial resolution up to n = 15. Liquid chromatography-electrospray ionization-mass spectrometry confirmed that SNFC elute in the order of condensation. Response factors in fluorescence detection proved to be mass-constant, thereby allowing us to determine total SNFC amounts. With this IPC method, the weight- and the number-average molecular weights of these high-volume production chemicals (kiloton per annum), used as synthetic tanning agents, concrete plasticizers, and dispersants, can be determined. Recoveries in IPE range from 73 to 85% in river Rhine water and from 79 to 93% in tap water for n = 2 to n = 7 with limits of detection of 3-8 ng/L for individual homologues from 500 mL of water. The IPE-IPC procedure was applied to samples of secondary industrial effluents, river Rhine water, a river bank filtrate, and a groundwater sample. SNFC up to n = 6 were detected in the treated effluents. Total concentrations ranged from 208 micrograms/L in a secondary treated SNFC production effluent to < 1.4 micrograms/L in groundwater. These first analyses suggest a widespread occurrence of the lower oligomers of SNFC in the aquatic environment.

Synthesis of Sulfonated Naphthalene-Formaldehyde Condensates and their Trace-analytical Determination in Wastewater and River Water

Naphthalenesulfonates and their condensates with formaldehyde (SNFC) are widely used in industrial processes, e.g. as plasticizers for concrete or as tanning agents. Based on their high aqueous solubility these compounds are expected to be eliminated incompletely in mechanical-biological treatment plants and to end up in the aquatic environment. Due to the lack of reference compounds the identification and quantification of these condensates in the aquatic environment was impossible in the past. This paper describes the synthesis of several condensates of 2-naphthalenesulfonate with formaldehyde. With the synthesized products as reference compounds it was possible for the first time to detect and quantify some sulfonated naphthalene-formaldehyde condensates in the aquatic environment. For this purpose characteristic peaks in the HPLC screening of wastewater and river water samples were compared with the corresponding peaks of a technical SNFC product. Three out of several paths on which these compounds enter the aquatic environment were identified. The identified compounds in the analyzed wastewater samples have concentrations between 0.14 and 110 μg/L. Synthese von sulfonierten Naphthalin-Formaldehyd-Kondensaten und ihre spurenanalytische Bestimmung in Abwässern und Oberflächenwässern Naphthalinsulfonate und ihre Kondensationsprodukte mit Formaldehyd (SNFC) finden in der Industrie, z. B. als Betonverflüssiger oder als synthetische Gerbstoffe, eine vielseitige Anwendung. Aufgrund ihrer guten Wasserlöslichkeit wird das Auftreten dieser Substanzgruppe in der aquatischen Umwelt vermutet. Mangels fehlender käuflicher Referenzverbindungen konnte das Vorkommen dieser Verbindungen in Oberflächenwässern und Abwässern bislang nicht untersucht und nachgewiesen werden. In dieser Arbeit wird die Synthese einzelner Kondensationsprodukte von 2-Naphthalinsulfonat mit Formaldehyd beschrieben. Mit Hilfe der synthetisierten Referenzsubstanzen und durch Vergleich charakteristischer Peaks in den Chromatogrammen realer Wasserproben mit den entsprechenden Peaks einer technischen Mischung von SNFC konnten mehrere dieser Substanzen zum ersten Mal nachgewiesen und quantifiziert werden. Drei verschiedene Eintragspfade konnten ermittelt werden. Die Konzentrationen in den untersuchten Abwässern bewegen sich zwischen 0.14 und 110 μg/L.

Synthesis of Sulfonated Naphthalene-Formaldehyde Condensates and their Trace-analytical Determination in Wastewater and River Water

Naphthalenesulfonates and their condensates with formaldehyde (SNFC) are widely used in industrial processes, e.g. as plasticizers for concrete or as tanning agents. Based on their high aqueous solubility these compounds are expected to be eliminated incompletely in mechanical-biological treatment plants and to end up in the aquatic environment. Due to the lack of reference compounds the identification and quantification of these condensates in the aquatic environment was impossible in the past. This paper describes the synthesis of several condensates of 2-naphthalenesulfonate with formaldehyde. With the synthesized products as reference compounds it was possible for the first time to detect and quantify some sulfonated naphthalene-formaldehyde condensates in the aquatic environment. For this purpose characteristic peaks in the HPLC screening of wastewater and river water samples were compared with the corresponding peaks of a technical SNFC product. Three out of several paths on which these compounds enter the aquatic environment were identified. The identified compounds in the analyzed wastewater samples have concentrations between 0.14 and 110 μg/L. Synthese von sulfonierten Naphthalin-Formaldehyd-Kondensaten und ihre spurenanalytische Bestimmung in Abwassern und Oberflachenwassern Naphthalinsulfonate und ihre Kondensationsprodukte mit Formaldehyd (SNFC) finden in der Industrie, z. B. als Betonverflussiger oder als synthetische Gerbstoffe, eine vielseitige Anwendung. Aufgrund ihrer guten Wasserloslichkeit wird das Auftreten dieser Substanzgruppe in der aquatischen Umwelt vermutet. Mangels fehlender kauflicher Referenzverbindungen konnte das Vorkommen dieser Verbindungen in Oberflachenwassern und Abwassern bislang nicht untersucht und nachgewiesen werden. In dieser Arbeit wird die Synthese einzelner Kondensationsprodukte von 2-Naphthalinsulfonat mit Formaldehyd beschrieben. Mit Hilfe der synthetisierten Referenzsubstanzen und durch Vergleich charakteristischer Peaks in den Chromatogrammen realer Wasserproben mit den entsprechenden Peaks einer technischen Mischung von SNFC konnten mehrere dieser Substanzen zum ersten Mal nachgewiesen und quantifiziert werden. Drei verschiedene Eintragspfade konnten ermittelt werden. Die Konzentrationen in den untersuchten Abwassern bewegen sich zwischen 0.14 und 110 μg/L.

Effects of Fly Ash and Superplasticizers on the Rheology of Cement Slurries

AbstractCementitious slurries composed of an oil well cement, a high calcium fly ash, a low calcium fly ash, and three commercially available superplasticizers (two different sulfonated naphthalene formaldehyde condensates and a sulfonated melamine formaldehyde condensate)were mixed to contrast the two fly ashes and to determine the effectiveness of each of the superplasticizing agents. Most commercial superplasticizers and cements are relatively expansive; therefore a partial substitution by fly ash and other by-products represents a substantial savings in both quantity of chemical admixture required and energy consumption for the manufacture of cement. In the cement/fly ash mixtures of 100/0, 90/10, 60/40, 40/60, and 10/90, with both high calcium fly ash and low calcium fly ash, the mixture containing the low calcium fly ash was consistently less workable. The rheological properties of the high vs. low calcium fly ash mixtures were controlled by the differences in fly ash particle size and the presence of irregular large particles, rather than by the differences in chemistry between the two. The low calcium fly ash was the coarser material.