A new insight into the mechanism of the scale inhibition: DLS study of gypsum nucleation in presence of phosphonates using nanosilver dispersion as an internal light scattering intensity reference

Upcycling of post-consumer polyethylene terephthalate bottles into aluminum-based metal-organic framework adsorbents for efficient orthophosphate removal

2-Phosphonobutane-1,2,4,-tricarboxylic acid (PBTC) is an orthophosphate compound widely used as an antiscalant chemical and corrosion inhibitor in manufacturing. However, PBTC poses persistent environmental concerns due to its stability and resistance to conventional water treatment. In addressing the issues of PBTC in aquatic systems, Al-based metal-organic frameworks (MOFs) have been developed and applied as sustainable adsorbents. The materials are synthesized from terephthalic acid (TPA) linkers derived from upcycling products of post-consumer polyethylene terephthalate (PET) bottles. The PET-derived linker was prepared using alkaline hydrolysis followed by acidification and employed in forming MIL-53 (Al), with a comparative assessment against the corresponding MOFs made from commercial-grade TPA. The structures and properties of the materials were characterized with microscopic and spectroscopic methods. The synthesized adsorbents achieved a phosphate adsorption capacity of 826 mg/g at pH 5, with kinetics fitting a pseudo-second-order model and isotherm patterns aligning with Langmuir, Freundlich, and Sips models, indicative of diverse adsorption on heterogeneous surfaces. The results highlight the role of electrostatic interactions and hydrogen bonding mechanisms in PBTC adsorption. The eco-friendly materials with high adsorption performance offer an innovative route for sustainable waste management and water purification.

Review of Phosphorus-Based Polymers for Mineral Scale and Corrosion Control in Oilfield

Production chemistry is an important field in the petroleum industry to study the physicochemical changes in the production system and associated impact on production fluid flow from reservoir to topsides facilities. Mineral scale deposition and metal corrosion are among the top three water-related production chemistry threats in the petroleum industry, particularly for offshore deepwater and shale operations. Mineral scale deposition is mainly driven by local supersaturation due to operational condition change and/or mixing of incompatible waters. Corrosion, in contrast, is an electrochemical oxidation-reduction process with local cathodic and anodic reactions taking place on metal surfaces. Both mineral scaling and metal corrosion can lead to severe operational risk and financial loss. The most common engineering solution for oilfield scale and corrosion control is to deploy chemical inhibitors, including scale inhibitors and corrosion inhibitors. In the past few decades, various chemical inhibitors have been prepared and applied for scaling and corrosion control. Phosphorus-based polymers are an important class of chemical inhibitors commonly adopted in oilfield operations. Due to the versatile molecular structures of these chemicals, phosphorus-based polymeric inhibitors have the advantage of a higher calcium tolerance, a higher thermal stability, and a wider pH tolerance range compared with other types of inhibitors. However, there are limited review articles to cover these polymeric chemicals for oilfield scale and corrosion control. To address this gap, this review article systematically reviews the synthesis, laboratory testing, and field applications of various phosphorus-based polymeric inhibitors in the oil and gas industry. Future research directions in terms of optimizing inhibitor design are also discussed. The objective is to keep the readers abreast of the latest development in the synthesis and application of these materials and to bridge chemistry knowledge with oilfield scale and corrosion control practice.

Assessment of self-doped poly (5-nitro-2-orthanilic acid) as a scaling inhibitor to control the precipitation of CaCO3 and CaSO4 in solution

Self-doped- and nitro-polyanilines have become a widely used strategy to optimize the electronic and vibratory spectra of polymeric building blocks in various applications. We report the synthesis of poly (5-nitro-2-orthanilic acid) by an aniline-initiated oxidative polymerization reaction. The polymer is characterized by spectroscopic techniques, elemental shapes, cyclic voltammetry, electrical conductivity, and microscopic and thermal measurements. The hydrophilic and hydrophobic nature of the supports provided the formation of amphiphilicity as judged by SEM. Thermogravimetric measurements reveal thermal stability up to 500 °C and glass temperature (T_g) observed at 240 °C. Electrical conductivity decreases as the temperature rises at the different frequencies used, reflecting the semiconducting nature in the extrinsic range, which is characterized by high carriers and low mobility. The presence of these electron residues causes a decrease in efficiency and increases the thermal conductivity. Dielectric measurements have shown that permittivity decreases gradually at lower levels, mainly due to the transport of charging carriers, resulting in higher performance. The testing of the copolymer as a new scale blocker has resulted in moderate to fairly high performance. This effect is attributed to the change in polymer geometry using intramolecular H-bonding group -SO₃H and a chain polymer in an aqueous medium.

A Review of Green Scale Inhibitors: Process, Types, Mechanism and Properties

In the present time, more often, it has been seen that scaling has grown as widely and caused problems in the oilfield industry. Scaling is the deposition of various salts of inorganic/organic materials due to the supersaturation of salt-water mixtures. Many works have been proposed by researchers using different methods to solve the problem, of which scale inhibition is one of them. The scale inhibitors, particularly for antiscaling, have derived from natural and synthetic polymers. Among different polymers, inorganic and organic compounds (polyphosphates, carboxylic acid, ethylenediaminetetraacetic acid (EDTA), etc.) can effectively manage the oilfield scales of which many are toxic and expansive. Scale inhibitors of alkaline earth metal carbonate and sulfates and transition metal sulfide are commonly used in oilfield applications. Scale inhibition of metallic surfaces is an essential activity in technical, environmental, economic, and safety purposes. Scale inhibitors containing phosphorus appear to have significant achievements in the inhibition process despite its toxicity. However, phosphorus-based inhibitors can serve as supplements prompting eutrification difficulties. Besides these increasing environmental concerns, green scale inhibitors are renewable, biodegradable, and ecologically acceptable that has been used to prevent, control, and retard the formation of scale. Considering the facts, this review article summarized the concept of scale, various green scale inhibitors, types, mechanisms, comparative performance, significance, and future aspects of green scale inhibitors, which will shed light and be helpful for the professionals working in the oil and gas industries.

The synthesis of polyaspartic acid derivative PASP-Im and investigation of its scale inhibition performance and mechanism in industrial circulating water

A polyaspartic acid derivative (PASP-Im) as a novel scale inhibitor was synthesized by a simple green synthesis route with polysuccinimide and iminodiacetic acid as the starting materials. The as-synthesized PASP-Im was characterized via nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectrometry (FT-IR), and its scale inhibition performance was evaluated by a static scale inhibition method. Moreover, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and density functional theory computational studies were conducted to explore the scale inhibition mechanism of PASP-Im. The findings indicate that the as-synthesized PASP-Im exhibits better antiscale performance against the CaCO₃ deposits than the unmodified PASP because of the introduction of iminodiacetic acid group. It also can change the crystallization path of calcium carbonate from stable calcite to vaterite that is dispersible in water, thereby resulting in great changes in the morphology of the CaCO₃ scale. Furthermore, the O and N atoms in the negatively charged functional groups (such as –NH₂ and –COOH) of PASP-Im can interact with calcium ions to block the active growth point of CaCO₃ crystals, which also accounts for the excellent antiscale performance of PASP-Im. With new insights into the synergy between the functional groups of the antiscale molecule and scale-forming ions, this approach would be helpful towards the development of novel high-performance anti-scaling macromolecules.

A polyaspartic acid derivative (PASP-Im) as a novel scale inhibitor was synthesized by a simple green synthesis route with polysuccinimide and iminodiacetic acid as the starting materials.

Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

Gypsum scaling in reverse osmosis (RO) desalination process is studied in presence of a novel fluorescent 1,8-naphthalimide-tagged polyacrylate (PAA-F1) by fluorescent microscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) and a particle counter technique. A comparison of PAA-F1 with a previously reported fluorescent bisphosphonate HEDP-F revealed a better PAA-F1 efficacy, and a similar behavior of polyacrylate and bisphosphonate inhibitors under the same RO experimental conditions. Despite expectations, PAA-F1 does not interact with gypsum. For both reagents, it is found that scaling takes place in the bulk retentate phase via heterogeneous nucleation step. The background “nanodust” plays a key role as a gypsum nucleation center. Contrary to popular belief, an antiscalant interacts with “nanodust” particles, isolating them from calcium and sulfate ions sorption. Therefore, the number of gypsum nucleation centers is reduced, and in turn, the overall scaling rate is diminished. It is also shown that, the scale formation scenario changes from the bulk medium, in the beginning, to the sediment crystals growth on the membrane surface, at the end of the desalination process. It is demonstrated that the fluorescent-tagged antiscalants may become very powerful tools in membrane scaling inhibition studies.

Investigating the effect of temperature on calcium sulfate scaling of reverse osmosis membranes using FTIR, SEM-EDX and multivariate analysis

Membrane fouling is one of the major hurdles in widespread use of seawater reverse osmosis (SWRO) in desalination industry. There are various factors that affect the inorganic fouling or scaling of Reverse osmosis (RO) membranes. In this research, the effect of temperature on scaling of RO and Graphene oxide (GO) coated RO membrane by calcium sulfate was investigated. It was found that the increase in temperature enhanced the membrane scaling which was evident by the severe flux decline over time leading to increase in mass of crystals precipitated (M_t) and thickness of the scale layer. There was strong positive correlation (R² ≥ 0.97) noted between M_t and the temperature. The results of SEM-EDX and XRD confirmed that the crystals formed under the experimental conditions are gypsum. Results of this research showed that there was no significant difference in terms of crystal morphology, scaling intensity and mechanism after modifying RO membrane with GO. It was noted that the morphology of the crystals varied from rod shaped to rosette structures under the influence of temperature. Furthermore, the results of FTIR helped to understand the mechanism of interaction between the membranes and the gypsum. The hydrophilicity of the scaled membrane was also measured to investigate the changes in the properties of the membrane after scaling.