Investigation of fig leaf extract as a novel environmentally friendly antiscalent for CaCO3 calcareous deposits

Influence of Different Ions on Pulse Electrodeposition of CaCO3 Scales in the Simulated Seawater

In the circulating water system of coastal power plants, various kinds of ions have a great influence on the formation and growth of CaCO3 scales. This paper focuses on investigating the influence of existing ions on the pulse electrodeposition behaviors of CaCO3 scales. Different concentrations of ions, such as Fe3+, Mg2+, PO43- and SiO32-, are introduced to simulate the actual seawater environment, and their influence on the CaCO3 scale deposition behaviors is assessed by linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy tests. The surface coverage of the CaCO3 scale layer is evaluated through the residual current density and polarization resistance values, while the crystal structure and surface compactness of the layer are confirmed by the scanning electron microscope and X-ray diffractometer tests. Results indicate that high concentrations of Mg2+, Fe3+, and PO43- ions have the most significant inhibitory effect on the pulse electrodeposition of CaCO3 scales, among which the inhibition effect of Mg2+ ions is mainly reflected in the change of crystal morphology of CaCO3, that is, the crystallization growth process is inhibited. The inhibition effect of PO43- ions is mainly reflected in the gradually reduced coverage and density of CaCO3 crystals on the electrode surface, suggesting that the crystallization nucleation process is inhibited, while Fe3+ ions have a certain inhibition effect on both the crystallization nucleation and growth processes. Furthermore, lower concentrations of SiO32- ions also display a significant inhibition effect on the crystallization nucleation and growth process, and the inhibition effect weakens with increased concentration. This study provides a theoretical basis for exploring the removal of ions in the industrial water softening field.

Mitigation of Mineral Deposition in Carbonate and Sandstone Rocks Using Green Scale Inhibitors

Waterflooding is potentially a viable approach to enhance oil recovery, though its efficacy can profoundly be compromised due to formation damage as a result of inorganic scale deposition. In this study, a series of high-temperature core flooding experiments were conducted to evaluate two green scale inhibitors (SIs) of folic acid and inulin as alternative inhibitors to mitigate mineral deposition. The co-injection of two incompatible brines (with and without SIs) for two flow rates of 0.5 and 3 mL/min into two core samples of dolomite and sandstone was experimentally investigated. The results showed that folic acid would inhibit scale formation as much as 45-49%, at the lower flow rate, compared to inulin with an efficiency of 29-39%, at the higher flow rate. Moreover, computed tomography imaging technique showed that scale formation and fine migration would be dominant mechanisms for formation damage in dolomite and sandstone rocks, respectively. The theoretical study based on surface energy also confirmed the experimental results in terms of the work of adhesion which showed that folic acid would mitigate the calcite deposition on rock surfaces approximately 55%. Finally, a phosphonate-based commercial SI was compared with the green SIs which reaffirmed their potencies.

New application of brown sea algae as an alternative to phosphorous-containing antiscalant

Over the past decade, green chemistry research has focused on the importance of protecting the environment, especially to align with UN sustainable development goals by avoiding the use of chemicals that are harmful to the environment and society. In this study, an aqueous extract derived from brown sea algae was prepared and its performance as antiscalant was compared to commercial antiscalant (Hydroxy ethylidene, 1-Diphosphonic Acid, HEDP) and evaluated using electrochemical measurements, conductivity and standard NACE test in addition to microscopic examination. It was found that there is a significant inhibition efficiency of brown algae towards the tested scales as HEDP. The obtained extract had the ability to prevent precipitation of calcium sulphate, calcium carbonate, barium sulphate and strontium carbonate with percent inhibition of 100%, 80%, 84% and 75%, respectively. The inhibitory effect of the extract can be attributed to the presence of carboxylate and hydroxyl groups that are adsorbed on the surface sites and disturb the normal crystal growth of the scale. The results of the study will lead to the discovery of further new applications of ecologically, cost-effective, renewable source and benign antiscalant that can be considered as an alternative to non-green technologies particularly those used in the food and pharmaceutical industries as well as in desalination plants.

Effect of the passive films on CaCO3 scale depositing on Q235 steel: Electrochemical and surface investigation

The deposition of the CaCO₃ scale in circulating cooling water is a common and serious concern in the industry, which hinders the heat transfer, reduces water flow and blocks membrane filters. This paper aims at studying the effect of the γ-Fe₂O₃, Fe₂(MoO₄)₃·γ-Fe₂O₃ and FePO₄·γ-Fe₂O₃ passive films on CaCO₃ scale deposition on Q235 steel by electrochemical methods, including linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) tests. The scale and corrosion inhibition performance of the passive films was evaluated by the residual current density (i_r) and charge transfer resistance (R_ct) values. Electrochemical results suggested that the passive films could inhibit corrosion and reduce the CaCO₃ scale deposition on Q235 steel and the FePO₄·γ-Fe₂O₃ complex passive film showed the best anti-scaling effect. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) tests showed that the passive films could lead to a decrease in the proportion of aragonite to calcite under cathodic water reduction conditions and the composition of the FePO₄·γ-Fe₂O₃ complex passive film could deform the CaCO₃ crystal.

Scale inhibition in industrial water systems using chitosan‐alginate mixture

The study aims to establishing the possibility of using eco‐friendly natural polymers to formulate scale inhibitor for industrial water applications. The performance of a blend of two natural polymers, chitosan and sodium alginate as scale inhibitor in comparison with a commercially available inhibitor formulation, HEDP (Hydroxyethylidene, 1‐Diphosphonic Acid), is carried out using electrochemical measurements, conductivity and NACE test complemented with crystals morphology characterization using optical and electronic microscopic examination. Overall results show that chitosan is more efficient for the inhibition of calcium carbonate scales formation, whilst it has poor efficiency in the inhibition of sulfate scales, whereas sodium alginate has the highest efficiency in inhibiting calcium sulfate scales. However, the addition of sodium alginate to chitosan, as a package, has a dual control effect on carbonate and sulfate scale formation with good efficiency compared to HEDP. This new phosphorus‐free package represents an effective antiscalant to have green environment.

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.

Raphanus sativus L. Extract as a Scale and Corrosion Inhibitor for Mild Steel in Tap Water

The Raphanus sativus L. ethanol extract was prepared by radish cake maceration in ethanol end tested as a scale and corrosion inhibitor of mild steel in tap water. Antiscalant efficiency was tested with electrochemical and thermal scaling techniques, and changes in hardness content were determined titrimetrically. No deposits were found on the metal surface at the extract concentration of 10 mL/L in chronoamperometry test, and scaling suppression was established 5 times in thermal scaling conditions. The linear polarization resistance technique was used to determine corrosion rate. Inhibition efficiency was found to be 75% in thermal scaling conditions. The formation of the surface film was responsible for both scaling and corrosion suppression on mild steel surface as was established with FT-IR spectroscopy and SEM. The surface film was found to contain polymerization products of isothiocyanates.

Synthesis of Poly (Citric Acid-Co-Glycerol) and Its Application as an Inhibitor of CaCO3 Deposition

This investigation determined a feasible route to prepare hyperbranched polyesters involving citric acid (CA) and glycerol (GLC) monomers (CA-co-GLC) using a thermal polycondensation method. The synthesized copolymer was characterized using Fourier transform infrared spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The ability of CA-co-GLC to inhibit deposition of inorganic scales such as calcium carbonate was investigated under varying temperature and pH medium. The evaluation of inhibition efficiency (IE) was conducted using the static scale inhibition method. The mechanism of the inhibitor's action was investigated via growth solution analysis, measurement conductivity, and analysis of CaCO₃ using FT-IR and scanning electron microscopy. The results obtained showed that the CA-co-GLC had good IE at an elevated temperature reaching 75% at 100 °C, pH 7.5, and 10 ppm copolymer dose. Using the same dose, the IE reached 66% at 50 °C and pH 10. The CA-co-GLC did not chelate Ca²⁺ in water, but led to a change in polymorphism, making it brittle and able to slip easily from the surface. Its action principally prevented the adhesion of calcium carbonate onto the surface.

The inhibition of crystal growth of gypsum and barite scales in industrial water systems using green antiscalant

Mineral scale is a major flow assurance problem in industrial water systems. The antiscale properties of sunflower (Helianthus annuus) seed extract for CaSO4 and BaSO4 scales were investigated using NACE and conductivity tests, respectively. Comparative studies between the extract and 1-hydroxyethane-1,1-diphosphonic acid (HEDP), as commercial antiscalants, were done. The results revealed that the inhibition of CaSO4 scales using sunflower seed extract reached 100%, while HEDP achieved a maximum inhibition of 88%. Moreover, the maximum inhibition of BaSO4 scale in the presence of the extract was 84% compared with 86% in the presence of HEDP. Also microscopic examination showed that both inhibitors modified CaSO4 and BaSO4 crystals.

Inhibition of calcium carbonate deposition on stainless steel using olive leaf extract as a green inhibitor

The antiscale properties of the aqueous extract of olive (Olea europaea L.) leaves as a natural scale inhibitor for stainless steel surface in Hammam raw water were investigated using chronoamperometry (CA) and electrochemical impedance spectroscopy techniques in conjunction with a microscopic examination. The X-ray diffraction analysis reveals that the scale deposited over the pipe walls consists of pure CaCO₃ calcite. The CA, in accordance with electrochemical impedance spectra and scanning electron microscopy, shows that the inhibition efficiency increases with increasing extract concentration. This efficiency is considerably reduced as the temperature is increased.

Inhibitory effect of glutamic acid on the scale formation process using electrochemical methods

The formation of calcium carbonate CaCO3 in water has some important implications in geoscience researches, ocean chemistry studies, CO2 emission issues and biology. In industry, the scaling phenomenon may cause technical problems, such as reduction in heat transfer efficiency in cooling systems and obstruction of pipes. This paper focuses on the study of the glutamic acid (GA) for reducing CaCO3 scale formation on metallic surfaces in the water of Bir Aissa region. The anti-scaling properties of glutamic acid (GA), used as a complexing agent of Ca(2+) ions, have been evaluated by the chronoamperometry and electrochemical impedance spectroscopy methods in conjunction with a microscopic examination. Chemical and electrochemical study of this water shows a high calcium concentration. The characterization using X-ray diffraction reveals that while the CaCO3 scale formed chemically is a mixture of calcite, aragonite and vaterite, the one deposited electrochemically is a pure calcite. The effect of temperature on the efficiency of the inhibitor was investigated. At 30 and 40°C, a complete scaling inhibition was obtained at a GA concentration of 18 mg/L with 90.2% efficiency rate. However, the efficiency of GA decreased at 50 and 60°C.