Croton lechleri Extracts as Green Corrosion Inhibitors of Admiralty Brass in Hydrochloric Acid.

Croton lechleri, commonly known as Dragon's blood, is a tree cultivated in the northwest Amazon rainforest of Ecuador and Peru. This tree produces a deep red latex which is composed of different natural products such as phenolic compounds, alkaloids, and others. The chemical structures of these natural products found in C. lechleri latex are promising corrosion inhibitors of admiralty brass (AB), due to the number of heteroatoms and π structures. In this work, three different extracts of C. lechleri latex were obtained, characterized phytochemically, and employed as novel green corrosion inhibitors of AB. The corrosion inhibition efficiency (IE%) was determined in an aqueous 0.5 M HCl solution by potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopy, measuring current density and charge transfer resistance, respectively. In addition, surface characterization of AB was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques. Chloroform alkaloid-rich extracts resulted in IE% of 57% at 50 ppm, attributed to the formation of a layer of organic compounds on the AB surface that hindered the dezincification process. The formulation of corrosion inhibitors from C. lechleri latex allows for the valorization of non-edible natural sources and the diversification of the offer of green corrosion inhibitors for the chemical treatment of heat exchangers.

Experimental and Theoretical Studies on Extract of Date Palm Seed as a Green Anti-Corrosion Agent in Hydrochloric Acid Solution.

Extracts from plant materials have great potential as alternatives to inorganic corrosion inhibitors, which typically have harmful consequences. Experimental and theoretical methodologies studied the effectiveness of agricultural waste, namely, date palm seed extract as a green anti-corrosive agent in 0.5 M hydrochloric acid. Experimental results showed that immersion time and temperature are closely related to the effectivity of date palm seed as a corrosion inhibitor. The inhibition efficiency reduced from 95% to 91% at 1400 ppm when the immersion time was increased from 72 h to 168 h. The experimental results also indicated that the inhibition efficiency decreased as the temperature increased. The presence of a protective layer of organic matter was corroborated by scanning electron microscopy. The adsorption studies indicated that date palm seed obeyed Langmuir adsorption isotherm on the carbon steel surface, and Gibbs free energy values were in the range of -33.45 to -38.41 kJ·mol-1. These results suggested that the date palm seed molecules interacted with the carbon steel surface through mixture adsorption. Theoretical calculations using density functional theory showed that the capability to donate and accept electrons between the alloy surface and the date palm seed inhibitor molecules is critical for adsorption effectiveness. The HOMO and LUMO result indicated that the carboxyl (COOH) group and C=C bond were the most active sites for the electron donation-acceptance type of interaction and most auxiliary to the adsorption process over the Fe surface.

Biocompatible Wax-Based Microcapsules with Hermetic Sealing for Thermally Triggered Release of Actives.

We present a microfluidic approach that utilizes temperature-responsive and biocompatible palm oil as the shell material in microcapsules to simultaneously achieve hermetic sealing as well as on-demand temperature-triggered release of the encapsulated actives. Unlike common paraffin waxes (e.g., eicosane), microcapsule shells comprising palm oil do not form pores or cracks during freezing and provide a hermetic seal, a nearly perfect seal that separates the core containing the actives from the surrounding environment over a prolonged period of time. This allows effective isolation and protection of complex cargoes such as small molecules with high diffusivity, strong acids, and cosmetic actives including niacinamide. Moreover, the palm oil shell melts above the defined melting temperature, allowing the on-demand release of the encapsulated actives. Furthermore, palm oil is biocompatible, is edible, and leaves a minimal footprint when used in personal care and cosmetic products, offering new perspectives in the design of microcapsules for cosmetic applications.

Eco-friendly isolation and characterization of nanochitin from different origins by microwave irradiation: Optimization using response surface methodology.

The extraction of nanochitin from marine waste has attracted great industrial interest due to its unique properties, namely biodegradability, biocompatibility and as a functional reinforcing agent. Conventional acid hydrolysis isolation of nanochitin requires high temperatures and acid concentration, time and energy. Herein, for the first time, microwave irradiation method was used as an eco-friendly approach to isolate nanochitin from different sources. The isolation conditions were optimized through an experimental Box-Behnken design using surface response methodology. The data showed optimal conditions of 1 M HCl, 10.00 min and 124.75 W to obtain lobster nanocrystals; 1 M HCl, 14.34 min and 50.21 W to obtain shrimp nanocrystals; and 1 M HCl, 29.08 min and 54.08 W to obtain squid pen nanofibres, reducing time and HCl concentration. The obtained isolation yields where of 85.30, 79.92 and 80.59 % for lobster, shrimp and squid, respectively. The morphology of the nanochitins was dependent of the chitin origin, and the lengths of the nanochitins were of 314.74, 386.12 and > 900 nm for lobster, shrimp and squid pen, respectively. The thermal stability of the ensuing nanochitins was maintained after treatment. The results showed that nanochitin could be obtained by using an eco-friendly approach like microwave irradiation.

Exploration of Sunflower Oil As a Renewable Biomass Source to Develop Scalable and Highly Effective Corrosion Inhibitors in a 15% HCl Medium at High Temperatures.

The feasibility study of utilizing sunflower oil as renewable biomass source to develop highly effective inhibitors for mild steel corrosion (MS) in the 15% HCl medium was done by weight loss, potentiodynamic polarization (PDP), dynamic electrochemical impedance spectroscopy (DEIS), and electrochemical impedance spectroscopy (EIS), supported with energy-dispersive X-ray (EDX), atomic force microscopy (AFM), and field-emission scanning electron microscope (FESEM) techniques. Moreover, a complementary theoretical investigation was carried out to clarify the inhibition mechanism of inhibitors by density functional theory (DFT), density functional based tight-binding (DFTB), and molecular dynamics (MD) simulation approaches. The obtained results confirm that sunflower-oil-based corrosion inhibitor (SFOCI) has a significant anticorrosion property toward the dissolution of MS in 15% HCl solution in the temperature range 20-80 °C. In addition, the results show that SFOCI could provide an inhibition efficiency of 98 and 93% at 60 and 80 °C, respectively. The inhibition mechanism of SFOCIs was mixed-type and their adsorption on the surface of MS was mainly chemisorption. The FESEM and EDX studies proved the presence of SFOCI molecules on the surface of MS. In addition, the adsorption energy of SFOCI indicated an intense interaction between the inhibitor and surface of Fe. The results of this study could open a new window for the design and development of scalable and effective eco-friendly vegetable-oil-based corrosion inhibitors for highly corrosive solutions at high temperatures.

Evaluation on the physicochemical and digestive properties of melanoidin from black garlic and their antioxidant activities in vitro.

As the important compounds in black garlic, the physicochemical properties and bioactivities of melanoidin (MLD) were investigated in this study. The results showed that MLD possessed strong metal-ion chelating capacity and radical scavenging activities which were positively correlative with molecular weight (MW). During the simulated digestion in vitro, the ultraviolet absorption, browning degree and MW distribution of MLD remained the same as initial. It proved that the MLD from black garlic could be indigestible like the dietary fiber with little loss of volatile compounds and polysaccharides. Remarkably, the bioactivities of MLD were reduced significantly under the treatment of α-amylase or hydrochloric acid, while they were stable and retained over 60% after adding pepsin and pancreatin. This study provides fundamental evidences for further research and widely application of MLD and black garlic in the production of functional food or food additives.

Structural characteristics of oxalate-soluble polysaccharides from Norway spruce (Picea abies) foliage.

Structurally different polymers were derived from Picea abies foliage by successive extraction with water (PAW), HCl solution (PAA) and (NH4)2C2O4 solution (PAO). The P. abies foliage was found to contain basically low-methoxyl pectin extractable with an (NH4)2C2O4 solution. PAW was shown to comprise primarily arabinogalactan-proteins (AGPs); PAA was composed of mixed AGPs and pectic polysaccharides, with the latter prevailing; and polysaccharide PAO isolated in the highest yield included chiefly pectic polysaccharides. The major constituents of PAO were low-methoxyl and low-acetylated 1,4-α-d-galacturonan and partially acetylated RG-I. The sugar side chains of RG-I contained chiefly highly branched 1,5-α-l-arabinan and arabinogalactan type I as a minor constituent. RG-I whose side chains had 1,5-α-l-arabinan represented short regions alternating with non-acetylated and unmethylesterified galacturonan regions. In addition to pectins, polysaccharide PAO contained AGPs, xylanes and glucomannans, indicating that these polysaccharides are in an intimate interaction.

Effects of heat-moisture and acid treatments on the structural, physicochemical, and in vitro digestibility properties of lily starch.

Starch extracted from lily bulb (Lilium brownii var. Viridulum Baker) was modified via heat-moisture treatment (HMT) at different moisture levels (15-35%) and acid treatment (AT) with hydrochloric acid at five different concentrations (0.25-2.0 M). The effects of HMT and AT on the physicochemical properties and in vitro digestibility of lily starch were investigated. HMT and AT led to the clustering of the starch granules, whose surface became rougher, thereby increasing the particle size. X-ray diffraction results showed that HMT increased the relative crystallinity and transformed the crystalline structure from B- to A-type. The relative crystallinity and X-ray patterns of the AT starch significantly increased. The swelling power of HMT and AT starch was significantly reduced, whereas the solubility of HMT starch decreased. The solubility of AT starch was significantly higher than that of native starch (NS) (p < 0.05). Differential scanning calorimetry revealed that the gelatinization temperature of lily starch was higher than that of NS after two modifications, whereas the gelatinization enthalpy of the NS was lower than that of the modified samples. The starch with HMT at 25% showed the highest resistant starch content of 44.15% in cooked samples.

The structure-property relationships of acid- and alkali-extracted grapefruit peel pectins.

Structure and properties of pectin can be affected by extraction methods. In this study, grapefruit peel pectins extracted by HCl (at pH 1 [P1], 2 [P2], and 3 [P3]) and NaOH (at pH 9 [P9], 10 [P10], and 11 [P11]) were prepared and characterized. Atomic force microscopy (AFM) provided direct evidence of complex nano-structural patterns of pectins and revealed cross-linked networks of P10 and P11. Small-angle X-ray scattering (SAXS) demonstrated that P1, P2, and P3 possessed a relatively extended conformation, whereas P9, P10, and P11 displayed a three-dimensional structure and folded conformation. The compact and extended conformations of P3 contributed to its high viscosity in solution and the stability of the formed emulsion (75%). Porous surface and larger three-dimensional nanostructure (Dmax: 23 nm) of P10 facilitated its ion-binding capacity. Our results provide valuable insight into relationship between extraction methods and structure-properties of pectin, facilitating design of functional pectins.

Direct versus Sequential Analysis of Procyanidin- and Prodelphinidin-Based Condensed Tannins by the HCl-Butanol-Acetone-Iron Assay.

In this study, we optimized the HCl-butanol-acetone-iron (HBAI) assay for the analysis of B-linked procyanidin (PC) and prodelphinidin (PD) condensed tannins (CTs) by direct analysis of whole tissue and sequential analysis of acetone-water extracts and insoluble residues prepared from forage, woody plant, food, and food byproduct samples. Yields of anthocyanidins (cyanidin and delphinidin) were optimized by heating ≤0.25 mg mL-1 CT standards, 1 mg mL-1 tissue, or 1-2 mg mL-1 acetone-water fractioned tissue for 3 h at 70 °C in medium containing 5% concentrated HCl, 6.7% total water, 50% acetone, 42% n-butanol, and 0.15% ammonium iron(III) sulfate dodecahydrate. Accurate quantitation required CT standards of known purity sourced from the same tissue being analyzed. Both analysis methods provided comparable estimates of total CTs for most PD-rich samples, but only the sequential method gave good recovery and accurate estimates of CTs in most PC-rich samples.

Green Eucalyptus leaf extract: A potent source of bio-active corrosion inhibitors for mild steel.

Eucalyptus leaves extract (ELE) inhibition impact toward mild steel (MS) corrosion in the HCl solution was examined by combined experimental and computational studies. The degree of inhibition was investigated by EIS and polarization test. The EIS analysis results showed that the increase of ELE concentration led to the significant increment of charge transfer resistance. An inhibition efficiency of ~88% was obtained using 800 ppm ELE after 5 h exposure. Polarization test results indicated the mixed inhibition effects of ELE with slight cathodic prevalence. The icorr values for the uninhibited and inhibited (800 ppm ELE) samples were 0.93 µA/cm2 and 0.25 µA/cm2, respectively. The ELE molecules adsorption on the surface of MS followed a Langmuir isotherm. Furthermore, the molecular simulation results evidenced the adsorption of ELE compounds on the iron surface.

Shear rheological properties of acid hydrolyzed insoluble proteins from Chlorella protothecoides at the oil-water interface.

Microalgae are promising protein sources due to their overall high protein content. The low aqueous-solubility of microalgae proteins, however, limits their application in food, pharmaceutical or personal care systems, unless solubility is enhanced by e.g. hydrolysis. In this study, we examined the interfacial rheological properties at the oil-water interface of insoluble microalgae protein-rich fraction from Chlorella protothecoides and their hydrolysates prepared by hydrolysis in hydrochloric acid at 65 °C (Hydrolysates 65) and 85 °C (Hydrolysates 85). Results showed increased interfacial activity of the insoluble microalgae protein-rich fraction after hydrolysis: Hydrolysates 65 and Hydrolysates85 had higher interfacial storage Gi' and loss moduli Gi″ compared to the untreated insoluble microalgae protein-rich fraction. Increasing amounts of soluble protein fragments mixed with insoluble protein particles in hydrolysates stabilized interfacial layers. The influence of pH on the interfacial behavior of samples was also determined and revealed that Gi' and Gi″ values of treated and untreated protein fractions decreased as pH increased beyond their isoelectric points due to increasing electrostatic repulsions between adsorbed protein fragments and aggregates. The high viscoelasticity of the acid-hydrolyzed insoluble microalgae protein-rich fraction at the oil-water interface indicates a high potential for them to be useful in stabilizing emulsion-based products.

Evaluation of Ficus tikoua leaves extract as an eco-friendly corrosion inhibitor for carbon steel in HCl media.

An effective and biodegradable Ficus tikoua leaves extract was studied as a corrosion inhibitor for carbon steel in hydrochloric acid. Systematic electrochemical experiments and morphological characterization were carried out to investigate the properties of the corrosion inhibitor. Meanwhile, quantum chemical calculations were performed to aid further understanding of the electrochemical mechanism. The electrochemical results reveal that the extract inhibitors act as a mixed-type with an inhibition efficiency up to 95.8% at 298 K. Moreover, this extract shows good inhibory activity at a wide range of temperatures and the corresponding results were further confirmed by morphological analysis. The chemical formulae of these major components are fully optimized in the DFT with B3LYP in the gas phase and the base set is 6-311++G (d, p).

Supplementing multi-functional groups to polysulfone membranes using Azadirachta indica leaves powder for effective and highly selective acid recovery.

Moderate and eco-pleasing ion-exchange trade membranes are in need to recover acid from industrial waste. Present study is focused on incorporation of plant waste (Azadirachta indica, neem leaves powder (NP)) of different composition as filler to polysulfone (PSf) membrane matrix to achieve acid recovery. Membranes were characterized, their chemical, mechanical and thermal stabilities and effectiveness in acid recovery via diffusion has been inspected. Multi-functional groups (-COOH, -NH2, -OH, -OAc, -C = O) present in different components of NP contributes in their own means in H+ ion transportation through membrane in acid recovery. They assisted formation of hydrogen bond and provided channels for ion permeation, and facilitated selective transportation of H+ ion over Fe2+ ions and explained mechanism is in accordance with Grotthuss-type and vehicle mechanism. Membrane with 15% of NP showed better performance in terms of ion exchange capacity (IEC) and acid recovery, at optimum concentration of NP, composite the membrane showed highest IEC values of 3.9771 mmol/g, UH+ value of ≈46.499 × 10-3 m/h and greater separation factor ≈154, which is higher than commercially available DF-120 membrane. An original thought of utilizing NP in membrane matrix opens up promising opportunities for extremely straightforward, easy, cost-effective and greener methods of recovery acid.

α-methylation and α-fluorination electronic effects on the regioselectivity of carbonyl groups of uracil by H and triel bonds in the interaction of U, T and 5FU with HCl and TrH3 (Tr = B, Al).

Quantum chemical calculations at the ωB97XD/6-311++G(d,p) level of theory have been executed to investigate the effect of substituents via hydrogen-bonded and triel-bonded complexes between uracil (U), thymine (T) and 5-fluorouracil (5FU) with HCl for the former complexes, and with BH3 and AlH3 for the latter complexes. These calculations are supported by single-point energy calculations at MP2/6-311++G(d,p) and CCSD/6-31 + G(d,p) levels of theory, Natural Bond Orbital (NBO) and Molecular Electrostatic Potentials (MEPs) analyses, and global/local reactivity descriptors. The results reveal that triel-bonded complexes are strongly bounded than hydrogen-bonded ones, and Al-containing dimers stronger than B-containing ones. In addition, as the central triel atom grows in size, B-containing dimers (B-O triel bond) are accompanied by weak B-H⋯O unconventional H-bonds. According to local reactivity descriptors, the B-O triel bond is hard-hard interaction that indicates that the association is primarily charge controlled, while the Al-O triel bond is soft-soft interaction that is primarily orbital controlled. In both Hydrogen as well as triel-bonded complexes, the α-methylation slightly overestimates the binding strength of U, while the α-fluorination exerts the opposite role by underestimating the binding strength of U. In overall, the effect of substituents on the bond strength and thus on the regioselectivity is very small, suggesting a competition between the two carbonyl groups in terms of structures and binding energies.

Treatment of corn with lactic acid or hydrochloric acid modulates the rumen and plasma metabolic profiles as well as inflammatory responses in beef steers.

BACKGROUND: High-grain diets that meet the energy requirements of high-producing ruminants are associated with a high risk of rumen disorders. Mild acid treatment with lactic acid (LA) has been used to modify the degradable characteristics of grains to improve the negative effects of high-grain diets. However, the related studies mainly focused on dairy cows and explored the effects on rumen fermentation, production performance, ruminal pH and so forth. And up to date, no studies have reported the hydrochloric acid (HA) treatment of grains for ruminant animals. Therefore, based on metabolomics analysis, the aim of this study was to evaluate the effects of treatment of corn by steeping in 1% LA or 1% HA for 48 h on the rumen and plasma metabolic profiles in beef steers fed a high corn (48.76%) diet with a 60:40 ratio of concentrate to roughage. The inflammatory responses of beef cattle fed LA- and HA-treated corn were also investigated. RESULTS: Based on ultra-high-performance liquid tandem chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) metabolomics and multivariate analyses, this study showed that steeping corn in 1% LA or 1% HA modulated the metabolic profiles of the rumen. Feeding beef steers corn steeped in 1% LA or 1% HA was associated with lower relative abundance of carbohydrate metabolites, amino acid metabolites, xanthine, uracil and DL-lactate in the rumen; with higher ruminal pH; with lower concentrations of acetate, iso-butyrate and iso-valerate; and with a tendency for lower ruminal lipopolysaccharide (LPS) concentrations. Moreover, the data showed lower concentrations of plasma C-reactive protein, serum amyloid A, haptoglobin, interleukin (IL)-1ß and IL-8 in beef steers fed 1% LA- or HA-treated corn. The 1% LA treatment decreased the concentrations of plasma LPS, LPS-binding protein and tumour necrosis factor-alpha and the relative abundance of L-phenylalanine, DL-3-phenyllactic acid and tyramine in plasma. The 1% HA treatment decreased the relative abundance of urea in plasma and increased the relative abundance of all amino acids in the plasma. CONCLUSIONS: These findings indicated that LA or HA treatment of corn modulated the degradation characteristics of starch, which contributed to improving the rumen and plasma metabolic profiles and to decreasing inflammatory responses in beef steers fed a high-concentrate diet.

Impact of acid hydrolysis and esterification process in rice and potato starch properties.

The modification of the starches aims to change the properties of these polymers making them more suitable for specific applications. Therefore, the objective of this study was to modify potato and rice starch using the hydrolysis process with hydrochloric acid (HCl) and the esterification process with citric acid (CA), both acids at different concentrations and reaction time. To verify if the modifications were effective, the physicochemical changes (solubility, swelling power, gel strength and amylose content), thermal, morphological and pasting properties were evaluated. The applied modifications reduced the swelling power, solubility and amylose content of starches. The strength of the gel was reduced with the modifications for the rice starch and increased for the potato starch. Regarding the pasting properties, modified starch RS1 (modified rice starch using 0.1 M HCl) and PS3 (modified potato starch using 2% CA) showed a tendency to reduce retrogradation. Structurally, X-ray evaluation indicated reduced crystallinity. Thermal analyses showed that gelatinization temperatures were increased for all treatments, while gelatinization enthalpies were reduced indicating greater thermal stability of the modified starches. Therefore, modified starches have distinct characteristics that can be used for specific processes that requiring starches with different properties from the conventional ones.

Saliva with reduced calcium and phosphorous concentrations: Effect on erosion dental lesions.

OBJECTIVES: To investigate whether saliva formulations with reduced calcium (Ca) and inorganic phosphorous (Pi) concentration would affect dental erosion caused by hydrochloric acid (HCl). METHODS: Enamel and root dentine bovine slabs were embedded, polished, and measured for surface Knoop microhardness (SMH). After reference areas were created, specimens were exposed to HCl solution (0.01 M; pH 2; 120 s) and immersed in artificial salivas (6 hr) containing three different Ca/Pi concentrations (n = 15), which simulate serum conditions of normo-, mild, or severe hypocalcemia. The control group was immersed in Ca/Pi-free saliva. The study protocol was carried out 2×/day for 5 days. Surface loss of enamel and root dentine was assessed using an optical profilometer, and SMH was remeasured for enamel. RESULTS: One-way analysis of variance (p < .001) and Tukey's test showed that enamel loss in groups subjected to artificial salivas that simulated mild or severe hypocalcemia did not differ from that resembling normocalcemia. %SMH was lower when saliva was mildly and normally concentrated in Ca/Pi (p < .001). Root dentine loss was higher in saliva simulating severe hypocalcemia than in those referring to mild, hypo-, and normocalcemia. CONCLUSIONS: Depending on the dental substrate, salivary formulations resembling serum hypocalcemia affected surface loss due to erosion and rehardening thereof.

Enhanced removal of Se(VI) from water via pre-corrosion of zero-valent iron using H2O2/HCl: Effect of solution chemistry and mechanism investigation.

Although the removal of Se(VI) from water by using zero-valent iron (ZVI) is a promising method, passivation of ZVI severely inhibits its performance. To overcome such issue, we proposed an efficient technique to enhance Se(VI) removal via pre-corrosion of ZVI with H2O2/HCl in a short time (15 min). The resultant pcZVI suspension was weakly acidic (pH 4.56) and contained abundant aqueous Fe2+. 57Fe Mössbauer spectroscopy showed that pcZVI mainly consisted of Fe0 (66.2%), hydrated ferric oxide (26.3%), and Fe3O4 (7.5%). Efficient removal of Se(VI) from sulfate-rich solution was achieved by pcZVI compared with ZVI (in the absence and presence of H2O2) and acid-pretreated ZVI. Moreover, the efficient removal of Se(VI) by pcZVI sustained over a broad pH range (3-9) due to its strong buffering power. The presence of chloride, carbonate, nitrate, and common cations (Na+, K+, Ca2+, and Mg2+) posed negligible influence on the removal of Se(VI) by pcZVI, while the inhibitory effect induced by sulfate, silicate, and phosphate indicated the significance of Se(VI) adsorption as a prerequisite step for its removal. The consumption of aqueous Fe2+ was associated with Se(VI) removal, and X-ray absorption near edge structure revealed that the main pathway for Se(VI) removal by pcZVI was a stepwise reduction of Se(VI) to Se(IV) and then Se0 as the dominant final state (78.2%). Moreover, higher electron selectivity of pcZVI was attributed to the enhanced enrichment of Se oxyanions prior to their reduction.

Removal of fluoride from wastewater using HCl-treated activated alumina in a ribbed hydrocyclone separator.

Excessive fluoride concentration in wastewater is a major health concern worldwide. The main objective of wastewater treatment is to allow industrial effluents to be disposed of without danger to the human health and the natural environment. In this current study, experiments have been conducted to remove fluoride from aqueous solution using alumina and HCl (Hydrochloric acid) treated activated alumina in a continuous mode. A spiral rib was introduced in the cylindrical part of the conventional hydrocyclone to increase the performance, and the new hydrocyclone is dubbed as ribbed hydrocyclone. Experiments were carried out to analyze the performance of the ribbed hydrocyclone and compared the results with the conventional hydrocyclone of the same dimension. The efficiency of conventional and ribbed hydrocyclone at a slurry flow rate of 50 LPM (liter per minute) for the solid concentration of 1.4 wt% were 80% and 93.5% respectively. The cut size d50 of the conventional and ribbed hydrocyclone was 18 µm and 13 µm respectively at a slurry velocity of 50 LPM. Fluoride removal efficiency using alumina and HCl-treated alumina was also investigated in a continuous mode by the ribbed hydrocyclone. Maximum fluoride removal efficiency was 49.5%, and 80% for alumina and HCl-treated alumina for the initial concentration of 10 mg/L at a slurry flow rate of 50 LPM.