Bittern (salt)

Last updated
Bitterns can be produced from salt ponds which get their color from organisms adapted to the hypersaline environment. Salt pond 01.jpg
Bitterns can be produced from salt ponds which get their color from organisms adapted to the hypersaline environment.

Bittern (pl. bitterns), or nigari, is the salt solution formed when halite (table salt) precipitates from seawater or brines. Bitterns contain magnesium, calcium, and potassium ions as well as chloride, sulfate, iodide, and other ions. [2] [3]

Contents

Bittern is commonly formed in salt ponds where the evaporation of water prompts the precipitation of halite. These salt ponds can be part of a salt-producing industrial facility, or they can be used as a waste storage location for brines produced in desalination processes. [3]

Bittern is a source of many useful salts. [3] [4] It is used as a natural source of Mg2+, and it can be used as a coagulant both in the production of tofu [5] and in the treatment of industrial wastewater. [6] [7] [8] [9]

History

Bittern has been extracted for a long time, at least several centuries. The Dutch chemist Petrus Jacobus Kipp (1808–1864) experimented with saturated solutions of bittern. The term for the solution is a modification of "bitter". [2]

Uses

Salt derivation

Bittern is a source of many salts including magnesium sulfate (epsom salt). Multiple methods exist for removing these salts from the bittern, and the method ultimately used depends on the target product. Products that would naturally precipitate from the bitterns crystallize as evaporation proceeds (e. g. kainite [10] ). Products that do not preferentially precipitate from bitterns may precipitate through the addition of another compound or through ion exchange. [3]

Potassium-magnesium sulfate double salt, a good fertilizer, is a salt that precipitates from bitterns upon addition of methanol. [3] Ethanol is also used, but it exhibits a preference for potassium sulfate precipitation. [3]

The solution can furthermore be used in the production of potash and potassium salts. [10] Tartaric acid is one compound that can facilitate the precipitation of these salts. [10]

Magnesium hydroxide (Mg(OH)2) can be derived from bittern. [4] Adding an alkaline solution such as sodium hydroxide (NaOH) or lime will cause magnesium hydroxide to precipitate, although lime is not as effective. Slower addition of the alkaline solution results in the precipitation of larger particles that are easier to remove from solution. [4]

Bittern is one coagulant used in the production of tofu. Tofu 3.jpg
Bittern is one coagulant used in the production of tofu.

Coagulation

Tofu

Nigari is produced from seawater after first removing sodium chloride. It contains mostly magnesium chloride, smaller amounts of magnesium sulfate (Epsom salt), potassium chloride, calcium chloride, and trace amounts of other naturally occurring salts.

Nigari was the first coagulant used to make tofu in Japan. [5] It is still used today because tofu made using bittern preserves the original flavor of the soybeans used to make it. Bittern causes rapid coagulation which influences the quality of the tofu. Alternatively calcium sulfate, calcium chloride or other substances are also used. [5]

Wastewater treatment

Bittern can be used instead of aluminum-based coagulants in the treatment of wastewater produced during the fabric-dyeing process. [6] The wastewater pH is basic, which is favorable for the use of bittern. After the addition of bittern, precipitated magnesium hydroxide works as the coagulant to collect dye, solids, organic matter, and heavy metals from the wastewater before settling out of solution. [6] The sludge produced from this wastewater treatment is also easier to dispose of than sludge produced by aluminum-based coagulants because there are less restrictions surrounding the disposal of magnesium, and it may be possible to recycle the sludge as fertilizer. [6]

Bittern can also be used as a source of magnesium ions (Mg2+) for the precipitation of struvite, a useful fertilizer, from wastewater containing nitrogen and phosphorus. [7] [8] One source of useful wastewater is landfill leachate. [9] Bittern is just as good as other sources of magnesium ions at removing phosphorus from wastewater streams, but it lags behind other magnesium ion sources in terms of the removal of ammonia (a nitrogen compound). [8]

Other uses

Bittern can be used to culture Haloquadratum archaea. Haloquadratum are distinctly square-shaped and are abundant in hypersaline environments such as salt ponds. Their cultivation is necessary for understanding both their ecological function in those environments as well as their unique morphology. [11] The presence of Haloquadratum in an environment deemed inhospitable for most life has prompted closer study of these archaea.

A study has been performed exploring the use of bittern as a natural magnesium supplement used to decrease cholesterol spikes after a meal (postprandial hyperlipidemia). [12]

Due to its high salinity, bittern can also be used as a draw solution for an osmotic process that concentrates sucrose in sugarcane juice. [13] Because forward osmosis is being used, the process is relatively energy-efficient. Epsom salt can also be taken from the bittern draw solution once it is used. [13] This method is particularly useful in areas where sugarcane and salt production are in close proximity to avoid costs associated with movement of either the sugarcane juice or the bittern. [13]

Environmental impact

In some jurisdictions, most bitterns are used for other production instead of being directly discarded. [14] In other jurisdictions each tonne of salt produced can create 3+ tonnes of waste bitterns. [15]

Although bittern generally contains the same compounds as seawater, it is much more concentrated than seawater. If bittern is released directly into seawater, the ensuing salinity increase may harm marine life around the point of release. [14] Even small increases in salinity can disrupt marine species' osmotic balances, which may result in the death of the organism in some cases. [16]

In December 1997, 94 corpses of green sea turtles, Chelonia mydas , were found at the Ojo de Liebre Lagoon (OLL) in Mexico, adjacent to the industrial operation of Exportadora de Sal S.A. (ESSA), the largest saltworks in the world. The fluoride ion F content in bitterns was 60.5-fold more than that in seawater. The bitterns osmolality was 11,000 mosm/kg of water, whereas the turtle's plasma osmolality was about 400 mosm/kg of water. Researchers concluded that the dumping of bitterns into the ocean should be avoided. [17]

The lack of adequate disposal methods for bitterns and concerns of local commercial and recreational fishing associations about bitterns’ deleterious impacts upon local fish and prawn hatchery areas led the Western Australian EPA in 2008 to recommend against the proposed 4.2 million tonne per annum Straits Salt project in The Pilbara region of WA. The EPA concluded that:

...the proposed solar salt farm is located in an area that presents unacceptably high risks of environmental harm to wetland values and unacceptable levels of uncertainty in relation to long term management of bitterns. [...] A high level of uncertainty in relation to the proponent’s ability to manage the ongoing production of over 1 million cubic metres per annum of bitterns C, which is toxic to marine biota and therefore likely to degrade wetland and biodiversity values should bitterns discharge occur either accidentally or be required to maintain salt farm production in the long term. [18]

Related Research Articles

<span class="mw-page-title-main">Lithium carbonate</span> Chemical compound

Lithium carbonate is an inorganic compound, the lithium salt of carbonic acid with the formula Li
2
CO
3
. This white salt is widely used in processing metal oxides. It is on the World Health Organization's List of Essential Medicines for its efficacy in the treatment of mood disorders such as bipolar disorder.

<span class="mw-page-title-main">Salt (chemistry)</span> Chemical compound involving ionic bonding

In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions (cations) and negatively charged ions (anions), which results in a compound with no net electric charge. The constituent ions are held together by electrostatic forces termed ionic bonds.

The term chloride refers to a compound or molecule that contains either a chlorine ion, which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond. Many inorganic chlorides are salts. Many organic compounds are chlorides. The pronunciation of the word "chloride" is.

<span class="mw-page-title-main">Brine</span> Concentrated solution of salt in water

Brine is water with a high-concentration solution of salt. In diverse contexts, brine may refer to the salt solutions ranging from about 3.5% up to about 26%. Brine forms naturally due to evaporation of ground saline water but it is also generated in the mining of sodium chloride. Brine is used for food processing and cooking, for de-icing of roads and other structures, and in a number of technological processes. It is also a by-product of many industrial processes, such as desalination, so it requires wastewater treatment for proper disposal or further utilization.

<span class="mw-page-title-main">Magnesium hydroxide</span> Inorganic compound of formula Mg(OH)2

Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (Ksp = 5.61×10−12). Magnesium hydroxide is a common component of antacids, such as milk of magnesia.

<span class="mw-page-title-main">Magnesium sulfate</span> Chemical compound with formula MgSO4

Magnesium sulfate or magnesium sulphate is a chemical compound, a salt with the formula MgSO4, consisting of magnesium cations Mg2+ (20.19% by mass) and sulfate anions SO2−4. It is a white crystalline solid, soluble in water but not in ethanol.

<span class="mw-page-title-main">Precipitation (chemistry)</span> Chemical process leading to the settling of an insoluble solid from a solution

In an aqueous solution, precipitation is the "sedimentation of a solid material from a liquid solution". The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant.

<span class="mw-page-title-main">Magnesium chloride</span> Inorganic salt: MgCl2 and its hydrates

Magnesium chloride is an inorganic compound with the formula MgCl2. It forms hydrates MgCl2·nH2O, where n can range from 1 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.

Aluminium chlorohydrate is a group of water-soluble, specific aluminium salts having the general formula AlnCl3nm(OH)m. It is used in cosmetics as an antiperspirant and as a coagulant in water purification.

<span class="mw-page-title-main">Barium chloride</span> Chemical compound

Barium chloride is an inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like most other water-soluble barium salts, it is a white powder, highly toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting to the dihydrate BaCl2·2H2O, which are colourless crystals with a bitter salty taste. It has limited use in the laboratory and industry.

<span class="mw-page-title-main">Water softening</span> Removing positive ions from hard water

Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing by reducing or eliminating scale build-up in pipes and fittings. Water softening is usually achieved using lime softening or ion-exchange resins, but is increasingly being accomplished using nanofiltration or reverse osmosis membranes.

<span class="mw-page-title-main">Calcium nitrate</span> Chemical compound

Calcium nitrate are inorganic compounds with the formula Ca(NO3)2(H2O)x. The anhydrous compound, which is rarely encountered, absorbs moisture from the air to give the tetrahydrate. Both anhydrous and hydrated forms are colourless salts. Hydrated calcium nitrate, also called Norgessalpeter (Norwegian salpeter), is mainly used as a component in fertilizers, but it has other applications. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns. A variety of related salts are known including calcium ammonium nitrate decahydrate and calcium potassium nitrate decahydrate.

<span class="mw-page-title-main">Silver chromate</span> Chemical compound

Silver chromate is an inorganic compound with formula Ag2CrO4 which appears as distinctively coloured brown-red crystals. The compound is insoluble and its precipitation is indicative of the reaction between soluble chromate and silver precursor salts (commonly potassium/sodium chromate with silver nitrate). This reaction is important for two uses in the laboratory: in analytical chemistry it constitutes the basis for the Mohr method of argentometry, whereas in neuroscience it is used in the Golgi method of staining neurons for microscopy.

Friedel's salt is an anion exchanger mineral belonging to the family of the layered double hydroxides (LDHs). It has affinity for anions as chloride and iodide and is capable of retaining them to a certain extent in its crystallographical structure.

<span class="mw-page-title-main">Uranyl carbonate</span> Chemical compound

Uranyl carbonate refers to the inorganic compound with the formula UO2CO3. Also known by its mineral name rutherfordine, this material consists of uranyl (UO22+) and carbonate (CO32-). Like most uranyl salts, the compound is a polymeric, each uranium(VI) center being bonded to eight O atoms. Hydrolysis products of rutherfordine are also found in both the mineral and organic fractions of coal and its fly ash and is the main component of uranium in mine tailing seepage water.

<span class="mw-page-title-main">Tofu</span> Soy-based food used as a protein source

Tofu is a food prepared by coagulating soy milk and then pressing the resulting curds into solid white blocks of varying softness: silken, soft, firm, extra firm. Tofu is also known as bean curd in English. Tofu originated in China and has been consumed in the country for over 2,000 years. Tofu is a traditional component of many East Asian and Southeast Asian cuisines. In modern Western cooking, it is often used as a meat substitute.

Magnesium salts are available as a medication in a number of formulations. They are used to treat magnesium deficiency, low blood magnesium, eclampsia, and several other conditions. Magnesium is an essential nutrient.

Chemical phosphorus removal is a wastewater treatment method, where phosphorus is removed using salts of aluminum, iron, or calcium. Phosphate forms precipitates with the metal ions and is removed together with the sludge in the separation unit.

Cement hydration and strength development mainly depend on two silicate phases: tricalcium silicate (C3S) (alite), and dicalcium silicate (C2S) (belite). Upon hydration, the main reaction products are calcium silicate hydrates (C-S-H) and calcium hydroxide Ca(OH)2, written as CH in the cement chemist notation. C-S-H is the phase playing the role of the glue in the cement hardened paste and responsible of its cohesion. Cement also contains two aluminate phases: C3A and C4AF, respectively the tricalcium aluminate and the tetracalcium aluminoferrite. C3A hydration products are AFm, calcium aluminoferrite monosulfate, and ettringite, a calcium aluminoferrite trisulfate (AFt). C4AF hydrates as hydrogarnet and ferrous ettringite.

<span class="mw-page-title-main">Leonite</span> Hydrated double sulfate of magnesium and potassium

Leonite is a hydrated double sulfate of magnesium and potassium. It has the formula K2SO4·MgSO4·4H2O. The mineral was named after Leo Strippelmann, who was director of the salt works at Westeregeln in Germany. The mineral is part of the blodite group of hydrated double sulfate minerals.

References

  1. Oren, Aharon (2019-01-01), Seckbach, Joseph; Rampelotto, Pabulo (eds.), "Chapter 3 - Solar salterns as model systems for the study of halophilic microorganisms in their natural environments", Model Ecosystems in Extreme Environments, Astrobiology Exploring Life on Earth and Beyond, Academic Press, pp. 41–56, doi:10.1016/b978-0-12-812742-1.00003-9, ISBN   9780128127421, S2CID   198855581 , retrieved 2019-09-23
  2. 1 2 "Bittern - Chemistry". Encyclopædia Britannica . Retrieved 4 November 2015.
  3. 1 2 3 4 5 6 Lozano, José A. Fernández (1976). "Recovery of Potassium Magnesium Sulfate Double Salt from Seawater Bittern". Industrial & Engineering Chemistry Process Design and Development. 15 (3): 445–449. doi:10.1021/i260059a018. ISSN   0196-4305.
  4. 1 2 3 Alamdari, A.; Rahimpour, M. R.; Esfandiari, N.; Nourafkan, E. (2008). "Kinetics of magnesium hydroxide precipitation from sea bittern". Chemical Engineering and Processing: Process Intensification. 47 (2): 215–221. doi:10.1016/j.cep.2007.02.012. ISSN   0255-2701.
  5. 1 2 3 Li, Jinlong; Cheng, Yongqiang; Tatsumi, Eizo; Saito, Masayoshi; Yin, Lijun (2014). "The use of W/O/W controlled-release coagulants to improve the quality of bittern-solidified tofu". Food Hydrocolloids. 35: 627–635. doi:10.1016/j.foodhyd.2013.08.002. ISSN   0268-005X.
  6. 1 2 3 4 Albuquerque, L. F.; Salgueiro, A. A.; Melo, J. L. de S.; Chiavone-Filho, O. (2013). "Coagulation of indigo blue present in dyeing wastewater using a residual bittern". Separation and Purification Technology. 104: 246–249. doi:10.1016/j.seppur.2012.12.005. ISSN   1383-5866.
  7. 1 2 Kumar, Ramesh; Pal, Parimal (2015). "Assessing the feasibility of N and P recovery by struvite precipitation from nutrient-rich wastewater: a review". Environmental Science and Pollution Research. 22 (22): 17453–17464. doi:10.1007/s11356-015-5450-2. ISSN   1614-7499. PMID   26408116. S2CID   6705389.
  8. 1 2 3 Lee, S. I; Weon, S. Y; Lee, C. W; Koopman, B (2003). "Removal of nitrogen and phosphate from wastewater by addition of bittern". Chemosphere. 51 (4): 265–271. Bibcode:2003Chmsp..51..265L. doi:10.1016/S0045-6535(02)00807-X. ISSN   0045-6535. PMID   12604078.
  9. 1 2 Li, X. Z.; Zhao, Q. L. (2002). "MAP Precipitation from Landfill Leachate and Seawater Bittern Waste". Environmental Technology. 23 (9): 989–1000. doi:10.1080/09593332308618348. hdl: 10397/2444 . ISSN   0959-3330. PMID   12361384. S2CID   24126386.
  10. 1 2 3 Ghara, Krishna Kanta; Korat, Nikunja; Bhalodia, Dixita; Solanki, Jignesh; Maiti, Pratyush; Ghosh, Pushpito K. (2014). "Production of pure potassium salts directly from sea bittern employing tartaric acid as a benign and recyclable K+ precipitant". RSC Advances. 4 (65): 34706–34711. Bibcode:2014RSCAd...434706G. doi:10.1039/C4RA04360J. ISSN   2046-2069.
  11. Bolhuis, Henk; Poele, Evelien M. te; Rodriguez‐Valera, Francisco (2004). "Isolation and cultivation of Walsby's square archaeon". Environmental Microbiology. 6 (12): 1287–1291. doi:10.1111/j.1462-2920.2004.00692.x. ISSN   1462-2920. PMID   15560825.
  12. Kishimoto, Yoshimi; Tani, Mariko; Uto-Kondo, Harumi; Saita, Emi; Iizuka, Maki; Sone, Hirohito; Yokota, Kuninobu; Kondo, Kazuo (2010). "Effects of magnesium on postprandial serum lipid responses in healthy human subjects". British Journal of Nutrition. 103 (4): 469–472. doi: 10.1017/S0007114509992716 . ISSN   1475-2662. PMID   19941679.
  13. 1 2 3 Mondal, Dibyendu; Nataraj, Sanna Kotrappanavar; Reddy, Alamaru Venkata Rami; Ghara, Krishna K.; Maiti, Pratyush; Upadhyay, Sumesh C.; Ghosh, Pushpito K. (2015). "Four-fold concentration of sucrose in sugarcane juice through energy efficient forward osmosis using sea bittern as draw solution". RSC Advances. 5 (23): 17872–17878. Bibcode:2015RSCAd...517872M. doi:10.1039/C5RA00617A. ISSN   2046-2069.
  14. 1 2 Ahmad, Nadeem; Baddour, Raouf E. (2014). "A review of sources, effects, disposal methods, and regulations of brine into marine environments". Ocean & Coastal Management. 87: 1–7. Bibcode:2014OCM....87....1A. doi:10.1016/j.ocecoaman.2013.10.020. ISSN   0964-5691.
  15. Tovar, Luis Raúl; Gutiérrez, Ma. Eugenia; Cruz, Guillermo (October 2002). "Fluoride Content by Ion Chromatography Using a Suppressed Conductivity Detector and Osmolality of Bitterns Discharged into the Pacific Ocean from a Saltworks: Feasible Causal Agents in the Mortality of Green Turtles (Chelonia mydas) in the Ojo de Liebre lagoon, Baja California Sur, Mexico". Analytical Sciences. 18 (9): 1003–7. doi:10.2116/analsci.18.1003. PMID   12243394 . Retrieved 2022-04-10.
  16. Einav, Rachel; Harussi, Kobi; Perry, Dan (2003). "The footprint of the desalination processes on the environment". Desalination. 152 (1): 141–154. doi:10.1016/S0011-9164(02)01057-3. ISSN   0011-9164.
  17. Tovar, Luis Raúl; Gutiérrez, Ma Eugenia; Cruz, Guillermo (April 3, 2002). "Fluoride Content by Ion Chromatography Using a Suppressed Conductivity Detector and Osmolality of Bitterns Discharged into the Pacific Ocean from a Saltworks: Feasible Causal Agents in the Mortality of Green Turtles (Chelonia mydas) in the Ojo de Liebre lagoon, Baja California Sur, Mexico". Analytical Sciences. 18 (9): 1003–1007. doi:10.2116/analsci.18.1003. PMID   12243394 via J-Stage.
  18. "Yannarie Solar Salt East Coast of Exmouth Gulf" (PDF). Environmental Protection Authority. July 2008. Retrieved 21 December 2019.