CHANGELOG.md

pyEQL Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[1.4.0] - 2026-02-17

Added

• Phreeqc2026EOS: Brand new, custom-compiled wrapper that interfaces directly with IPHREEQC modules distributed by USGS. This new PHREEQC interface is accessible via the new phreeqc2026 electrolyte modeling engine, and will be used by default in the native engine in v1.5.0. (#306, #318, #318, #319, #333, # @vineetbansal)
• Solution.from_preset: Added presets for 22 representative industrial wastewater compositions, explained in detail in our recent preprint "Composition and Critical Mineral Content of Major Industrial Wastewaters: Implications for Treatment and Resource Recovery Technologies," available at [https://www.researchsquare.com/article/rs-8743330/v2]

Changed

• Solution.equilibrate: Added support for solid-liquid and gas-liquid equilibrium via three new kwargs - atmopshere, solids, and gases. See docstring for details and usage.(#292, #294, #339, @vineetbansal, @YitongPan1, @SuixiongTay)
• get_components_by_element: A new keyword argument nested was added to methods get_components_by_element and get_el_amt_dict of the Solution class. It defaults to False (no change from prior behavior), but can be set to True to return a 2-level dictionary, with the element symbol as the key at the top level, and the valence (float, or "unk" for unknown) as the key at the second level. This should make it easier for future code to calculate the total amount of a given element regardless of its valence. (#284, @vineetbansal)
• Solution.get_property: Changed the lru_cache size to greatly enhance performance when creating Solution that contain a large number of solutes (@vineetbansal, @SuixiongTay)
• Docs: sphinx-material theme migrated to sphinx-immaterial (#272, @ugognw, @rkingsbury)
• Docs: resolved all the spinx build warnings and errors (#338, @vineetbansal)
• Docs: Added documentation of phreeqc2026 engine and new equilibrate features (#344, #349, @SuixiongTay, @YitongPan1)
• CI: Various changes to optimize our continuous integration testing workflows. Notably, changes to the docs (only) no longer trigger unit tests of the code (only of the docs), and now test against a specific set of pinned dependencies from requirements.txt. (#285, #314, #320, #327, #328, #330, #340, @vineetbansal, @rkingsbury)

Fixed

• NativeEOS equilibrate: Fixed a bug in which instantiating a solution with pure elements (e.g., {'Na': '0.5 mol/L'}) and then calling equilibrate could cause that element to be "double counted." In other words, speciation calculations would add Na[+1] to the solution but retain Na as well. This now works correctly. In addition, elements or species that are missing from PHREEQC's database (e.g. Rh) are handled more robustly. (#282, #352, #355, @vineetbansal, @rkingsbury)
• from_file: Instantiating a Solution from a .yaml file now gives slightly more accurate results. Previously, there were slight discrepancies in the volume of the loaded solution, compared to loading from .json or dict. (#347, @rkingsbury)
• standardize_formula: Fixed incorrect reduction of dimers. For example, (CO2)2 was being standardized to CO2, which could cause incorrect concentrations to be reported. Dimers are no longer reduced. (#309, @vineetbansal)
• FormulaDict: ensured that quantities are always represented by python floats and not np.float64 (#342, @rkingsbury)

[1.3.2] - 2025-09-15

Fixed

• Solution.get_viscosity_kinematic(): A recent change to get_salt_dict (#258) created a problem with get_viscosity_kinetmatic in which an empty solution would cause the method to return an error. This has been fixed, and unit tests added for both get_viscosity_kinematic and get_viscosity_dynamic.

[1.3.1] - 2025-08-18

Fixed

• Solution.get_salt_dict(): In solutions containing polyatomic ions with a heteroatom (an atom other than H or O) having a stoichiometric coefficient greater than 1 mol per mol salt , such as Fe(CN)6[-3], the method would return incorrect results, possibly impacting activity coefficient calculations. This has now been fixed. (#277, @ugognw)

[1.3.0] - 2025-08-08

Fixed

• Solution.__add__: engine, solvent, database were not inherited by the sum of Solution objects (#258, @ugognw)
• Solution.get_activity_coefficient: Fixed bugs where incorrect Pitzer scaling parameters $\alpha_1$ and $\alpha_2$ parameters were used to calculate activity coefficients and solute molar volumes for salts with multivalent ions (#258, @ugognw)
• Solution.get_salt_dict: fixed errors in the calculation of concentrations for salts containing polyvalent cations (#258, @ugognw)
• Solution.get_salt_dict now respects the cutoff parameter. Note that cutoff is now interpreted in units of moles per kilogram of solution (#258, @ugognw)
• Solution.get_salt_dict always returns a salt dictionary sorted in order of decreasing salt concentration (#258, @ugognw)
• Solution.__init__: Raise ValueError if a user sets inconsistent H[+1] in solutes and pH keyword arguments (#270, @gnuhpdiem, @rkingsbury). Previously, if the user set H[+1] in solutes, it's value would silently override the pH kwarg. Now, you will get a ValueError if the two are inconsistent, unless the pH kwarg is kept at the default value. In that case, a warning will be logged.
• standardize_formula: properly interpret ambiguous dash / hyphen characters as "minus" (#264, @rkingsbury)
• Ensure Solution.p() always returns a regular float and returns np.nan if the concentration is zero or negative (#269, @rkingsbury)
• Solution.get_diffusion_coefficient: prevent diffusion coefficient adjustment when temperature is within 1 degree of the the reference value (#215, @YitongPan1)
• Tests: literature data used in test_mixed_electrolyte_activity.py was updated to reflect corrected we recently became aware of. (#271, @Ouriel-N, @rkingsbury)
• Docs: Sphinx warnings are cleared (#255, ugognw)
• Docs: Minor fixes for private / cached methods (#197, @githubalexliu)
• Docs: Edit documentation of debye_parameter_B (#196, @YitongPan1)

Added

• Docs/CI: sphinx linkcheck job and tox environment/command (tox -e links) (#255, @ugognw)
• Docs: add carbonate system tutorial (#204, @NikhilDhruv)

Changed

• BREAKING - the return value of Solution.get_salt_dict now includes Salt objects instead of keys corresponding to cation and anion. See the example in the docstring for how to adapt existing code to accommodate this change. (#258, @ugognw)
• BREAKING - Solution.get_salt_dict no longer returns an entry for water (#258, @ugognw)
• BREAKING - Solution.get_salt will not return water and may return None if no salt is present. Previously, Solution.get_salt would have returned a Salt representing water. (#258, @ugognw)
• Ensure more consistent column formatting in Solution.print() (#269, @rkingsbury)
• Switch math.log10 to np.log10 in Solution.p() (#269, @rkingsbury)
• update pre-commit configuration (#269, @rkingsbury)
• use --dist loadscope in parallelized CI tests. Closes #170. (#269, @rkingsbury)
• update license specification in pyproject.toml to conform to latest packaging standards. Closes #233. (#269, @rkingsbury)
• add py.typed to report type checking to other libraries. Closes #179. (#269, @rkingsbury)
• Support numpy>2.0
• Bump pint to 0.24.4 for numpy v2.0 compatibility and to mitigate CI issues (#239, @SuixiongTay, @rkingsbury)
• CI: add python v3.13 to post-merge unit tests
• Docs: tox -e docs command configured to fail on warning (#255, ugognw)
• Docs: ReadTheDocs built with Python 3.11 (#255, ugognw)
• Use importlib to locate test files (#241, @SuixiongTay)
• Support numpy>2.0
• Bump pint to 0.24.4 for numpy v2.0 compatibility and to mitigate CI issues (#239, @SuixiongTay, @rkingsbury)
• CI: add python v3.13 to post-merge unit tests
• bump pymatgen to v2025.1.9
• bump maggma to v0.71.4

Removed

• BREAKING Methods previously marked for deprecation - list_solutes, list_activities, list_concentrations, list_salts have been removed.
• Solution.add_solvent has been marked for deprecation and will be removed in a future release. Use add_solute instead.
• Python 3.9 version classifier in pyproject.toml (#247, @ugognw)
• Solution.list_salts (use Solution.get_salt_dict() instead) (#258)

[1.2.0] - 2024-09-24

Fixed

• Database: removed several erroneous species (such as CO32- which was really CO3[-2]), corrected other parsing errors, and updated formula syntax for consistency with recent standardize_formula changes (e.g., H4NCl -> NH4Cl) (#190, @rkingsbury)

Changed

• Bump pymatgen to v2024.9.10 for additional upstream formula fixes. (#188, @abhardwaj73)

Removed

• BREAKING - dropped python 3.9 support, in accordance with numpy deprecation policy. (#188, @abhardwaj73)

[1.1.6] - 2024-09-01

Fixed

• Solution.get_total_amount: Bugfix that caused an error when called on certain elements without specifying an oxidation state. For example, get_total_amount('N') could raise an exception in a solution containing Na (but no N) due to a flaw in a logical test.
• Solution._adjust_charge_balance: Removed a misleading and redundant log message (#162, @SuixiongTay)

Added

• gibbs_mix: A new keyword argument activity_correction was added to gibbs_mix. It defaults to True (no change from prior behavior), but can be set to False in order to calculate the ideal mixing energy, which is equivalent to only considering entropic effects. (#178, @Jaebeom-P)
• standardize_formula: Improve formatting of ammonium sulfate salts. Aqueous ammonium sulfate previously standardized to H8S(NO2)2(aq), now it will display as (NH4)2SO4(aq).

Changed

• BREAKING entropy_mix now returns the ideal mixing entropy in units of J/K rather than the mixing energy in J. This was done to improve clarity with respect to the function name. An activity_correction kwarg was added to gibbs_mix so that you can still calculate the ideal mixing energy by setting it to False. (#178, @Jaebeom-P)
• Revise documentation of gibbs_mix, entropy_mix, and donnan_eql. (#178, @Jaebeom-P)
• CI: Improve comprehensiveness of CI dependency testing. (#163, #164, @abhardwaj73)

[1.1.5] - 2024-07-28

Fixed

• Solution: Hotfix to remove a stray assert statement in _adjust_charge_balance that would sometimes cause errors inpH charge balancing.

[1.1.4] - 2024-07-28

Fixed

• Solution: Fix a bug inpH charge balancing that erroneously prevented charge balancing from occurring in certain cases, and raised an error.

[1.1.3] - 2024-07-28

Fixed

• Solution: Fix a bug in which setting balance_charge to pH could result in negative concentration errors when charge balancing or after equilibrate was called. Solution now correctly enforces the ion product of water (Kw=1e-14) whenever adjusting the amounts of H+ or OH- for charge balancing.

Added

• Solution._adjust_charge_balance: Added a privat helper method to consolidate charge balancing code used in __init__ and equilibrate.

[1.1.2] - 2024-07-28

Fixed

• Solution: Fix a bug in which setting balance_charge to auto when the initial composition was electroneutral would cause errors and/or improper charge balancing after equilibrate was called.

[1.1.1] - 2024-07-27

Fixed

• equilibrate: Fixed a bug that could cause an AttributeError when pH was used for charge balancing.
• Database: size.radius_ionic was missing units for Ni[+2] and Cr[+3]. Correct units have been added.

Added

• Solution: New automatic charge balancing method will automatically identify the majority (highest concentration) cation or anion as appropriate (depending on the charge balance) for charge balancing. To use this mode, set balance_charge='auto' when instantiating a Solution.

Changed

• Solution.add_amount: This method will now add solutes that are absent from the Solution. Previously, calling, e.g., add_amount('Na+', '1 mol') on a Solution that did not contain any sodium would result in an error. A warning is logged if the method has to add a new solute.
• Units: use the upstream chemistry context from pint instead of the custom one from 2013.
• pre-commit autoupdate
• Misc. linting and code quality improvements.
• Unit tests: update tmpdir to tmp_path text fixture.
• CI: Small updates to pre-commit and GitHub actions per scientific python repo review.

[1.0.3] - 2024-07-20

Fixed

• standardize_formula: Fix incorrect display of additional formulas, including methane which was shown as "H4C(aq)", other tri-anions (N3-, P3-), and a variety of haloacetic acids. For example, tricholoracetic acid was previously shown as 'C2Cl3O2[-1]' but will now display as 'CCl3COO[-1]'.

Added

• standardize_formula: pyEQL can now parse ion formulas that contain unicode superscript or subscript characters, which makes input even more flexible. For example, "PO₄³⁻" and "Co²⁺" will now standardize correctly to "PO4[-3]" and "Co[+2]", respectively.

Changed

• Housekeeping: move all project configuration to pyproject.toml

[1.0.2] - 2024-07-09

Fixed

• standardize_formula: Fix incorrect display of ammonium/ammonia. Previously, their formulas were shown as "H4N[+1]" and "H3N(aq)", respectively. They now correctly display as NH4 and NH3. Similar fixes were implemented for HPO4[-2] / H2PO4[-1] / H3PO4, formate (HCOO[-1]), oxalate (C2O4[-2]), thicyanate (SCN[-1]), and triiodide (I3[-1]). Fixes #136 (@xiaoxiaozhu123)

[1.0.1] - 2024-06-17

Added

• Added NPY201 ruleset to ruff configuration to check support for numpy 2.0

Fixed

• NativeEOS and PHREEQCEOS equilibrate: Fixed a charge balancing bug that cause repeated calls to equlibrate to severely distort the pH and/or the composition. (#141)[#141]
• UnicodeDecodeError when trying to connect to ion database on non-English platforms (#122)

Changed

• Replace math with numpy functions throughout. This mainly changed calls to log and exp.
• Docs: Fix missing close parentheses in docstring (@Andrew S. Rosen)

[1.0.0] - 2024-03-17

Added

• Solution.__init__: new keyword argument log_level allows user to control the verbosity of log messages by setting the level (e.g., ERROR, WARNING, etc.) that will be shown in stdout.
• Docs: added a note about a workaround for Apple M1/M2 Macs proposed by @xiaoxiaozhu123

Changed

• Solution.__init__: The deprecated format for specifying solutes (e.g., [["Na+", "0.5 mol/L]]) which previously only generated log warning message, now raises a DeprecationWarning. Use dict-style input (e.g., {"Na+":"0.5 mol/L"}) instead.
• New logo! Updated the pyEQL logo (for the first time in 9 years!) to address an obsolete font in the .svg and modernize the design.

Removed

• BREAKING All methods and functions (with the exception of Solution.list_XXX methods) previously marked with deprecation warnings have been removed.

[0.15.1] - 2024-03-13

Fixed

• Solution.get_total_amount: Fixed an issue in which ppm units would fail.

[0.15.0] - 2024-03-13

Added

• utils.interpret_units: New method to "sanitize" environmental engineering units like ppm to strings that pint can understand, e.g. ppm -> mg/L. This method is now used in get_amount and get_total_amount to ensure consistency in how they process units.

Changed

• CI: pre-commit autoupdate

Fixed

• Solution: Fixed an issue in which repeated calls to equilibrate when using NativeEOS or PHREEQCEOS would change the mass of the Solution slightly. This was attributed to the fact that pyEQL and PHREEQC use slightly different molecular weights for water.
• Solution: get_total_amount and related methods could fail when the oxidation state of an element was unknown (e.g., 'Br') (Issue #116)

[0.14.0] - 2024-03-05

Added

• NativeEOS / PhreeqcEOS: Added try/catch so that pyEQL can still be used on platforms that PHREEQC does not support, such as Apple Silicon. In such cases, functions like equilibrate that depend on PHREEQC will raise errors, but everything else can still be used.
• CI: Added Apple M1 runner (GitHub: macos-14) to the CI tests.

Fixed

• CI: Addressed several issues in the testing configuration which had resulted in testing fewer operating systems x python version combinations than intended. CI tests now correctly and comprehensively test every supported version of python on every os (macos, windows, ubuntu).
• utils.FormulaDict: implemented __contains__ so that get() works correctly in python 3.12+. See python/cpython#105524
• Docs: fixed many small problems in documentation causing equations and examples to render incorrectly.
• Solution.from_file: Add missing @classmethod decorator; update documentation.

[0.13.0] - 2024-03-05

Fixed

• equilibrium.alpha(): Fixed incorrect calculation of acid-base distribution coefficient for multiprotic acids.

[0.12.2] - 2024-02-25

Fixed

• Solution.get_total_amount: Fix bug that would cause the method to fail if units with names not natively understood by pint (e.g., 'ppm') were passed.

[0.12.1] - 2024-02-25

Fixed

• Solute.from_formula: Fix bug in which an uncaught exception could occur when if pymatgen failed to guess the oxidation state of a solute. (Issue #103 - thanks to @xiaoxiaozhu123 for reporting).
• Solution.get_total_amount: Fix bug that would cause the method to fail if mass-based units such as mg/L or ppm were requested.

[0.12.0] - 2024-02-15

Added

• Solution: new kwarg default_diffusion_coeff which allows the user to specify a value to use when a species diffusion coefficient is missing from the database. By default, the value for NaCl salt (1.61e-9 m2/s) is used. This is important for conductivity and transport number calculations, which perform weighted summations of diffusion coefficients over every species in the solution. Previously, species with missing diffusion coefficients would be excluded from such calculations, possibly resulting in inaccuracies, particularly after calling equilibrate(), which often generates charged complexes such as NaSO4- or MgCl+.

Fixed

• Solution.__add__: Bugfix in the addition operation + that could cause problems with child classes (i.e., classes that inherit from Solution) to work improperly

Changed

• Removed deprecated pkg_resources import in favor of importlib.resources

[0.11.1] - 2023-12-23

Added

• Add tests for gibbs_mix and entropy_mix functions. Format docstrings in Google style.

Fixed

• Solution.from_preset: Fixed a packaging error that made this method fail with a FileNotFoundError.

Removed

• functions.py is no longer imported into the root namespace. You'll now need to say from pyEQL.functions import gibbs_mix instead of from pyEQL import gibbs_mix

[0.11.0] - 2023-11-20

Changed

• PhreeqcEOS: performance improvements for the phreeqc engine. The EOS instance now retains the phreeqpython solution object in between calls, only re-initializing it if the composition of the Solution has changed since the previous call.

Fixed

• equilibrate: Fixed several bugs affecting NativeEOS and PhreeqcEOS in which calling equilibrate() would mess up the charge balance. This was especially an issue if balance_charge was set to something other than pH.

Removed

• equilibrium.equilibrate_phreeqc() has been removed to reduce redundant code. All its was absorbed into NativeEOS and PhreeqcEOS

[0.10.1] - 2023-11-12

Added

• utility function create_water_substance with caching to speed up access to IAPWS instances

Changed

• Solution.get_diffusion_coefficient: the default diffusion coefficient (returned when D for a solute is not found in the database) is now adjusted for temperature and ionic strength.
• Solution.water_substance - use the IAPWS97 model instead of IAPWS95 whenever possible, for a substantial speedup.

[0.10.0] - 2023-11-12

Added

• Solution: Revamped docstrings for conductivity, get_transport_number, get_molar_conductivity, and get_diffusion_coefficient.
• Solution: new method get_diffusion_coefficient for dedicated retrieval of diffusion coefficients. This method implements an improved algorithm for temperature adjustment and a new algorithm for adjusting infinite dilution D values for ionic strengthe effects. The algorithm is identical to that implemented in PHREEQC >= 3.4.
• Database: empirical parameters for temperature and ionic strength adjustment of diffusion coefficients for 15 solutes
• Added tests for temperature and ionic strength adjustment and conductivity
• Docs: new tutorial notebooks
• Docs: remove duplicate contributing pages (Closes #68)
• Solution: new method to_file() for more convenient saving Solution object to json or yaml files. (@kirill-push)
• Solution: new method from_file() for more convenient loading Solution object from json or yaml files. (@kirill-push)
• Solution: new classmethod from_preset() to replace pyEQL.functions.autogenerate() and instantiate a solution from a preset composition. (@kirill-push)

Changed

• Solution: method af adjusting diffusion coefficients for temperature was updated (same as used in PHREEQC >= 3.4)
• Solution.conductvity: improved equation (same as used in PHREEQC >= 3.4) which is more accurate at higher concentrations

Fixed

• Database errors with Cs[+1] diffusion coefficient and KBr Pitzer parameters
• Restored filter that suppresses duplicate log messages

Deprecated

• replace pyEQL.functions.autogenerate() is now deprecated. Use from_preset instead.

Removed

• The activity_correction kwarg in get_transport_number has been removed, because this now occurs by default and is handled in get_diffusion_coefficient.

[0.9.2] - 2023-11-07

Fixed

• Restored filter that suppresses duplicate log messages

[0.9.1] - 2023-11-04

Added

• format_solutes_dict() method added into the utils module to help format solutes dictionaries with a unit. (@DhruvDuseja)

Changed

• Native property database is now instantiated on pyEQL.__init__ to speed subsequent access by Solution
• Numerous performance optimization increased the speed of many Solution property and method calls by 3x-10x

[0.9.0] - 2023-10-17

Added

• Solution.print() added to take the place of the deprecated list_xxx methods.

Changed

• Breaking pyEQL.unit deprecation machinery has been removed to quiet the warning messages on import. The pyEQL unit registry was renamed to pyEQL.ureg in v0.6.1.
• Significant documentation updates.
• Solution.components is now automatically sorted in descending order of amount, for consistency with anions, cations, and neutrals.

Removed

• Solution.list_solutes() has been removed. Use Solution.components.keys() instead.

Fixed

• Bugfix in as_dict to make serialization via dumpfn possible. Previously, Quantity were not converted to a serializable form. Now, Quantity are converted to str in as_dict().

Removed

• python 3.8 is no longer supported

[0.8.1] - 2023-10-01

Changed

• from_dict modified to avoid call to super(), making for more robust behavior if Solution is inherited.

Removed

• copy() method was removed for consistency with python conventions (it returned a deep rather than a shallow copy). Use copy.deepcopy(Solution) instead.

Fixed

• Bugfix in as_dict in which the solutes attribute was saved with Quantity rather than float
• Simplified Solution.get_conductivity to avoid errors in selected cases.
• Required pymatgen version was incorrectly set at 2022.8.10 when it should be 2023.8.10
• Bug in get_osmotic_coefficient that caused a ZeroDivisionError with an empty solution.

[0.8.0] - 2023-09-27

Added

• New electrolyte engine PhreeqcEOS provides phreeqpython activities within pyEQL
• Solution: use total element concentrations when performing salt matching (can be disabled via kwarg)
• Solution: add speciation support to the native engine via phreeqpython
• Solution: add keyword argument to enable automatic charge balancing
• Salt: class is now MSONable (i.e., serializable via as_dict / from_dict)
• Solution: new properties anions, cations, neutrals provide easy access to subsets components.
• Solution: improvements to get_total_amount.
• Solution: new function get_components_by_element that lists all species associated with elements in specific oxidation states.
• Solution: new properties elements and chemical_system, new function get_el_amt_dict to compute the total number of moles of each element present in the Solution.

Changed

• pH attribute is now calculated from the H+ concentration rather than its activity. For the old behavior, use Solution.p('H+') which defaults to applying the activity correction.
• Update test_salt_ion_match to pytest format and add additional tests
• Update test_bulk_properties to pytest format

Removed

• Solution.list_salts() has been removed. See Solution.get_salt_dict() for equivalent functionality
• salt_ion_match.generate_salt_list and identify_salt have been removed. See Solution.get_salt_dict() and Solution.get_salt() for equivalent functionality.

Fixed

• Bug in get_transport_number caused by migration to standardized solute formulas
• Scaling of salt concentrations in get_salt_dict was incorrect in some edge cases
• Disable hydrate notation in standardize_formula, which caused hydroxides such as 'Ca(OH)3' to be written 'CaO2H.H2O'
• Inconsistent formatting of oxidation states in get_total_amount and Solute
• Inconsistent return type from get_property when molar_volume and diffusion_coefficient were missing
• Two issues with the formatting of the H2O(aq) entry in the database, pyeql_db.json

[0.7.0] - 2023-08-22

Changed

• Solution now more robustly converts any user-supplied formulas into unique values using pymatgen.core.ion.Ion.reduced_formula. This means that the .components or solvent attributes may now differ slightly from whatever is entered during __init__. For example, Solution(solvent='H2O').solvent gives H2O(aq). This behavior resolved a small bug that could occur when mixing solutions. User supplied formulas passed to get_amount or Solution.components[xxx] can still be any valid formula. E.g., Solution.components["Na+"], Solution.components["Na+1"], and Solution.components["Na[+]"] will all return the same thing.

[0.6.1] - 2023-08-22

Added

• Solution: enable passing an EOS instance to the engine kwarg.
• Solution: new properties total_dissolved_solids and alias TDS
• Solution: support new units in get_amount - ppm, ppb, eq/L, etc.
• Solution: implemented arithmetic operations + (for mixing two solutions), * and \ for scaling their amounts

Changed

• pyEQL.unit was renamed to pyEQL.ureg (short for UnitRegistry) for consistency with the pint documentation and tutorials.

[v0.6.0] - 2023-08-15

Added

• Solution: add tests to confirm that solution density changes with temperature and pressure
• Solution: add tests for charge_balance, alkalinity, hardness, osmotic_pressure, p(), and conductivity
• Solution: pE attribute and kwarg
• Solution: add support for passing solutes as a dict
• Implement extensible system for connecting Solution to various activity and speciation models. Models can be integrated into pyEQL by implementing an EOS class. The desired activity model is selected on init. Currently available models are native (for pyEQL's implementation of Pitzer, which decays gracefully into Debye-Huckel and other models if parameters are not available) or ideal for a dummy engine that returns unit activity coefficients. Support for additional external engines such as phreeqpython is planned.
• Add pymatgen, monty, and maggma as dependencies
• Add pre-commit configuration
• Add pull request template, new GitHub actions, and tox -e autodocs environment to serve and update docs in real time
• Add pre-commit configuration and lint with ruff using rulesets mostly borrowed from pymatgen
• Add more comprehensive platform testing via tox

Changed

• Complete overhaul of the property database. The database is now distributed in a .json file containing serialize Solute objects. Solution can now be connected to this database (by default) or to any other maggma Store containing properly formatted data. database.py, parameter.py, and all the .tsv data files have been removed and replaced with pyeql_db.json.
• Docs: update, change theme, convert to .md format, and adopt Keep a Changelog format
• Replace water_properties.py with iapws package
• Replace elements.py`` with pymatgen.core.periodic_table`
• Solution.charge_balance now returns in equivalents instead of Coulombs
• Migrate all tests to pytest
• Update packaging format to use pyscaffold

Deprecated

• Solution: new properties pressure, temperature, volume, pH, mass, density, viscosity_dynamic, viscosity_kinematic, ionic_strength, conductivity, debye_length, bjerrum_length, alkalinity, hardness, dielectric_constant, osmotic_pressure, solvent_mass, charge_balance have replaced the corresponding get_XXX and set_XXX (for temperature and pressure) methods, which will be removed in a future release. get_viscosity_relative will be removed entirely.
• Solute: methods get_formal_charge(), get_name(), and get_molecular_weight() have been replaced by direct access to the attributes charge, formula, and mw, respectively.

Removed

• disable 'verbose' kwarg in get_activity and get_activity_coefficient

Fixed

• Fixed various documentation rendering issues
• bug in alkalinity

[0.5.2] - 2020-04-21

• Fix breaking bug introduced by upstream pint change to avogadro_number
• Format project with black
• Misc. linting and docstring changes

[0.5.0] 2018-09-19

• Implement the effective Pitzer model for improved activity calculations in multicomponent solutions
• Add support for calculation of activity and osmotic coefficients on different scales
• Add support for calculating % by weight to get_amount()
• Added methods for calculating the osmolarity or osmolality of a Solution
• Add the ability to filter list_concentrations() to show only cations or anions
• Add two medical solutions - normal saline and Ringer's lacate -to the autogenerate method
• Add shorthand abbreviations for 'seawater' and 'wastewater' in the autogenerate method
• Enhance automatic test suite to compare results with experimental data based on relative error
• Add test suites for the effective Pitzer model and a multicomponent salt solution
• DEPRECATED get_mole_fraction. Use get_amount() instead
• Fix bug causing get_activity_coefficient to fail if the solute concentration was zero

[0.4.0] 2016-07-14

• Add ability to calculate dielectric constant based on solution composition for salts
• Add database entries for the viscosity 'B' parameter for 63 more inorganic ions
• Add domestic wastewater and human urine to the autogenerate()method
• Improve entry point for running automated tests (#16, thanks Hernan Grecco)
• Significantly expand documentation of activity correction methods
• Make output of get_osmotic_coefficient more verbose when Pitzer parameters are not found
• Fix bug causing activity corrections for non 1:1 salts to be calculated incorrectly (#15)
• Fix bug causing 'bad operand type' error when calculating osmotic pressure on some systems
• Fix bug causing ValueError exceptions when a solute has zero concentration
• Numerous fixes and corrections in the documentation

[0.3.1] 2016-02-24

• Fix packaging problems preventing installation from PyPi
• Fix character encoding issue in Erying_viscosity database file

[0.3.0] 2016-01-15

• Add method to calculate the total concentration of an element in a solution
• Add method to automatically generate certain solutions (like seawater)
• Add method to calculate the hardness of a solution
• Add method to calculate the alkalinity of a solution
• Add method to calculate the charge balance of a solution
• Add method to calculate the Bjerrum length
• Add database entries for hydrated and ionic radii of 23 commonions
• Add database entries for the 'B' parameter in the Jones-Dole viscosity equation for 20 common ions
• Add test suites for solute property methods, hardness, osmotic coefficient, and Debye length
• Improve logging system to work better when using pyEQL interactively
• Improved README with graphics and rich formatting
• Fix bug related to activity and osmotic coefficients for multivalent salts
• Fix bug related to retrieval of water properties
• Documentation enhancements and fixes

[0.2.2] 2015-08-28

• Fix bug in get_amount() causing no output when mass-based units were specified.

[0.2.1] 2015-05-06

• Add 93 entries to diffusion coefficient database
• Add 93 entries to Pitzer partial molar volume parameters database
• Add 130 entries to Pitzer activity parameters database
• Change extension for database files from .csv to .tsv
• Corrections and additions to the contributing documentation
• Uploaded to the Python Package Index for easier installation
• Add this changelog

[0.2.0] 2015-03-26

• First public release