A research team at the Faculty of Engineering, Universitas Negeri Malang (FT UM) has found that a solvent's capacity to form hydrogen bonds determines the outcome of wet grinding scallop shell powder, according to Kompasiana.com. The same property tracks with how finely the calcium carbonate crystals are reduced and with how much the grinding media wear down. The work was reported on 7 November 2026 from Malang.
The study was led by Diki Dwi Pramono, a lecturer in FT UM's Department of Mechanical and Industrial Engineering, and funded under the faculty's 2026 early-career lecturer research scheme. Scallop shells (Amusium pleuronectes) are between 98 and 99 percent calcium carbonate by weight, yet most are discarded. Wet milling offers a route to turning them into a fine powder with added value.
Why it matters
Solvent choice for wet grinding is usually framed in simple terms: polar or nonpolar. The UM data suggest that framing misses the variable that actually orders the results. If hydrogen bonding is the controlling factor, it gives researchers a measurable basis for picking a liquid rather than a rough category.
The finding carries a practical trade-off as well. Water is cheap and safe, but in this study it also caused the heaviest wear on the milling media — material that ends up mixed into the product.
Four solvents, one milling protocol
The team ground shell powder in four liquids: deionized water, ethanol, dimethylformamide (DMF) and n-hexane. Every sample went through the same planetary ball mill at 500 rpm for 20 hours, with unmilled powder kept as a reference. Analysis used X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and particle size and zeta potential measurements.
The calcite structure survived in every solvent. No aragonite or other phase formed. What changed was crystallite size, which fell from 44.7 nm to between 28.2 and 35.7 nm after grinding in water, ethanol and DMF.
The refinement sequence followed the Hansen hydrogen-bonding parameter (H) of each solvent. Moving from water (H 42.3 MPa) to ethanol (19.4 MPa) and then DMF (11.3 MPa), the diffraction peak width of calcite (104) — a marker of finer crystals — rose from 0.230 to 0.262 and 0.291. Of six solvent properties tested, only H produced this ordering; permittivity, surface tension and viscosity did not.
"Until now, solvents for wet grinding have usually been chosen based on polar or nonpolar categories. Our data show that what orders the results is actually the solvent's ability to form hydrogen bonds," Diki said, as quoted by Kompasiana.com.
Media wear follows the same order
The same sequence appeared in wear on the grinding equipment. EDX estimates put alumina and zirconia fragments from the balls and jar at up to 65 percent by weight in the water sample, 53 percent in ethanol and 34 percent in DMF. Because EDX reads only particle surfaces, these figures are semiquantitative.
The n-hexane sample showed the largest peak broadening (0.484), but the jar's silicone seal degraded in that solvent. About 3 percent by weight of PDMS from the seal carried over into the powder, so the sample was analyzed separately.
"Water is indeed cheap and safe, but in this study water also eroded the grinding media the most. Solvent selection has to weigh hydrogen bonding, media wear and compatibility with equipment seals," Diki said.
The team notes that with the three clean solvents, the influence of the liquid and the influence of wear fragments could not yet be separated. Next steps are an acid-insoluble residue test to measure fragments across the board, plus a series of grinding-time variations in water and DMF.
The calcium carbonate powder from scallop shells also serves as raw material for the group's research into nano-hydroxyapatite and vegetable-oil lubricant additives. A manuscript from this study is being prepared for publication in a reputable international journal.
The research team comprises Diki Dwi Pramono, Prof. Poppy Puspitasari, Yahya Zakaria, Avita Ayu Permanasari and Alief Muhammad of the Department of Mechanical and Industrial Engineering, along with Jibril Maulana of UM's Faculty of Vocational Studies. Alief Muhammad is also affiliated with Universitas Panca Marga in Probolinggo.
Watch for the acid-insoluble residue results and the grinding-time series, which should show whether the solvent effect holds once wear debris is fully accounted for.
