The present study deals with the adsorptive removal of Escherichia coli (E. coli) by making use chitosan-silica/calcium carbonate (CS-SiO2/CaCO3) nanocomposites (NCs) where it was synthesized using waste eggshells and rice husks occurred natural sources. bioadsorbent CS-SiO2/CaCO3 NCs were incorporating eggshell-CaCO3 nanoparticles (NPs) husk-SiO2 NPs in chitosan solution. adsorbents characteri...

In this study we present a comparative quantification of CaCO3 production rates by rhodolith-forming coralline red algal communities situated in high polar latitudes and assess which environmental parameters control these production rates. The present rhodoliths act as ecosystem engineers, and their carbonate skeletons provide an important ecological niche to a variety of benthic organisms. The...

A previously published hydrothermal brine-river water mixing model driven by ocean crust production suggests that the molar Mg/Ca ratio of seawater (mMg/Ca(sw)) has varied significantly (approximately 1.0-5.2) over Precambrian time, resulting in six intervals of aragonite-favouring seas (mMg/Ca(sw) > 2) and five intervals of calcite-favouring seas (mMg/Ca(sw) < 2) since the Late Archaean. To ev...

The structural transformation in aragonite CaCO3 is simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon-Kim modified electron gas formalism. We found two phase transitions in aragonite at high temperature.

Equations used to develop the CO2 -Ca-pH relationships in calcareous soils are reviewed. The equation Pco, (Ca) --(H) 2 Ke , is used to draw a three-dimensional surface and to derive three partial differential equations to illustrate the relationships between CO 2 partial pressure, Ca activity and pH. lc is a combination of Henry's Law constant, the first and second dissociation constants for c...

Artificial bone grafting is widely used in current orthopedic surgery for bone defect problems. Unfortunately, surgeons remain unsatisfied with the current commercially available products. One of the major complaints is that these products cannot provide sufficient mechanical strength to support the human skeletal structure. In this study, we aimed to develop a bone scaffold with better mechani...

Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold m...

The hardness-based regulatory approach for Cu prescribes an extrapolation of the toxicity-versus-hardness relationship to low hardness (< or =50 mg/L as CaCO3). Hence, the objective of the present research was to evaluate the influences of water quality on acute Cu toxicity to larval fathead minnow (Pimephales promelas) in low-hardness surface waters. Seasonal water sampling was conducted at 24...

water and soil pollution by human pathogenic bacteria draw attention of many researchers. duration of bacterial survival for reach to the soil and water resources is very important. current study focused on the effects of caco3 and caso4 compounds on escherichia coli survival. using caco3, caso4 compounds and fine sand particles (