Search results
Results from the WOW.Com Content Network
Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH).Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid rain has a pH level lower than this and ranges from 4–5 on average.
Many limestone statues and building surfaces have suffered severe damage due to acid rain. [111] [112] Likewise limestone gravel has been used to protect lakes vulnerable to acid rain, acting as a pH buffering agent. [113] Acid-based cleaning chemicals can also etch limestone, which should only be cleaned with a neutral or mild alkali-based ...
Diagram depicting the sources and cycles of acid rain precipitation. Freshwater acidification occurs when acidic inputs enter a body of fresh water through the weathering of rocks, invasion of acidifying gas (e.g. carbon dioxide), or by the reduction of acid anions, like sulfate and nitrate within a lake, pond, or reservoir. [1]
Often, limestone rocks or appropriate calcareous strata that could contribute to neutralize acid effluents are lacking, or insufficiently accessible (too short contact time with acidic waters flowing too fast, too low specific surface area, insufficient contact…), at sites affected by acidic rock drainage. In such cases, crushed limestone can ...
Pure lime is soluble in water containing carbonic acid, a natural, weak acid which is a solution of carbon dioxide in water and acid rain so it will slowly wash away, but this characteristic also produces autogenous or self-healing process where the dissolved lime can flow into cracks in the material and be redeposited, automatically repairing ...
This reaction is at the core of the alkali–silica reaction (ASR): 2 NaOH + SiO 2 → Na 2 SiO 3 · H 2 O. Following this reaction, a hygroscopic and expansive viscous silicagel phase forms inside the affected aggregates which swell and crack from inside. In its turn, the volumetric expansion of the swollen aggregates damages the concrete ...
In acid soils, these materials react as a base and neutralize soil acidity. This often improves plant growth and increases the activity of soil bacteria, [1] but oversupply may result in harm to plant life. Modern liming was preceded by marling, a process of spreading raw chalk and lime debris across soil, in an attempt to modify pH or ...
Agricultural lime, also called aglime, agricultural limestone, garden lime or liming, is a soil additive made from pulverized limestone or chalk. The primary active component is calcium carbonate . Additional chemicals vary depending on the mineral source and may include calcium oxide .