Superhydrophobic coatings and compositions and methods for preparing superhydrophobic coatings and compositions are described herein whereby the coatings and compositions are prepared under mild conditions, yet the methods are amenable to chemical functionalization of the coatings and components therein. The methods are useful for tuning and optimizing the physical properties of the coatings. In an embodiment, the coatings comprise nanostructured fluorinated silica colloids.

An efficient and energy-saving system for recycling waste heat of production includes a wet-steam waste-heat recycling module configured to recycle heat of a hot and wet steam produced during a drying process of a material, where the wet-steam waste-heat recycling module includes a conveyor belt configured to carry the material, a plurality of dryers, a compressor, and/or a heat exchanger. The conveyor belt passes through the plurality of dryers in sequence, each of the dryers is connected to the compressor and/or the heat exchanger through a pipeline, and the hot and wet steam produced by the compressor and/or the heat exchanger is reused for drying the material. A process for recycling waste heat of production is further provided. A method for large-scale production of silica gel allows the formation of an eco-friendly cycle during silica gel production, does not involve the emission of (waste gas, waste water and waste residues.

An efficient and energy-saving system for recycling waste heat of production includes a wet-steam waste-heat recycling module configured to recycle heat of a hot and wet steam produced during a drying process of a material, where the wet-steam waste-heat recycling module includes a conveyor belt configured to carry the material, a plurality of dryers, a compressor, and/or a heat exchanger. The conveyor belt passes through the plurality of dryers in sequence, each of the dryers is connected to the compressor and/or the heat exchanger through a pipeline, and the hot and wet steam produced by the compressor and/or the heat exchanger is reused for drying the material. A process for recycling waste heat of production is further provided. A method for large-scale production of silica gel allows the formation of an eco-friendly cycle during silica gel production, does not involve the emission of (waste gas, waste water and waste residues.

An efficient and energy-saving system for recycling waste heat of production includes a wet-steam waste-heat recycling module configured to recycle heat of a hot and wet steam produced during a drying process of a material, where the wet-steam waste-heat recycling module includes a conveyor belt configured to carry the material, a plurality of dryers, a compressor, and/or a heat exchanger. The conveyor belt passes through the plurality of dryers in sequence, each of the dryers is connected to the compressor and/or the heat exchanger through a pipeline, and the hot and wet steam produced by the compressor and/or the heat exchanger is reused for drying the material. A process for recycling waste heat of production is further provided. A method for large-scale production of silica gel allows the formation of an eco-friendly cycle during silica gel production, does not involve the emission of (waste gas, waste water and waste residues.

An efficient and energy-saving system for recycling waste heat of production includes a wet-steam waste-heat recycling module configured to recycle heat of a hot and wet steam produced during a drying process of a material, where the wet-steam waste-heat recycling module includes a conveyor belt configured to carry the material, a plurality of dryers, a compressor, and/or a heat exchanger. The conveyor belt passes through the plurality of dryers in sequence, each of the dryers is connected to the compressor and/or the heat exchanger through a pipeline, and the hot and wet steam produced by the compressor and/or the heat exchanger is reused for drying the material. A process for recycling waste heat of production is further provided. A method for large-scale production of silica gel allows the formation of an eco-friendly cycle during silica gel production, does not involve the emission of (waste gas, waste water and waste residues.

Provided is a hollow particle, including silica, having a D.sub.SL of primary particles that satisfies the following expression (1), and having a breaking strength of 10 MPa or more: 1D.sub.SL1.5 . . . (1) where D.sub.SL=D.sub.75L/D.sub.25L, and D.sub.25L and D.sub.75L represent a 25th value and a 75th value, respectively, when long diameters of 100 randomly selected primary particles are measured in observation with a scanning electron microscope and sorted in order of increasing size.

Provided is a hollow particle, including silica, having a D.sub.SL of primary particles that satisfies the following expression (1), and having a breaking strength of 10 MPa or more: 1D.sub.SL1.5 . . . (1) where D.sub.SL=D.sub.75L/D.sub.25L, and D.sub.25L and D.sub.75L represent a 25th value and a 75th value, respectively, when long diameters of 100 randomly selected primary particles are measured in observation with a scanning electron microscope and sorted in order of increasing size.