An odor filter, preferably utilized on vents of human waste containers, provides a multi-stage construction having a variety of media calculated to remove specific gasses with acid and base impregnated filter media as well as potentially regular activated charcoal. The filter construction can be provided with a multi-diameter connection capability, at least one replacement indicator and/or a safety release to assist in at least one of under-pressure and/or overpressure situations.

A device for waste gas scrubbing in a urea plant may be configured such that a waste gas passes along a transportation direction in the duct. The duct may include a first region for removing urea dust particles from the waste gas and a second region for removing chemical compounds from the waste gas, which can be integrated by an acid-base reaction into an aqueous liquid phase. A cross-sectional area of the duct extending perpendicular to the transportation direction in the second region may be greater than a cross-sectional area extending perpendicular to the transportation direction in the first region. Further, the device may be configured such that the duct extends horizontally at least in sections and/or the transportation direction of the waste gas through the duct extends horizontally in an installed state.

The present invention covers a novel method for creating an adsorbent and the resulting novel adsorbent. The method may be used to remove pollutants/unwanted chemicals from water, air, other gases, biological fluids (such as blood, urine, lipids, protein fluids), and other fluids (such as fuel). The adsorbent may be used to remove heavy metals (for example, lead), organic pollutants, inorganic non-meal pollutants (for example, nitrates and bromates). Accordingly, the current invention has many applications including but not limited to water treatment, wastewater treatment, biomedical fluid treatments, gas cleanup, and fuel (oil, gas) cleanup.

An absorbent for selective removal of hydrogen sulfide over carbon dioxide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I)

##STR00001##

in which R.sub.1 and R.sub.2 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl, with the proviso that at least one R.sub.4 and/or R.sub.5 radical on the carbon atom bonded directly to the nitrogen atom is C.sub.1-4-alkyl or C.sub.1-4-hydroxyalkyl when R.sub.3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H.sub.2S selectivity to be set at pressures of the kind typical in natural gas processing.

A complex malodor removing equipment includes: a neutralizing module which dissolves a portion of malodor-causing substances, in malodorous gas introduced from malodor-producing equipment, in liquid water and removes same, which includes an acidity neutralizing module that introduces an alkaline substance from outside and removes an acidic malodor-causing substance from the malodor-causing substances, and an alkaline neutralizing module that introduces an acidic substance from outside and removes an alkaline malodor-causing substance from the malodor-causing substances, and which connects the acidity neutralizing module and the alkaline neutralizing module; and a balancing module which dissolves the remainder of the malodor-causing substances, in the malodorous gas introduced from the neutralizing module, in water and removes same, which includes an oxidation balancing module that introduces an oxidizing agent from outside and balances the malodor-causing substances, and a reduction balancing module that introduces a reducing agent from outside and balances the malodor-causing substances.

An air-cleaning filter includes a non-woven fabric for dust collection and a non-woven fabric for deodorization having activated carbon particles combined therewith. By adjusting the particle diameter and content of the activated carbon particles and laminating with a non-woven fabric coated with an absorber for other gases, a dust collecting function and a deodorizing function can be imparted at the same time while also creating a structure with a low differential pressure.

An absorbent for selective removal of hydrogen sulfide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I) ##STR00001##
in which R.sub.1 and R.sub.2 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl, with the proviso that at least one R.sub.4 and/or R.sub.5 radical on the carbon atom bonded directly to the nitrogen atom is C.sub.1-4-alkyl or C.sub.1-4-hydroxyalkyl when R.sub.3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H.sub.2S selectivity to be set at pressures of the kind typical in natural gas processing.

An air purification and recirculation system positioned within an animal rearing/sheltering facility. The system draws untreated air into an elongated air treatment apparatus having a dust scrubbing section, an ammonia scrubbing section, and acid scrubbing section, configured so that the treatment sections are positioned in series. At the end of the air treatment process, the treated air is exhausted back into the animal rearing facility so that the air is circulated within the facility. Acid and water used during the air treatment process are continuously recycled and directed back through the scrubbers in the air treatment apparatus.

Disclosed is an apparatus for separating amine gas from mixed gas, the apparatus including: a washer column through which mixed the gas passes; and a main adsorber column through which the mixed gas passing through the washer column passes. According to the present invention, the apparatus can remove amine gas more effectively and increase the lifetime of an adsorbent by allowing the mixed gas including the amine gas to pass through the washer column and the adsorber column.

Removing waste gas, more particularly carbon dioxide, from a gaseous medium and producing gaseous oxygen, a recovered waste constituent, more particularly solid carbon, heat and electrical power, by means of chemical reaction of waste gas with a metal oxide, more particularly dodecatungstophosphoric acid, immobilized in a porous matrix, more particularly tetraethylorthosilicate sol gel, enclosed in a gas permeable membrane. Regeneration of the metal oxide, more particularly by heating, and reconstitution of the porous matrix containing same by periodic introduction of base materials, and in some cases with externally supplied energy.