Provided is a process and an apparatus for purifying boron nitride nanotube (BNNT) materials. The process involves the use of a halogen gas to remove halogen-reactive impurities from boron nitride nanotube (BNNT) materials in a single step with minimal interactions to produce structurally pristine BNNT. Gaseous byproducts are produced that 5 can be removed without the need for solution phase treatments. Yield efficiencies and purity of recovered BNNT are high compared to the other known methods of purification for BNNT material.

A particulate composition said composition comprises a metal carbonate and/or a metal bicarbonate and a compound of aluminium, characterised in that the weight ratio of metal carbonate plus metal bicarbonate compounds to said compound of aluminium is at least 3:1. The composition is useful for removing halogenated compounds from a hydrocarbon-containing process stream.

A waste gas purification system according to an embodiment includes an adsorption-catalysis-oxidation unit, an enhanced absorption unit, an air inducing unit, and a flue gas discharge and heat exchange unit that are sequentially connected. The waste gas enters a heat exchange device of the flue gas discharge and heat exchange unit through a first waste gas delivery pipeline to perform heat exchange, then is converged with waste gas in a second waste gas delivery pipeline and enters a third waste gas delivery pipeline. Waste gas in the third waste gas delivery pipeline is purified after sequentially passing through the adsorption-catalysis-oxidation unit and the enhanced absorption unit. Purified flue gas is introduced into the flue gas discharge and heat exchange unit by the air inducing unit, and the purified flue gas is discharged after performing heat exchange with the heat exchange device.

A gas scrubber includes a canister having a rotatable spiral separator which provides a non-linear path configured to be filled with modular adsorbent material portions between a gas inlet and a gas outlet.

Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO.sub.2 off-gas by heating the feed gas, optionally removing siloxanes and silanols from the heated feed gas, optionally removing part of the sulfur-containing compounds in the heated feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic conversion of any or all of the volatile organic compounds (VOCs) present in the gas, including sulfur-containing compounds, chlorine-containing compounds and any of the reactants injected, in at least one suitable reactor, and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H.sub.2, CO, ammonia, urea, methanol, ethanol and dimethyl ether (DME).

The present invention relates to a process for producing an aqueous solution containing chlorine dioxide from gaseous chlorine dioxide and from an aqueous phase. The invention additionally relates to an apparatus for producing an aqueous solution containing chlorine dioxide and/or for carrying out the process of the invention. Finally, the invention also relates to the use of an apparatus according to the invention for carrying out a process according to the invention. In the following, all statements made in respect of the process of the invention also apply correspondingly to the apparatus of the invention and the use according to the invention, and vice versa, unless indicated otherwise in the individual case.

An apparatus and method for purifying a raw hydrogen gas stream of chloramines and chlorine is provided. The explosive chloramines compounds can be effectively captured by the carbon adsorbent without accumulating on the carbon surface. Rather, the chloramines are converted via decomposition, into non-explosive products with catalytic effect of the carbon material. Chlorine reacts with impregnated reducing agent on the carbon surface to form the solid products, which can be adsorbed on the carbon surface. The purified hydrogen gas contains little to no trace of chloramines and chlorine impurities, thereby making the hydrogen gas suitable for liquid hydrogen production.

A gas chamber supply system includes a gas source configured to fluidly connect to a gas chamber and to supply a gas mixture to the gas chamber, the gas source including: a pre-prepared gas supply including a gas mixture, the gas mixture including a plurality of gas components and lacking a halogen; a recycled gas supply including the gas mixture; and a fluid flow switch connected to the pre-prepared gas supply and to the recycled gas supply. The gas chamber supply also includes a control system configured to: determine if the relative concentration between the gas components within the recycled gas supply is within an acceptable range; and provide a signal to the fluid flow switch to thereby select one of the pre-prepared gas supply and the recycled gas supply to as the gas source based on the determination.

A biogas cleaning method for purifying a biogas waste stream to form a combustible clean biofuel uses a biogas cleaning system that includes a gas control system, a deoxidizer catalyst bed, a hydrosulfurization catalyst bed, a hydrogen sulfide adsorption bed and a thermal sensor controller. The biogas cleaning method includes using a biogas source to introduce a biogas waste stream into the biogas cleaning system, blending hydrogen with the biogas waste stream, combusting the blended hydrogen and biogas stream to remove oxygen, hydrogenating the heated biogas waste stream to convert sulfur species to hydrogen sulfide and adsorbing the hydrogen sulfide from the biogas stream. In some embodiments, a biogas cleaning system also includes a sulfur polisher adsorption bed, a chlorine removal adsorption bed, a siloxane removal adsorption bed, a heat exchanger loop and a biogas precooler. Some embodiments of a biogas cleaning method can also include precooling the biogas waste stream, adsorbing siloxanes from the biogas waste stream and adsorbing hydrogen chloride from the biogas stream.

In one aspect the invention provides a fumigant gas capture apparatus. This apparatus includes at least one channel adapted for connection to a volume containing a fumigant gas, the channel defining an inlet which receives gas and an outlet which allows gas to exit the channel. The apparatus also includes at least one drive structure arranged to drive fumigant gas through the channel, at least one spray nozzle adapted to deliver a treatment liquid into the channel, and at least one packing element positioned within the channel to allow a spray nozzle or nozzle to spray treatment liquid on to the packing element.