The invention relates to the use of a composite textile of natural and/or synthetic and/or artificial fibres and lignocellulose particles mixed with said fibres comprising more than 30 wt. % of said lignocellulose particles in order to trap the metals and/or metalloids and/or radionuclides and/or biocides present in water.

Provided are biomass-based materials and valuable uses of microalgal biomass including: (i) acetylation of microalgal biomass to produce a material useful in the production of thermoplastics; (ii) use of triglyceride containing microalgal biomass for production of thermoplastics; (iii) combination of microalgal biomass and at least one type of plant polymer to produce a material useful in the production of thermoplastics; (iv) anionization of microalgal biomass to form a water absorbant material; (v) cationization of microalgal biomass, and optional flocculation, to form a water absorbant material; (vi) crosslinking of anionized microalgal biomass; (vii) carbonization of microalgal biomass; and (viii) use of microalgal biomass in the making of paper.

Provided are biomass-based materials and valuable uses of microalgal biomass including: (i) acetylation of microalgal biomass to produce a material useful in the production of thermoplastics; (ii) use of triglyceride containing microalgal biomass for production of thermoplastics; (iii) combination of microalgal biomass and at least one type of plant polymer to produce a material useful in the production of thermoplastics; (iv) anionization of microalgal biomass to form a water absorbant material; (v) cationization of microalgal biomass, and optional flocculation, to form a water absorbant material; (vi) crosslinking of anionized microalgal biomass; (vii) carbonization of microalgal biomass; and (viii) use of microalgal biomass in the making of paper.

A biomass material for treating an effluent gas stream includes an algae biomass in an amount of from 40 weight % to 90 weight % based on a total weight of the biomass material and a zeolite in an amount of from 10 weight % to 60 weight % based on a total weight of the biomass material.

Provided is a technique capable of efficiently removing nitrogen contained in water to be treated and efficiently recovering microplastics from the water to be treated. An aspect of the present invention is a water treatment system 10 including an aquaculture tank 20 and a water treatment tank 30. Aquatic organisms are cultivated in the aquaculture tank 20. In the water treatment tank 30, algae having a microplastic adsorption and recovery ability grow in the water to be treated introduced from the aquaculture tank 20. The microplastics contained in the water to be treated are recovered, and the nitrogen compounds contained in the water to be treated are removed, by the algae.

The agent for selective metal recovery of the present invention includes a material derived from an alga belonging to the order Cyanidiales, which is dead cells or a cell surface layer of an alga belonging to the order Cyanidiales, or an artificial material produced by simulating the cell surface layer, or includes a porphyrin. The metal recovery method of the present invention includes an addition step of adding a material derived from an alga belonging to the order Cyanidiales, which is dead cells or a cell surface layer of an alga belonging to the order Cyanidiales, or an artificial material produced by simulating the cell surface layer, or adding a porphyrin, to a metal solution; and a recovery step of recovering a metal from the metal solution by the material derived from an alga belonging to the order Cyanidiales or the porphyrin.

The present disclosure provides an agent for selective metal recovery, a metal recovery method, and a metal elution method.