The present invention relates to an immunoglobulin-binding protein, wherein at least one asparagine residue has been mutated to an amino acid other than glutamine or aspartic acid, which mutation confers an increased chemical stability at pH-values of up to about 13-14 compared to the parental molecule. The protein can for example be derived from a protein capable of binding to other regions of the immunoglobulin molecule than the complementarity determining regions (CDR), such as protein A, and preferably the B-domain of Staphylococcal protein A. The invention also relates to a matrix for affinity separation, which comprises an immunoglobulin-binding protein as ligand coupled to a solid support, in which protein ligand at least one asparagine residue has been mutated to an amino acid other than glutamine.

A silicon-based solid amine sorbent for CO.sub.2 and the making method thereof including: providing a silicon source liquid which is a silicate solution or a liquid organosilicate, wherein the silicate solution comprises water and a first silicate dissolved in the water; mixing the silicon source liquid with a precipitant to perform a precipitation reaction to obtain a product liquid containing a precipitate, wherein the precipitate is a second silicate or silicic acid; filtering out the precipitate and washing the precipitate with water; mixing the precipitate filtrated out but not dried yet with an organic alcohol and then performing an azeotropic distillation to obtain a dehydrated precipitate; calcining the dehydrated precipitate to obtain a silicon-based support, wherein the silicon-based support is a powder of the second silicate powder or a silica powder; and impregnating the silicon-based support with an organic amine solution and then drying to obtain the silicon-based amine-containing solid sorbent for CO.sub.2.

The present invention relates to chromatography ligands having improved caustic stability, e.g., ligands based on immunoglobulin-binding proteins such as, Staphylococcal protein A, as well as methods of making and using such ligands.

Structured sorbents including a metal organic framework, hydrophobic binder, and hydrophobic carrier, wherein the hydrophobic carrier includes fluorinated silica. Methods of making structured sorbents and using structured sorbents in direct air capture of CO.sub.2.