The present invention provides a multi-stage filter system suitable for the production of drinking water from a wide variety of contaminated water sources. The modular nature of the multi-stage filter system allows for the customization of filter combinations according to the remediation requirements. The multi-stage filter system comprises a coarse filter (S1); an ultrafiltration filter (S2); a graphene-based filter (S3); and a residual nanoparticle filter (S4). The graphene-based filter cartridge comprises few-layer graphene powder; a combination of few-layer graphene powder and pellets comprising a mixture of polyethersulfone, graphene oxide (GO), and dimethylformamide; a composite comprising chitosan, GO, sodium sulfate and ferric chloride; or a combination of few-layer graphene powder, granular activated carbon and a composite comprising chitosan, GO, sodium sulfate and ferric chloride.

A method for producing a modified sawdust sorbent. The method involves sulfonating sawdust with sulfuric acid and oxidizing the sulfonated sawdust with hydrogen peroxide. The method yields a modified sawdust sorbent containing sulfonated and oxidized cellulose. The modified sawdust sorbent has a higher surface area, higher organic dye adsorption capacity, and more rapid organic dye adsorption rate than unmodified sawdust. Also disclosed is a method of using the modified sawdust sorbent for organic dye removal from water.

A composite nanomaterial of ZnO impregnated by, e.g., a green copper phthalocyanine compound (CuPc) can be an efficient solar light photocatalyst for water remediation. The composite may include hollow shell microspheres and hollow nanospheres of CuPc-ZnO. CuPc may function as a templating and/or structure modifying agent, e.g., for forming hollow microspheres and/or nanospheres of ZnO particles. The composite can photocatalyze the degradation of organic pollutants such as crystal violet (CV) and 2,4-dichlorophenoxyacetic acid as well as microbes in water under solar light irradiation. The ZnO—CuPc composite can be stable and recyclable under solar irradiation.

Copper-boron-ferrite (Cu—B—Fe) composites may be prepared and immobilized on graphite electrodes in a silica-based sol-gel, e.g., from rice husks. Different bimetallic loading ratios can produce fast in-situ electrogeneration of reactive oxygen species, H.sub.2O.sub.2 and .OH, e.g., via droplet flow-assisted heterogeneous electro-Fenton reactor system. Loading ratios of, e.g., 10 to 30 wt. % Fe.sup.3+ and 5 to 15% wt. Cu.sup.2+, can improve the catalytic activities towards pharmaceutical beta blockers (atenolol and propranolol) degradation in water. Degradation efficiencies of at least 99.9% for both propranolol and atenolol in hospital wastewater were demonstrated. Radicals of .OH in degradation indicate a surface mechanism at inventive cathodes with correlated contributions of iron and copper. Copper and iron can be embedded in porous graphite electrode surface and catalyze the conversion of H.sub.2O.sub.2 to .OH to enhance the degradation. Inventive cathodes can be stable catalytically after 20 or more cycles under neutral and acidic conditions.

The invention relates to the field of industrial wastewater treatment, and particularly discloses a nanofiltration membrane for treating printing and dyeing wastewater and its preparation method. The preparation method comprises the following steps: S1, pouring an aqueous solution containing m-phenylenediamine, camphorsulfonic acid and triethylamine onto the surface of a polysulfone ultrafiltration membrane, setting still for 10 s to 30 s, and then removing the excess aqueous solution from the surface; S2, pouring an organic solution containing trimesoyl chloride and an interface auxiliary polymerization agent onto the surface of the membrane obtained in step S1, reacting for 5 s to 20 s, and then removing the excess solution from the surface; and S3, setting the membrane obtained in step S2 still and then carrying out heat treatment and water rinsing on the membrane in sequence, thus obtaining the nanofiltration membrane.

An asymmetric system containing a first conductive polymer modified with a redox active moiety and a second conductive polymer modified with a surfactant is used for the separation of organic compounds from aqueous solutions. The asymmetric system has complementary hydrophobicity tunability in response to electrochemical modulations. For example, both materials are hydrophobic in their respective neutral states, therefore exhibiting affinity toward organic compounds. Application of a mild potential drives the desorption of the organic compounds and regeneration of the materials. The asymmetric system can be used in a cyclic fashion, through repeated electrical discharge or shorting of the two electrodes to program the capture of organics from a feed solution, and application of a potential to stimulate the release of the adsorbed organics.

A permeable reactive barrier having two or more layers of a geotextile fabric inoculated with a bioremediation microbe is provided. The permeable reactive barrier further includes two or more layers of coarse-grained geological material separating the two or more layers of geotextile fabric such that any pair of adjacent layers of geotextile fabric is separated by a layer of coarse-grained geological material. The permeable reactive barrier includes a perforated metal casing surrounding and containing the layers of coarse-grained geological materials and geotextile fabric.

A cerium oxide nanoparticle is produced by mixing a solution of an aromatic heterocyclic compound having no substituent or at least one substituent selected from the group consisting of a methyl group, an ethyl group, an amino group, an aminomethyl group, a monomethylamino group, a dimethylamino group, and a cyano group and containing 2 to 8 carbon atoms and 1 to 4 nitrogen atoms in a ring structure of the aromatic heterocyclic compound, with a solution containing a cerium (III) ion or with a cerium (III) salt, followed by addition of an oxidant.

A composite nanomaterial of ZnO impregnated by, e.g., a green copper phthalocyanine compound (CuPc) can be an efficient solar light photocatalyst for water remediation. The composite may include hollow shell microspheres and hollow nanospheres of CuPc-ZnO. CuPc may function as a templating and/or structure modifying agent, e.g., for forming hollow microspheres and/or nanospheres of ZnO particles. The composite can photocatalyze the degradation of organic pollutants such as crystal violet (CV) and 2,4-dichlorophenoxyacetic acid as well as microbes in water under solar light irradiation. The ZnO—CuPc composite can be stable and recyclable under solar irradiation.

Methods for removing contaminants from aqueous media using polyelectrolyte complexes having a heterogeneous charge distribution are provided. The polyelectrolyte complexes are formed from an amphiphilic anionic random copolymer and a cationic random copolymer are provided. The polyelectrolyte complexes absorb cationic, anionic, or hydrophobic organic molecules and can be easily removed from water.