Ứng dụng vật liệu xanh nanocompozit để hấp phụ ion Cadimi trong nước thải

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Tác giả: Minh Nguyệt Hà, Thu Hà Hoàng, Đình Minh Trần

Ngôn ngữ: Vie

Ký hiệu phân loại:

Thông tin xuất bản: Các khoa học Trái đất và Môi trường (ĐHQG Hà Nội) 2021

Mô tả vật lý: 61-68

Bộ sưu tập: Metadata

ID: 404386

Thêm vào giỏ Liên kết toàn văn

Tốc độ phát triển công nghiệp và hiện đại hóa xã hội quá nhanh trong những thập kỉ gần đây đã dẫn đến những hệ lụy nghiêm trọng đối với môi trường. Nhiều khảo sát cho thấy môi trường nước đang bị ô nhiễm bởi các loại nước thải công nghiệp và nông nghiệp cũng như dư lượng y, dược phẩm. Nguyên nhân được cho là do các nguồn phát thải này thường không được xử lý hiệu quả trước khi được đưa ra ngoài môi trường, khiến một lượng đáng kể các chất ô nhiễm bị tích tụ lại trong nước, đe dọa nghiêm trọng đến sức khỏe của con người. Trong số các chất ô nhiễm đã được phát hiện, Cadimi và các hợp chất của Cadimi được xem là một trong những tác nhân nguy hiểm nhất. Cadimi và các hợp chất của Cadimi có thể xuất phát từ các nguồn thải khác nhau như tinh luyện kim loại, hợp kim và mạ kim loại, và pin Cd-Ni, gây ra nguy hiểm cho sức khỏe cộng đồng và môi trường. Dự án này nghiên cứu phát triển một loại vật liệu "xanh" có khả năng xử lý Cd (II) với hiệu suất cao. "Vật liệu xanh" là khái niệm chung được sử dụng cho các vật liệu chỉ chứa các thành phần thân thiện với môi trường, nghĩa là không độc hại đối với người và sinh vật, có khả năng tự phân hủy hoặc phân hủy sinh học. Vật liệu nanocompozit mới được tổng hợp từ quy trình hai bước, bao gồm chức năng hóa bề mặt các hạt oxit silic (SiO2) bằng polianilin (PANI) rồi sau đó phân tán SiO2/PANI trong etanol nhờ sóng siêu âm. Silica, polianilin và etanol đều là những chất không gây ảnh hưởng tiêu cực đến môi trường và được sử dụng rộng rãi trong nhiều lĩnh vực. Vật liệu được chế tạo thành công và xác định các đặc trưng lý hóa bằng các phương pháp, kỹ thuật hiện đại như phổ hồng ngoại FTIR, kính hiển vi điện tử quét SEM, kính hiển vi điện tử truyền qua TEM và phân tích diện tích bề mặt BET. Các công thức tính dung lượng hấp phụ, hấp phụ đẳng nhiệt Langmuir, và phương trình động học của phản ứng bậc 1 và bậc 2 đã chứng minh CSP có khả năng xử lý Cd (II) nhanh và hiệu quả, với dung lượng hấp phụ cực đại 301,23 mg/g, cao hơn so với các vật liệu đã được nghiên cứu trước đây. Kết quả khảo sát các điều kiện tối ưu cho thấy Cd (II) bị hấp phụ tối ưu ở các điều kiện pH 6, thời gian phản ứng 150 phút, với nồng độ Cd (II) ban đầu là 300 mg/L và khối lượng vật liệu CSP là 0,6 g. Các kết quả hấp phụ cho thấy rằng pH là yếu tố quan trọng nhất trong quá trình hấp phụ và xử lý Cd (II) do sự hình thành các phức chất trong dung dịch giữa ion Cd (II) và các nhóm chức bề mặt của CSP như nhóm hydroxyl (OH- ), silanol (Si-OH), amine (-NH2), quinoid imine [C=N-] và benzenoid amine [-NH-]. Ưu điểm nổi bật của dự án là đã chế tạo thành công vật liệu "xanh" nanocompozit có cấu trúc hai lớp nhân-lõi SiO2 và vỏ PANI nhờ phương pháp sol-gel và công nghệ phân tán vật liệu bằng sóng siêu âm, thân thiện với môi trường và con người., Tóm tắt tiếng anh, : In the condition of industrialization, the water environment has been contaminated by industrial and agricultural waste as well as pharmaceutical residuals. These sources of waste water are usually treated efficiently prior to releasing into environment. This leads to a significant quantity of pollutants accumulated in water, threating seriously to human health. Among various detected pollutants, Cadmium and its compounds are considered as one of the most dangerous reagents. They can be released to the environment from different sources of waste, such as metal, alloy and metal plating, and Cd-Ni batteries, which clearly showed a danger to the human health. This work aims to develop a novel "green" material applied for highly efficient treatment of Cd (II). The concept "Green material" indicates the material which is composed of environmental-friendly compounds (non-toxic to human and organisms, degradable or biodegradable). The novel material C2H5OHSiO2/PANI (CSP) was synthesized using two-step procedure including functionalization of silicon oxide nanoparticles (SiO2) by polyaniline polymer (PANI) and dispersion of SiO2/PANI in ethanol under ultrasound sonication. All components of CSP including Silica, ethanol, PANI do not have negative effect on environment, thus they are applied in plenty of fields. CSP were successfully synthesized and characterized by several methods and techniques such as FTIR, SEM, TEM and BET analysis. Based on the practical data, the Cd (II) adsorption was followed by Langmuir adsorption isotherms, and the pseudo-second order adsorption kinetic. CSP has obtained the Cd (II) maximum adsorption capacity of 301.23 mgg-1 , which is higher than the previous reported adsorbents. Cd (II) adsorption by CSP is desired at pH 6, reaction time of 150 min, initial concentration of Cd (II) as 300 mgL-1 , CSP weight as 0.6 g. Adsorption data show that pH is one of the most important factor in Cd (II) adsorption due to the formation of surface complexes between Cd (II) and the functional groups of CSP such as hydroxyl group (OH- ), silanol (Si-OH), amine (- NH2), quinoid imine [C=N-] and benzenoid amine [-NH-].

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