Ion exchange & reverse osmosis: A perfect combination

With 80 years of experience in water treatment and purification, the speciality chemicals company LANXESS with its Liquid Purification Technologies business unit (LPT), had a solid basis to appear at the recently-concluded IFAT, the world’s leading trade fair for water, sewage, waste, and raw materials management, held in Mumbai.

The Liquid Purification Technologies business unit now also sells modules for ultrafiltration (UF) through a marketing and distribution cooperation agreement with French UF membranes and system manufacturer Polymem. This adds ultrafiltration (UF) to the existing LANXESS range of water treatment technologies. It is a high-value, win-win partnership in this fast-growing membrane market for water treatment.

The reliable supply of drinking water to the world’s population is not the only challenge that constantly calls for new, innovative types of solutions. Water management in industry and agriculture also involves considerable challenges. “Intelligent technologies and tailored products that we offer, can help in the development of sustainable solutions. Efficient processing and recycling methods will be essential in order to meet the demand for water in the future,” adds Prakash Shanmugam, GM & Head of Business Unit – Liquid Purification Technologies (LPT) in India.

Numerous examples from the municipal and industrial sector show how ion exchange resins (IX) and reverse osmosis (RO) membranes complement one another to achieve optimal results in water treatment. As such, ion exchange resins can be installed in front of an RO unit, such as to remove organic impurities through adsorption, which would otherwise enable fouling on the membranes. Previous partial softening of the feed water with weak acidic ion exchange resin can also reduce both scaling on the membrane elements and the salt content of the feed with practically stoichiometric application of the regeneration agent. This enables more efficient operation of the RO plant. This procedure is recommended for highly carbonated, industrial process water.

A particular strength of ion exchange resins is their ability to selectively remove heavy metal cations or complex anions during the water purification process. LPT will present ion exchange resins, which include Lewatit TP 107 and Lewatit TP 207. The former, a strong basic, macroporous resin based on an interlaced polyacrylate, enables the efficient removal of various types of polyatomic oxyanions. Notable is the high capacity for chromate, as well as vanadate and molybdate, during the treatment of drinking water. Similar to Lewatit TP 106, it is certified according to NSF/ANSI standard 61.