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Waste valorization: Recovery of lactose from partially deproteinated whey by using acetone as anti-solvent

丙酮反溶剂法从部分脱蛋白乳清中回收乳糖

Sanjay R. Patel and Z. V. Panchakshari Murthy^*

Chemical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Surat 395007, Gujarat, India

^* Corresponding author (通讯作者): zvpm2000@yahoo.com, zvpm@ched.svnit.ac.in

Received: 15 December 2009
Revised: 31 May 2010
Accepted: 8 June 2010

Abstract

The treatment of dairy wastewater which conforms to environmental regulations is a crucial problem due to its high biological oxygen demand (BOD). The main cause of the BOD in dairy wastewater is due to residual whey which consists mainly of lactose. Recovery of lactose from the whey would solve the problems of whey utilization as well as pollution reduction as lactose recovery itself can reduce the BOD of whey by > 80%. In the present study, the recovery of lactose from partially deproteinated whey by the use of an anti-solvent (acetone) was investigated. Process parameters, such as acetone concentration (65–85% v/v), time (1–3 h), stirring speed (500–1000 rpm), seeding (1–3% w/w) and pH, were varied. The results suggest that > 90% of lactose was recovered from whey after 1 h of stirring at an acetone concentration of 85% v/v. The crystal size distribution of the lactose recovered from whey was estimated by image analysis and found to be affected by crystallization time as well as seeding.

摘要

乳制品生产废水的生物需氧量 (BOD) 较高、废水必须经过处理以达到环保排放标准。奶废水中生物需氧量 (BOD) 较高的主要原因是由于残留的乳清含有大量的乳糖。从乳清中回收乳糖既能够解决乳清再利用的问题、乳糖回收能够将乳清中的生物需氧量减少 80% 以上、同时也减少了乳糖造成的环境污染问题。本文通过利用丙酮作为反溶剂、从部分脱蛋白乳清中回收乳糖。实验参数为丙酮浓度 (65–85% v/v)、时间 (1–3 h)、搅拌速度 (500–1000 rpm)、添加的晶种量 (1–3% w/w) 和 pH。实验结果表明、在丙酮浓度为 85% (v/v) 的情况下搅拌 1 h 后、乳糖回收率可以达到 90% 以上。从乳清中回收的乳糖的晶体粒径分布 (CSD) 通过影像分析仪发现、乳糖的晶体粒径分布 (CSD) 受结晶时间和添加的晶种量影响。