草酸酸洗对麦草氧脱木素浆中铁离子去除及H2O2漂白的影响

Effect of Oxalic Acid Washing on the Content of Fe3+ in Oxygen Delignified Wheat Straw Pulp and Its Hydrogen Peroxide Bleaching

中文关键词:  草酸酸洗  麦草  氧脱木素浆料  铁离子  过氧化氢漂白

Key Words:oxalic acid washing  wheat straw  oxygen delignified pulp  ferric ion  hydrogen peroxide bleaching

中文摘要:

      以麦草氧脱木素（O）浆为研究对象，考察了草酸酸洗（AC）对该浆料中铁离子去除率及后续过氧化氢（P）漂白的促进作用。结果表明，当pH值约为3、浆浓4%时，较优的草酸酸洗温度和处理时间分别为60℃和60 min，此时Fe3+的去除率约为40%。这主要是由于草酸除可提供酸性环境外，还可络合Fe3+，降低Fe3+在浆料纤维上的吸附量，改变Fe(OH)3的溶解平衡，在相同氢离子浓度时达到提高Fe3+去除率的目的。浆料卡伯值和黏度相同时，与经OQP和OAS（硫酸酸洗）QP漂后的浆料白度（分别为56.4%和64.5%）相比，经OACQP漂白后浆料白度可达73%，分别提高了30%和13%。

Abstract:

      By using oxygen delignified wheat straw pulp as material， the role of oxalic acid washing (AC) in improving Fe3+ removal and subsequent hydrogen peroxide bleaching efficiency was studied．It was found that Fe3+ removal was about 40% when pH value of washing liquor and pulp consistency were fixed as 3 and 4%, optimal treatment time and temperature of AC were 60 min and 60℃ respectively． In addition to providing acidic environment， oxalic acid could chelate Fe3+， decrease its absorption on pulp and thus change dissolving balance of Fe(OH)3． Based on these functions， the target for improving Fe3+ removal could be achieved by AC． With the same pulp kappa number and viscosity， the brightness of the pulp bleached with the OACQP sequence was 73%， which was higher than those bleached with OQP (56.4%) and OAS（sulfuric acid washing）QP (64.5%) by about 30% and 13%．