Agricultural drainage salt generated during irrigation of crops in San Joaquin Valley, California, exceeds 600,000 tons annually and cumulates in the field in a rapid rate. As a result, the waste is taking out more farmlands for salt storage and dispo...
Agricultural drainage salt generated during irrigation of crops in San Joaquin Valley, California, exceeds 600,000 tons annually and cumulates in the field in a rapid rate. As a result, the waste is taking out more farmlands for salt storage and disposal, imposing serious concerns to environment and local agricultural industry. In searching for a potential solution to reduce or eliminate the waste, this research explored feasibility of producing a value-added product, sodium sulfate, from the waste and utilizing the product in textile dyeing. The results indicated that sodium sulfate could be produced from the salt and could be purified by a recrystalization method in a temperature range within the highest and lowest daily temperatures in summer in the valley. The recovered sodium sulfate sample, with purities ranging from 67% to 99.91, were compared with commercially available sodium sulfate in the dyeing of levelling dyes with nylon/wool fabrics. In nylon/wool fabrics, C.I. Acid Yellow 23 had similar exhaustions among Na_2SO_4 Ⅰ, Na_2SO_4 Ⅱ, Na_2SO_4 Ⅲ and Na_2SO_4 Ⅴ which had similar ratios of sodium sulfate and sodium chloride in recovered salts. Na_2SO_4 Ⅳ had low exhaustion which had low ratios of sodium sulfate and sodium chloride. In nylon/wool fabrics, C.I. Acid Blue 158 had similar exhaustions among Na_2SO_4 Ⅰ, Na_2SO_4 Ⅱ, Na_2SO_4 Ⅲ and Na_2SO_4 Ⅳ and Na_2SO_4 Ⅴ despite of Na_2SO_4 Ⅳ had low ratios of sodium sulfate and sodium chloride. Generally, the dyeing of levelling dyes using recovered salts from farm drainage has similar or low exhaustion than the dyeing of levelling dyes using commercial sodium sulfate.